Is astronomy becoming a winter sport

Remember those clear summer nights when you’d haul out the telescope in July wearing just shorts and a T-shirt, to gaze up at the Milky Way arching overhead? Lately, however, those idyllic summer stargazing nights have become as rare as a snowflake in June. Across much of the country, frustrated sky-watchers are asking a tongue-in-cheek question: Is astronomy turning into a winter sport? In other words, are the cold months now the only reliable time to enjoy our telescopes under clear skies? To answer that, we need to take a tour through the shifting weather patterns that are throwing a wrench in our celestial plans.

Stormier summers, smokier skies, but does that mean Is Astronomy becoming a winter sport or not?

Wildfire smoke has become a new kind of cloud for astronomers, one that turns a once-clear summer sky into a hazy soup. In recent years, massive forest fires have blanketed vast regions with smoke, obscuring the stars for weeks on end.

In many parts of the United States, summer has traditionally been prime stargazing season. Schools are out, nights are comfortably warm, and the Milky Way’s core dazzles overhead. But recently, summer skies have been under siege from extreme weather. Heat waves roll in and park themselves for days or weeks, turning the atmosphere into a shimmering skillet. That heat brings high humidity, meaning the air is laden with moisture that softens the sky’s transparency. Even on a nominally “clear” night, a sultry summer atmosphere can make the stars fade behind a gauzy veil of water vapor. It’s as if the sky itself is sweating.

Then there’s the relentless rain and storms (don't get me started abouto rain here in Missouri). In many regions, climate shifts have made summer weather patterns less predictable and often more stormy. One week you’re roasting under a heat dome, the next you’re watching thunderstorms and torrential downpours night after night. Those storms don’t just disappear at sunset, either, they leave behind layers of clouds that can linger for days. An astronomy enthusiast in Missouri might quip that lately there have been more rain dates than star parties in June and July. Summer’s once-reliable clear nights have become a gamble, with clouds often winning the hand.

Perhaps the biggest new villain of summer stargazing is wildfire smoke. As summers have grown hotter and drier in many areas, wildfires have exploded in frequency and size. The American West and even parts of Canada have seen record-breaking fire seasons in the past few years, and all that smoke doesn’t stay put over the forests, it spreads out for hundreds or thousands of miles. In late 2023, for example, giant fires in Canada sent plumes of smoke southward, and observers across the Midwest and Northeast woke up under brownish, hazy skies that persisted for weeks. Even at night, the smoke turned normally dark rural skies an eerie shade of gray, blotting out all but the brightest planets and stars. At one point that summer, satellites showed that over 90% of North America’s sky was affected by wildfire smoke. That statistic is almost unbelievable, yet many of us experienced it firsthand, stepping outside to see a murky glow where the Milky Way should be.

The trouble with smoke is that it can linger even when the weather is otherwise good. You might get excited because the forecast calls for no clouds, only to find the stars are still hiding behind a diffuse smoky film. Veteran astronomers now monitor air quality indexes and wildfire maps as closely as they do cloud forecasts. One meteorologist who provides specialized forecasts for astronomers noted that in today’s climate, there is enough smoke in the air from April to October to degrade the sky on well over half of the otherwise clear nights. In other words, even when we docatch a break from clouds in summer, there’s a good chance smoke will crash the party.

All these factors have led some sky-watchers to essentially write off the summer. “Astronomy in Florida is a winter sport,” one hobbyist in the Sunshine State declared, noting that between the mosquitoes, humidity, and near-nightly thunderstorms, he packs away his telescope after spring and doesn’t expect to use it again until November. It’s a sentiment being echoed in many places. Across the central and eastern U.S., folks who once relished the long, lazy summer evenings under the stars are now left twiddling their thumbs (or compulsively checking weather apps) for weeks on end, waiting for a single clear night that never comes. It’s the great irony of our time: the warmest months have become the hardest to enjoy for astronomy. Like a cruel joke, the universe is still putting on its grand summer showcase, the dense star clouds of Sagittarius, the Perseid meteor shower in August, but down here we often can’t see it through the clouds, haze, and smoke.

The lure of the winter sky

A cold, crisp winter night often rewards stargazers with a brilliant, crystal-clear sky. In the frigid air, stars shine steadier and brighter, here the constellation Orion rises above a quiet, snow-dusted landscape.

Given the challenges of spring and summer, more astronomers are turning their gaze (and hopes) toward winter, despite its hardships. Winter observing has never been for the faint of heart, it means bundling up in multiple layers, fumbling with frozen fingers to adjust telescope knobs, and perhaps clearing snow off your eyepiece case. But the payoff can be extraordinary. Cold air is dry air, and dry air makes for superbly transparent skies. On a calm winter night after a cold front passes, the atmosphere contains very little moisture and hardly any of the pollen, dust, or smoke particles that plague the summertime. The stars don’t just twinkle, they pierce right through the darkness, sharp and untinted, like diamonds on black velvet.

Many veteran stargazers will tell you that the best nights of the year are often in late fall or winter. The long nights and crisp air combine to produce stunning views of the cosmos. In fact, winter’s stability can be a relief after summer’s turbulence. During the warm months, even at night the ground is still releasing heat from the day, causing air currents that blur telescopic images (imagine looking over a hot road and seeing the wavy mirage, that’s bad news for astronomy). In winter, especially on a still night, the atmosphere can be more stable, meaning the stars hardly flicker and you can push your telescope to higher magnifications for detailed views of planets and the Moon. There’s a reason some of the most iconic deep-sky images (like those crisp photos of the Orion Nebula or the Andromeda Galaxy) are often captured in the cold months, the combination of clarity and steadiness is a gift to astrophotographers.

Of course, winter has its own brand of unpredictability. Blizzards and heavy snow can wipe out the sky for days, and some regions (like the Pacific Northwest) suffer a solid overcast from November through January due to persistent storm tracks. But crucially, when a winter high-pressure system moves in, it tends to park overhead and deliver several nights of clear, calm weather. Think of those stretches of days when it’s cold, dry, and sunny, those correspond to nights that are cold, dry, and starry. In contrast to summer’s quick, pop-up thunderstorms that break up one night and return the next, winter’s weather patterns are a bit slower and steadier. A high-pressure ridge over the Midwest in January might bring a whole week of cloud-free skies (albeit subzero ones!). For an avid astronomer, that means an uninterrupted week to catch up on observing, something almost unheard of in July.

Another factor tipping the balance towards winter is simply the length of night. In the heart of summer, especially at higher latitudes, darkness may not even arrive until 10 PM and might be gone by 4 AM. That’s a narrow window for those of us chasing faint galaxies; you barely finish aligning your telescope and it’s already getting light. By contrast, in December the sky is fully dark by dinnertime and stays that way for a good 12-14 hours. You can start a photography session at 6 PM, take a snack break at midnight (when it’s still pitch black outside), and continue collecting photons until the birds start chirping. For anyone who values quantity of observing time, winter wins hands down. The only problem, of course, is surviving the chill for that long. It’s a running joke among astronomers that the cost of an 8-hour winter imaging session is about 3 packs of hand warmers and maybe a little bit of frostbite risk. But ask any deep-sky photographer and they’ll tell you it’s worth it when you finally check the images and see those pin-point stars and vibrant nebulas you captured while the world was frozen and asleep.

It’s worth noting that in some locales, astronomy has always been a winter-centric hobby. Take the desert Southwest: places like Arizona have a rainy monsoon season in the summer that brings clouds and thunderstorms almost every afternoon and evening. Come winter, though, the desert skies are typically bone-dry and clear night after night. Observatories in Arizona schedule their maintenance for July because they know there won’t be many usable nights, whereas December is usually a goldmine of clear observing. The same goes for the Southeast, for much of Florida and the Gulf Coast, summer is hurricane and storm season (not to mention steamy and bug-ridden), whereas the cooler months tend to be drier and more stable. An astronomer in New Orleans once told me that from May through September, he mostly polishes his lenses and reads astronomy books, because stepping outside means being eaten alive by mosquitoes under a cloudy, humid sky. But come winter, the mosquitoes vanish and the dry northerly air flows in, bringing nights where Orion and Sirius sparkle overhead in rare clarity.

Even in areas that historically had great summer weather, say, the high elevations of California or the Rocky Mountains, winter has become more appealing because summer now carries the risk of wildfire smoke as well. The Pacific Northwest, as another example, flips the script (with summers traditionally clear and winters socked in by rain). Yet in recent years, even those beautiful Northwest summer nights have been tainted by smoke from regional fires in August and September. So an astronomy buff in Oregon might actually prefer the chilly but smoke-free periods of early spring or late fall over the height of summer.

All told, there’s a growing consensus among sky enthusiasts that if you truly want reliable stargazing, you better be ready to embrace the cold. Yes, you’ll need to invest in some thermal underwear, insulated boots, maybe even heated telescope accessories to prevent your gear from icing up. But the reward is that feeling of stepping outside on a still, bitterly cold night and seeing everything above, thousands of stars unhindered by haze, the winter Milky Way like a faint silver river, and maybe a few of those subtle winter phenomena like the zodiacal light or an aurora dancing on the horizon. Those are the nights that remind you why you fell in love with the sky in the first place. And increasingly, they seem to be found in January rather than July.

Twenty years of changing sky patterns

All this talk of crazy weather and climate shifts begs the question: is it really worse now than it was 20 years ago, or are we just feeling a short-term unlucky streak? To answer that, we can look at both hard data and the “soft” data of human experience. Both paint a picture of a sky that is indeed changing, and not for the better (unless you’re a fan of clouds).

Let’s start with the meteorological data. Over the past two decades, the United States has seen a notable increase in extreme weather events, many of which directly impact sky conditions. For one, the country as a whole has gotten warmer, especially the nights. Warmer air holds more moisture, and with more moisture we get more clouds and higher humidity levels. Climatologists have measured a rise in average dew points (a measure of humidity) in many regions since the early 2000s. If you’ve ever stepped out on a July night and felt like you were swimming through the air, that’s a higher dew point you’re feeling, and it’s bad news for clear skies. A more humid climate means even if clouds dissipate, a thin haze often remains, washing out faint stars.

Precipitation has also increased in many parts of the country. The late 2010s, for example, brought some of the wettest years on record for the U.S. The 12-month period from mid-2018 to mid-2019 was the rainiest such span ever recorded nationwide. 2019 alone ended up as one of the top two or three wettest years in over a century of recordkeeping. More rain by itself doesn’t automatically mean fewer clear nights, but it does mean more cloud systems, more storms, and more moisture in the soil evaporating into the sky. Indeed, weather station data have shown a slight uptick in overall cloud cover in various regions. It might be a small change (a few percent more cloudiness on average), but to an astronomer even a small shift can translate into several lost nights that used to be usable.

Beyond the averages, the distribution of weather events has shifted. We now get longer dry spells and longer wet spells, rather than a steady mix. This spells trouble: a long dry spell in summer often coincides with heat and can lead to the aforementioned wildfires, hence a block of completely unusable smoky nights. A long wet spell means week after week of cloud cover. The phrase “when it rains, it pours” has become literally true in the climate sense. So we might go from drought to flooding in the span of a month, but both phases are terrible for astronomy (first everything is on fire, then everything is stormy!).

The anecdotal and community evidence is also compelling. Amateur astronomy clubs and observatories often keep track of how many nights they could open or how many observing sessions got canceled. Many long-time observers have noted a downward trend in clear nights over the past couple decades. For instance, one observer in the Northeast U.S. kept a sky journal from the early 2000s through the 2020s and found that the average number of fully clear nights per month had dropped by a significant margin. “I used to count on at least a dozen good nights in the summer,” he reported, “and now I’m lucky to get 4 or 5.” Another astrophotographer in the Midwest noted that 2022 and 2023 were his worst years in recent memory, “I basically lost the whole spring and summer to weather,” he lamented, citing constant clouds from April through July. Even without scientific instruments, these dedicated amateurs can tell something has changed, because they simply aren’t getting the same opportunities to observe as they did before.

It’s not just hobbyists noticing. Professional observatories are also grappling with climatic changes. Telescopes in places like Mauna Kea, Hawaii, or Cerro Paranal in Chile are situated in historically dry, stable sites. But scientists have projected that by 2050, many of these locations will experience higher temperatures and more water vapor in the atmosphere above them, cutting into their precious clear observing time. In recent years, observatories in California and Australia have even had to evacuate or shut down temporarily due to encroaching wildfires, something virtually unheard of decades ago. The famous Mount Wilson Observatory in Southern California (which once housed the largest telescope in the world) had a close brush with a wildfire in 2020, surviving only because firefighters heroically defended the domes. Kitt Peak in Arizona lost several smaller telescope structures to a wildfire in 2022. These incidents underline that it’s not business as usual for astronomy in a warming world.

One particularly sobering voice comes from a meteorologist who specializes in astronomy weather forecasts. He warned that if current trends continue, clear skies outside of winter may become an endangered phenomenon by the latter half of this century. This isn’t a fanciful prophecy but a logical extrapolation: more heat means more smoke and haze, more moisture means more clouds. We could reach a point where, as he put it, “we won’t see blue sky anymore between March and December.” Imagine that, essentially a permanent haze or film except during the coldest months. That might be a worst-case scenario, but it underscores how dramatically things are trending.

Even now, he notes, the wildfire “season” has extended to absurd lengths. Two decades ago, large wildfires were mostly a late-summer thing, perhaps igniting in July and August and then dying down by early fall. Now, fires are flaring up as early as March and as late as November in some areas. Essentially, the only fire-free (and smoke-free) period left is the heart of winter. This aligns with what many backyard astronomers have informally observed: summer has become one long haze-fest, fall often brings lingering smoke or an early rainy season, and spring is volatile and stormy. That leaves winter as the last refuge of the serious stargazer.

To sum up the data and trends: Yes, the sky conditions today are generally worse for astronomy in many parts of the world than they were 20 years ago. There are more cloudy nights in some regions, and certainly more high-humidity and smoky nights. The decline isn’t uniform, some lucky areas might not have changed much, but the overall pattern is clear enough that both numbers and narratives agree. It’s as if the atmosphere has gotten busier and dirtier, just when our telescopes and cameras have gotten better and more eager to probe the heavens. Mother Nature, it seems, has a bit of a sense of irony.

Looking up through the changes

So, is astronomy becoming a winter sport? In many ways, it is indeed sliding in that direction. If you define “astronomy season” as the times when conditions are favorable, then lots of folks would point to late fall and winter now as the prime window, rather than summer. The stars themselves, of course, haven’t changed, Orion still marches across the January sky and the Milky Way still graces July nights, but our ability to see them is increasingly governed by the quirks of climate and weather. It’s a bit like how baseball is theoretically a summer game, but if every stadium was rained out night after night, you’d start scheduling double-headers in October instead. Stargazing isn’t scheduled by a league, but individually we’re all shifting our “season” to whenever the skies will cooperate, and lately that’s been the cold months.

There’s a measure of poetic justice (or cosmic joke) in this. The winter constellations, Orion, Gemini, Taurus, and the like, have always been there waiting for those willing to brave the cold. Now they’re getting more attention by necessity. And while summer’s treasures like the galactic center or the Perseid meteors aren’t going away, observers are learning to seize the moment for those when a rare clear summer night comes along. In a way, astronomy has become a year-round sport of opportunism: you take what you can get, when you can get it. But the pattern is clear: if you absolutely need good conditions, you plan for winter. It’s telling that some of the biggest star parties and astrophotography gatherings have started to migrate to autumn or early spring, avoiding the height of summer. Twenty years ago, a July star party was a safe bet for clear skies in many states; today, organizers worry about scheduling anything in July or August unless it’s in an historically arid location.

Yet, despite all the challenges, astronomers are a tenacious and optimistic bunch. We adjust. If smoke is an issue, we travel further to find smoke-free air, or even turn to remote observatories in other countries. If summers are cloudy, we emphasize winter observing and use summer for processing data or upgrading equipment (with a bit of grumbling to be sure). And there’s a communal aspect too: nothing bonds a group of stargazers like collectively cursing at a stubborn cloud bank or doing a “clear sky dance” when the forecast looks iffy. In the spirit of Mark Twain, we learn to joke about it, “Maybe the clouds just love us too much”, even as we also face the serious reality that something fundamental is shifting.

One might ask, is there any silver lining (pun intended) to these cloudy trends? Well, perhaps it makes those rare perfect nights even more precious. When you’ve been skunked by weather for months, the first truly clear, dark night that comes along feels almost transcendent. You won’t catch a seasoned astronomer taking a clear night for granted anymore. There’s a renewed appreciation for what used to be more common. In that sense, the hobby is teaching us patience and resilience. It’s also inadvertently raising awareness about climate issues. Amateur astronomers are acutely aware of things like air quality, jet stream patterns, and long-term weather shifts, after all, our hobby depends on the sky. We are often the first to notice and lament, “The sky isn’t as clear as it used to be.” In our own small way, we serve as informal custodians of the sky, adding our voices to the call for taking better care of our atmosphere (because not only is it the only one we have for breathing, it’s also the only window we have to the universe).

In true Mark Twain fashion, one could wryly conclude: reports of the death of summer stargazing have been slightly exaggerated, but not by much. The “lazy summer night under the stars” isn’t extinct, but it has become an increasingly endangered experience, something you might have to chase across states or wait weeks for. Meanwhile, the winter sky, once shunned by many casual observers for its cold, is now the dependable old friend we always suspected it was. It might nip at your nose and make your breath fog up the eyepiece, but it will show you the cosmos in all its glory when others seasons won’t.

Ultimately, astronomy will continue in any season, because our sense of wonder isn’t confined to a schedule. If the universe is putting on a show, we’ll try to watch it, be it July or January. But the trends are unmistakable: the scales are tipping toward winter. So the next time you find yourself shivering under a January sky, count yourself lucky, you’re in the new prime time of amateur astronomy. And when your toes start to go numb, just remember that warm summer night when you were staring at clouds and swatting mosquitoes, and suddenly that winter chill might feel a bit more like an acceptable trade-off. As we adapt to these changing skies, perhaps we’ll also be inspired to care more for our planet’s climate. After all, protecting our clear nights is really about protecting our one and only home, Earth, so that future generations, whether in summer or winter, can still look up and see a sky full of stars.

In the meantime, keep that winter coat handy next to your telescope. It seems you’re going to need it.