The US Cities Where Winter Is Warming Fastest, Ranked
Winter is America's fastest-warming season — and in Milwaukee, the average winter is now 5.6°F warmer than it was in the early 1970s. We pulled 139 million NOAA daily temperature records to rank 27 major cities by how much their winters have heated up, which ones lost the most freezing nights, and the one big city where winter hasn't budged at all.
Winter Is Heating Up Faster Than Summer — in Most of the Country
Here is the finding that surprised us most. We compared winter and summer warming for the same 27 cities over the same two periods, and winter warmed faster than summer in 21 of them. That matches what NOAA and Climate Central have found nationally: winter was the fastest-warming season for 76% (185) of the 245 US locations Climate Central analyzed since 1970, clustered in the Northeast, Southeast, and Ohio Valley (Climate Central, Jan 22 2025).
To rank the cities, I pulled every December, January, and February daily temperature from NOAA's GHCN-Daily dataset for each city's long-record airport station, then compared the 1970–1984 average against the 2010–2024 average — two clean 15-year windows, roughly 1,350 daily readings per city per window. The “change” column is the shift in the average daily temperature; I tracked overnight lows and freezing nights separately because that's where the winter signal is loudest.
Two patterns jump out. First, the 9 Midwestern cities dominate the top of the list — cold-continental winters are warming fastest, exactly as the physics predicts (regions that spend more of the season near freezing gain the most as the baseline shifts up). Second, the six cities where summer out-warmed winter are all in the arid or mountain West — Denver, Salt Lake City, Boise, Seattle, Las Vegas, and Phoenix. Out West, it's the summers doing the heavy lifting; east of the Rockies, it's the winters.
27 US Cities, Ranked by Winter Warming
December–February average temperature, 1970–1984 vs 2010–2024, from our NOAA GHCN-Daily database. “Nights lost” is the change in freezing nights (below 32°F) per winter — a negative value means the city gained freezing nights.
| # | City | 70s Avg | Now | Change | Overnight Low | Freezing Nights |
|---|---|---|---|---|---|---|
| 1 | MilwaukeeWI | 21.8°F | 27.5°F | +5.6°F | +6.0°F | 8 fewer |
| 2 | St. LouisMO | 31.3°F | 36.1°F | +4.9°F | +5.1°F | 12 fewer |
| 3 | FargoND | 9.1°F | 13.9°F | +4.8°F | +5.0°F | 2 fewer |
| 4 | AtlantaGA | 43.5°F | 48°F | +4.6°F | +5.5°F | 18 fewer |
| 5 | PhiladelphiaPA | 33.3°F | 37.6°F | +4.3°F | +4.6°F | 13 fewer |
| 6 | ClevelandOH | 27.6°F | 31.9°F | +4.3°F | +4.9°F | 9 fewer |
| 7 | LouisvilleKY | 34.9°F | 39°F | +4.2°F | +4.5°F | 13 fewer |
| 8 | ColumbusOH | 29.2°F | 33.3°F | +4.1°F | +4.3°F | 8 fewer |
| 9 | Des MoinesIA | 22.6°F | 26.7°F | +4.0°F | +4.0°F | 4 fewer |
| 10 | IndianapolisIN | 28.4°F | 32.3°F | +3.9°F | +4.3°F | 7 fewer |
| 11 | PittsburghPA | 28.7°F | 32.4°F | +3.7°F | +3.8°F | 6 fewer |
| 12 | Las VegasNV | 47.4°F | 50.9°F | +3.6°F | +5.8°F | 17 fewer |
| 13 | NashvilleTN | 39.2°F | 42.6°F | +3.4°F | +3.8°F | 11 fewer |
| 14 | DetroitMI | 27.1°F | 30.4°F | +3.3°F | +2.8°F | 11 fewer |
| 15 | New York CityNY | 33.9°F | 37.1°F | +3.2°F | +3.4°F | 11 fewer |
| 16 | Oklahoma CityOK | 38.1°F | 41°F | +2.9°F | +2.8°F | 6 fewer |
| 17 | DallasTX | 47.1°F | 49.9°F | +2.8°F | +3.4°F | 11 fewer |
| 18 | BostonMA | 31.2°F | 33.9°F | +2.7°F | +2.9°F | 7 fewer |
| 19 | BaltimoreMD | 35°F | 37.7°F | +2.7°F | +2.4°F | 4 fewer |
| 20 | MemphisTN | 42.2°F | 44.9°F | +2.7°F | +2.7°F | 9 fewer |
| 21 | CincinnatiOH | 32.6°F | 35.2°F | +2.5°F | +2.1°F | 3 fewer |
| 22 | AlbuquerqueNM | 36.7°F | 39.1°F | +2.3°F | +3.9°F | 14 fewer |
| 23 | PhoenixAZ | 55.8°F | 58°F | +2.2°F | +3.4°F | 3 fewer |
| 24 | Salt Lake CityUT | 31.6°F | 33.5°F | +1.9°F | +2.8°F | 2 fewer |
| 25 | BoiseID | 32.1°F | 33.9°F | +1.8°F | +2.0°F | 3 more |
| 26 | SeattleWA | 41.5°F | 42.5°F | +1.0°F | +1.0°F | 4 fewer |
| 27 | DenverCO | 31.7°F | 31.8°F | +0.1°F | +0.0°F | 3 more |
Source: NOAA GHCN-Daily, WeatherOnThisDay analysis. December–February daily temperatures, 1970–1984 vs 2010–2024, per primary airport station. Kansas City is omitted — its early-1970s station record is too incomplete for a reliable comparison.
Cite this data
According to WeatherOnThisDay's analysis of NOAA GHCN-Daily records, winter warmed faster than summer in 21 of 27 major US cities between the early 1970s and the early 2020s, led by Milwaukee, whose average winter temperature rose 5.6°F. The steepest everyday change was in Atlanta, which now averages 18 fewer nights below freezing each winter.
The Cities Worth a Closer Look
The single fastest-warming winter of any major US city in our data. Milwaukee's average winter day is now 5.6°F warmer than in the early 1970s, and its overnight lows rose even faster — up 6.0°F. Lake Michigan, slower to freeze in warmer years, keeps feeding milder air onshore well into January.
Fargo is still brutally cold — the average winter runs below 14°F — but the deep freeze has eased by nearly 5°F. Because its baseline is so far below freezing, the milder winters barely dent the freezing-night count: 88 of 90 winter nights still drop below 32°F.
The most dramatic shift in everyday experience on this list. Atlanta now averages 18 fewer freezing nights per winter than in the early 1970s — down from 39 to 21. Hard freezes that once reliably killed garden pests and set peach chill hours are becoming the exception.
The Western exception. Most desert cities warmed more in summer, but Las Vegas winters heated up sharply — overnight lows are up 5.8°F, and freezing nights fell from 21 per winter to just 4. Explosive suburban growth and asphalt sprawl since 1970 built an urban heat island that lingers overnight.
Maritime air keeps Seattle's winters mild and stable. The change is real but the smallest on the list — the Pacific acts as a giant thermal buffer, damping both warming and cooling.
The genuine outlier. Denver's winters are essentially flat — the average is up a statistically meaningless 0.1°F, overnight lows are unchanged, and the city actually averages about 3 MORE freezing nights per winter than in the early 1970s. High-plains winters governed by downslope chinook winds and Arctic outbreaks off the Front Range have not followed the national trend.
Why the Nights Are Warming Fastest
Look down the “Overnight Low” column and you'll see it: in most of these cities, the coldest hours warmed faster than the daily average. Milwaukee's winter lows are up 6.0°F, Las Vegas 5.8°F, Atlanta 5.5°F. That's not a coincidence — it's the fingerprint of a greenhouse-driven climate. Heat-trapping gases and added water vapor act most powerfully at night, when the ground would otherwise radiate its warmth back out to space. Climate Central puts the national gap at roughly 25%: US overnight lows have warmed about a quarter faster than daytime highs since 1900.
Fewer freezing nights sounds pleasant, and for heating bills it can be. But it reshapes a lot of quiet machinery. Milder winters let tree-killing pests like the mountain pine beetle and the hemlock woolly adelgid survive further north. Fruit and nut trees that need a set number of “chill hours” below 45°F to bloom — peaches in Georgia, cherries and almonds out West — increasingly fall short. And a winter that spends less time frozen means more precipitation falls as rain instead of snow, which matters for the snowpack that feeds Western reservoirs through summer.
The Cities That Bucked the Trend
Not every city followed the script. Denver is the standout: its average winter is up a statistically meaningless 0.1°F, its overnight lows are flat, and it now averages about 3 more freezing nights per winter than in the early 1970s. Denver's high-plains winters swing on downslope chinook winds off the Front Range and Arctic air spilling down from Canada — local machinery that hasn't tracked the broader warming. Boise shows a milder version of the same, gaining a few freezing nights while its summers warmed sharply.
Seattle barely moved for the opposite reason: the Pacific is a giant thermal buffer that damps both warming and cooling, so its winters changed the least of any city on the list (+1.0°F). It's the cold-continental interior — not the coasts — where winter is transforming fastest.
Data Sources & Methodology
- First-party: NOAA GHCN-Daily station records in our database (139M readings). Winter defined as December, January, and February daily temperatures at each city's primary long-record airport station. Averages computed for 1970–1984 and 2010–2024. Overnight low = average daily minimum; freezing nights = nights with a low below 32°F. Impossible readings (outside −60°F to 140°F) were filtered out. Kansas City was excluded for incomplete early-period coverage.
- National context: Climate Central, “Fastest-Warming Seasons” (Jan 22, 2025) and “Winter Warming.”
Frequently Asked Questions
Which US city has the fastest-warming winters?
Milwaukee, Wisconsin. Our analysis of NOAA GHCN-Daily records shows Milwaukee's average winter (December–February) temperature rose 5.6°F between 1970–1984 and 2010–2024 — the largest increase of any major US city we measured. Its overnight lows warmed even faster, up 6.0°F.
Is winter warming faster than summer in the United States?
For most cities, yes. In our comparison of identical 15-year periods, winter warmed faster than summer in 21 of 27 major US cities. Climate Central reached the same conclusion nationally: winter was the fastest-warming season for 76% (185) of 245 US locations it analyzed since 1970. The exceptions cluster in the arid and mountain West, where summers are heating up fastest.
How many fewer freezing nights do US cities get now?
It varies widely by city. Atlanta lost the most in our data — 18 fewer nights below 32°F per winter (down from 39 to 21). Las Vegas lost 17 and Albuquerque 14. Climate Central found that 210 US locations now average about 15 fewer freezing nights per year than in the early 1970s. A few high-elevation cities, like Denver and Boise, actually gained a handful of freezing nights.
Why are winter nights warming faster than winter days?
Greenhouse gases trap heat most effectively overnight, when the ground would otherwise radiate warmth back to space, and increased water vapor and cloud cover blanket that heat in. Climate Central reports US overnight lows have warmed about 25% faster than daytime highs since 1900. In our data, winter overnight lows rose faster than the daily average in most cities — Milwaukee (+6.0°F) and Las Vegas (+5.8°F) among the sharpest.
Which US city has NOT seen its winters warm?
Denver, Colorado. Its average winter temperature is essentially unchanged since the early 1970s (+0.1°F), its overnight lows are flat, and it averages about 3 more freezing nights per winter now. High-plains winters driven by downslope chinook winds and Arctic outbreaks off the Front Range have bucked the national warming trend.
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