America’s Most Extreme Climates: Where the Temperature Swings Hardest

How Much Each City Swings in a Year, Ranked

Annual temperature swing is the warmest month’s average temperature minus the coldest month’s, with each monthly figure the average of the daily highs and lows. Widest swing first. Interior-continental cities own the top; the Pacific coast, south Florida and Hawaii fill the bottom.

Warmest-minus-coldest monthly average temperature per primary long-record airport station, NOAA GHCN-Daily, 2015–2024, computed on October 11, 2026. Monthly averages are used because they are robust to the odd bad daily reading in the raw archive; all-time single-day records quoted in the text are official NWS station records, cited below.

Two Completely Different Ways to Be “Mild”

The bottom of the list looks uniform — a dozen cities with swings under 18°F — but it hides two opposite climates that happen to land on the same number. A small swing can mean warm all year or cool all year, and the two feel nothing alike.

Honolulu and San Francisco have nearly the same tiny swing, but their actual temperatures sit about 20°F apart. Both achieve steadiness through water — one warm, one cold. That is the opposite of what the continental interior does, where there is no water to hold anything steady. If you want to see how these differences stack up into something livable, we fold year-round comfort into our best-weather states ranking.

Why the Northern Plains Swing Hardest

Below Fairbanks, the top of the ranking is a solid block of the Dakotas, Minnesota and Montana — Minneapolis is the most extreme big metro in the Lower 48 at 56.6°F. The word for it is continentality, and it comes down to one thing these cities don’t have: an ocean nearby.

• Water is a flywheel; the Plains don’t have one. Oceans and large lakes soak up summer heat and give it back slowly through winter, smoothing both ends. A thousand miles from the coast, the land has nothing to buffer it — it heats fast in summer and dumps heat fast in winter.
• Long days, long nights. The farther north you go, the more lopsided the seasons: Fairbanks runs nearly 22 hours of daylight in June and under four in December. That alone stretches the summer-to-winter gap wider than anything a mid-latitude city sees.
• Snow locks in the cold. Once the northern Plains go white, the fresh snow reflects most of the weak winter sun straight back to space and lets the surface radiate heat away on clear nights. Coldest-month averages crash into the teens and single digits — which is exactly where the swing comes from.
• The cold-month lag. For several of these cities — Rapid City, Billings, Great Falls, Havre — the coldest month in our data is February, not January, a sign of how long it takes a buried, snow-covered continent to hit bottom.

The same interior that produces these swings is also where cold air pools deepest — see the coldest cities in America, which is nearly the same roster, and the worst winters in US history.

Why We Rank on the Monthly Average, Not the Record

There is a flashier way to measure a wild climate: the gap between a city’s all-time record high and its all-time record low. By that measure Fairbanks is staggering — an official 96°F (June 15, 1969) down to −66°F (January 14, 1934), a range of about 162°F. Hilo’s official records run from 94°F (2013) to 53°F (1962) — a range of just 41°F.

We don’t rank on record range, for two reasons. First, a single freak day — one 1930s cold snap, one once-a-century heat spike — can decide it, so it measures luck as much as climate. Second, the raw daily archive carries the occasional bad reading (a tropical station does not actually hit −40°F), and a record-high-minus-record-low metric would swallow those errors whole. A warmest-month-minus-coldest-month average is the honest answer to “how different are this city’s seasons,” and it survives a bad day in the data untouched. The record figures above are official NWS station records, which run longer than our 1970-onward archive — that is why Fairbanks’ −66°F (1934) predates our window.

Frequently Asked Questions

Keep Exploring

This is the temperature chapter of our US city-climate series. See which places get the most wind in the windiest cities in America, the most sky in the sunniest and cloudiest cities, and the muggiest air in the most humid cities. For the raw extremes, there are the hottest states and cities and the coldest cities. Or look up the real temperature on any day in Anchorage, Honolulu or your own town with our weather-history tool. If your local gauge shows a wider swing than the ones here, tell us — browse the rest at our weather records.

Sources & Method

Temperature-swing figures are computed from the site’s Neon copy of NOAA’s Global Historical Climatology Network–Daily archive. For each city we took its primary long-record airport station, averaged the daily high and low for every month over 2015–2024, and subtracted the coldest month’s average from the warmest month’s — pulled and ranked on October 11, 2026. Monthly means are used rather than single-day extremes because they are robust to erroneous daily values in the raw archive. All-time single-day records are official National Weather Service station records: Fairbanks’ 96°F (June 15, 1969) and −66°F (January 14, 1934), and Hilo’s 94°F (November 28, 2013) and 53°F (February 21, 1962), both of which predate or extend beyond our 1970-onward archive. See our data sources & methodology for how these figures are compiled.