What Temperature Is Sweater Weather?

Sweater weather is roughly 50 to 65°F (10 to 18°C): too cool for a T-shirt on its own, not cold enough for a coat. In a 2015 Weather Channel viewer poll the US average was 60°F (16°C), from 65°F (18°C) in Arizona and Nevada down to 51°F (11°C) in South Dakota. Wind and sun can move that line by more than a sweater is actually worth.

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What temperature counts as sweater weather?

The National Weather Service glossary has no entry for it, so the honest evidence is what people say. In a Weather Channel poll of its viewers, reported by the Arizona Daily Star in October 2015, the national average was 60°F. The Weather Company reported in 2024 that the median temperature at which its Weather Channel users say fall gets cool enough for a sweater is highest in the West, at 60°F, and lowest in the Upper Midwest, at 50°F. For context, a July 2014 YouGov poll put Americans' ideal temperature at 72°F (22°C) on average, with "too cold" starting at 37°F (3°C). Sweater weather sits inside that range, where one knit layer is enough.

The line follows climate only at the extremes, with Arizona and Nevada at the top and South Dakota at the bottom. In between it is untidy: Oklahoma sat at 55°F alongside Minnesota and Wisconsin, while Michigan and Wyoming matched Texas at 60°F. In British English the same idea is "jumper weather", and in Celsius the band is about 10 to 18°C.

How many degrees is a sweater actually worth?

Fewer than you might think. ASHRAE Standard 55, the US standard for indoor thermal comfort, rates clothing in "clo" units of insulation: trousers, a long-sleeve shirt and a suit jacket together come to about 1 clo (0.96 in its table). A thin long-sleeve sweater adds about 0.25 clo and a thick one about 0.36 clo. For someone sitting still, each clo lowers the comfortable temperature by about 11°F (6°C), so:

• a thin sweater is worth about 2.8°F (1.5°C), which is ASHRAE's own worked example;
• a thick sweater is worth about 4°F (2.2°C).

ASHRAE's numbers assume you are indoors and near-sedentary, so treat them as an order of magnitude outdoors. The point holds: a sweater buys you a few degrees, not ten. That is why the sweater-only zone is narrow, and why wind and sun often decide more than the number on the forecast.

How do wind, sun and humidity change sweater weather?

Wind bites at the bottom of the band. The National Weather Service wind chill formula starts at 50°F (10°C), for winds above 3 mph. Run it at 50°F with a 15 mph (24 km/h) breeze and the wind chill is 45°F (7°C); at 25 mph (40 km/h) it is 43°F (6°C). Losing 5 to 7°F is more than a thick sweater adds, so on a windy day the useful extra layer is a windbreak. Canada's workplace safety agency, CCOHS, advises an easily removable windbreak garment when you cannot get out of the wind.

Sun pushes the other way. The NWS notes that bright sunshine may increase the wind chill temperature by 10 to 18°F (about 6 to 10°C), because its formula assumes no sun at all. That is several sweaters' worth of warmth, which is why the same temperature can call for different clothes in sun and in shade.

Humidity barely registers officially. The NWS heat index is a hot-weather measure, and even its simple formula for cooler air stays within about 4°F of the thermometer across the sweater band. Environment and Climate Change Canada shows the humidex only from 20°C (68°F). In cool weather the bigger problem is wet clothing: CCOHS notes that cotton gets damp quickly and loses its insulating properties, while wool and synthetic fibers retain heat when wet.

Why does my weather app's "feels like" barely move in sweater weather?

Because for most of the band no official index applies. The rules differ by country:

So across almost the whole band the official US and Canadian numbers add little or nothing to the thermometer reading, and the Met Office lists temperature, humidity and wind as its inputs, not sunshine. On a calm, sunny 58°F afternoon the official "feels like" stays close to 58°F, even though the sun makes it feel warmer; some apps add their own adjustment for sunshine, one reason they disagree. Our guides to how the US measures wind chill and feels like and the Met Office feels-like temperature cover the formulas themselves.

What should you wear in sweater weather?

• Pick the weight by the gap. By ASHRAE's numbers a thin knit covers a couple of degrees and a thick one about 4°F (2°C), so near the top of the band a thin sweater over a T-shirt does the job.
• Layer instead of bulking up. CCOHS advises multiple layers, which protect better than a single thick garment. A thin sweater under a wind-resistant shell covers more of the band than one heavy knit, because the shell comes off when the sun comes out.
• Choose wool or a synthetic knit if rain is possible. Cotton loses its insulation once damp; wool and synthetics keep working.
• Below 50°F the sweater becomes the middle layer. Our layer guide for 40, 50, 60 and 70 degree weather covers what goes over it.

When does sweater weather start in the US?

NOAA's 1991-2020 daily climate normals show when the normal afternoon high first drops below 65°F (18°C), the top of the band, and below 50°F (10°C), the bottom. Between the two dates a typical afternoon sits in sweater range. The dates are for the NOAA station named in each row, mostly airports (Washington is Reagan National), not the city center.

Minneapolis gets about four weeks of sweater afternoons before highs fall below 50°F, while in Atlanta and Dallas the normal high never drops that far, so the season runs right through winter. In Los Angeles and Phoenix the coldest normal highs sit right at 65°F, so sweater weather there is mostly a morning and evening affair: around December 20 the normal low is 48.7°F (9.3°C) at LAX and 44.4°F (6.9°C) in Phoenix.

When does jumper weather start in the UK and Canada?

The Met Office and Environment and Climate Change Canada publish 1991-2020 averages by month. Average daily highs:

In London and Cardiff jumper weather is an October and November affair. Edinburgh and Belfast are already in the band in September, and Edinburgh's warmest month, July, averages only 66.7°F (19.3°C), so a jumper is rarely far away. Canada's window is shorter: October is in the band in all four Canadian cities, Calgary's September average of 64.9°F (18.3°C) is right on the line, and by November every one of them averages below 50°F (10°C).

Is it sweater weather today?

Normals tell you the season; the forecast tells you the day, and forecast models do not always agree on the afternoon high. In sweater weather a gap of a few degrees is about what a sweater is worth, so a forecast of 61°F and one of 67°F point to different clothes. Our city pages for the US, UK and Canada put the main models side by side, so you can see whether tomorrow's high is agreed or argued about, and our methodology page explains how we score each model's daily highs.

Sweater weather is a band, not a number: about 50 to 65°F (10 to 18°C), centered on 60°F (16°C) for most Americans. Inside that band, check the wind and the sun before you choose the knit.