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Berwyn, Illinois climate
Dfa Hot-summer humid continental
Berwyn has a strongly seasonal cool-temperate climate (Hot-summer humid continental, Köppen Dfa). The hottest month is July with an average daily high near 32°C, while the coldest is January averaging around −10°C at night. Around 1051 mm of precipitation falls each year, peaking in May (126 mm) and easing off in February (51 mm).
Temperature & precipitation
Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figuresClear vs cloudy days
Share of days each month that are clear, partly cloudy or cloudy · 1991–2020 · hover a month for the day countsBerwyn climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 1 | 3 | 9 | 17 | 23 | 29 | 32 | 30 | 27 | 18 | 10 | 3 |
| Avg temp (°C) | −5 | −3 | 4 | 10 | 16 | 22 | 25 | 24 | 20 | 12 | 5 | −1 |
| Avg low (°C) | −10 | −8 | −2 | 4 | 10 | 15 | 18 | 17 | 13 | 6 | 0 | −6 |
| Precipitation (mm) | 58 | 51 | 64 | 105 | 126 | 118 | 104 | 113 | 88 | 93 | 69 | 61 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°C) | 1 | 3 | 9 | 17 | 23 | 29 |
| Avg temp (°C) | −5 | −3 | 4 | 10 | 16 | 22 |
| Avg low (°C) | −10 | −8 | −2 | 4 | 10 | 15 |
| Precipitation (mm) | 58 | 51 | 64 | 105 | 126 | 118 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°C) | 32 | 30 | 27 | 18 | 10 | 3 |
| Avg temp (°C) | 25 | 24 | 20 | 12 | 5 | −1 |
| Avg low (°C) | 18 | 17 | 13 | 6 | 0 | −6 |
| Precipitation (mm) | 104 | 113 | 88 | 93 | 69 | 61 |
How often — frequency of weather events
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 9 | 8 | 9 | 11 | 13 | 12 | 10 | 10 | 8 | 10 | 9 | 10 |
| Days with high ≥ 32°C (days) | — | — | — | — | 0.7 | 3 | 4 | 3 | 1 | — | — | — |
| Days with low ≤ 0°C (days) | 9 | 8 | 7 | 2 | 0.1 | — | — | — | — | 0.9 | 4 | 8 |
| Days with snowfall ≥ 2.5 cm (days) | 3 | 3 | 1 | 0.3 | — | — | — | — | — | 0.1 | 0.4 | 2 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 9 | 8 | 9 | 11 | 13 | 12 |
| Days with high ≥ 32°C (days) | — | — | — | — | 0.7 | 3 |
| Days with low ≤ 0°C (days) | 9 | 8 | 7 | 2 | 0.1 | — |
| Days with snowfall ≥ 2.5 cm (days) | 3 | 3 | 1 | 0.3 | — | — |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 10 | 10 | 8 | 10 | 9 | 10 |
| Days with high ≥ 32°C (days) | 4 | 3 | 1 | — | — | — |
| Days with low ≤ 0°C (days) | — | — | — | 0.9 | 4 | 8 |
| Days with snowfall ≥ 2.5 cm (days) | — | — | — | 0.1 | 0.4 | 2 |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 70 | 70 | 69 | 67 | 66 | 59 | 52 | 51 | 50 | 60 | 67 | 70 |
| Clear days (≤ 30% cloud) | 3 | 3 | 4 | 5 | 5 | 6 | 8 | 9 | 10 | 8 | 4 | 3 |
| Partly cloudy days (30–70%) | 11 | 10 | 10 | 9 | 10 | 11 | 14 | 12 | 10 | 9 | 9 | 9 |
| Cloudy days (≥ 70%) | 17 | 16 | 17 | 16 | 17 | 13 | 9 | 10 | 10 | 14 | 17 | 18 |
| Relative humidity (%) | 86 | 83 | 79 | 76 | 76 | 77 | 76 | 74 | 72 | 74 | 80 | 86 |
| Wind speed (mph) | 8.6 | 8.5 | 8.6 | 8.6 | 7.3 | 5.9 | 5.1 | 4.9 | 5.7 | 7.0 | 7.9 | 7.9 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 70 | 70 | 69 | 67 | 66 | 59 |
| Clear days (≤ 30% cloud) | 3 | 3 | 4 | 5 | 5 | 6 |
| Partly cloudy days (30–70%) | 11 | 10 | 10 | 9 | 10 | 11 |
| Cloudy days (≥ 70%) | 17 | 16 | 17 | 16 | 17 | 13 |
| Relative humidity (%) | 86 | 83 | 79 | 76 | 76 | 77 |
| Wind speed (mph) | 8.6 | 8.5 | 8.6 | 8.6 | 7.3 | 5.9 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 52 | 51 | 50 | 60 | 67 | 70 |
| Clear days (≤ 30% cloud) | 8 | 9 | 10 | 8 | 4 | 3 |
| Partly cloudy days (30–70%) | 14 | 12 | 10 | 9 | 9 | 9 |
| Cloudy days (≥ 70%) | 9 | 10 | 10 | 14 | 17 | 18 |
| Relative humidity (%) | 76 | 74 | 72 | 74 | 80 | 86 |
| Wind speed (mph) | 5.1 | 4.9 | 5.7 | 7.0 | 7.9 | 7.9 |
Methodology & sources
Temperature & precipitation — the official 1991–2020 climate normals from NOAA's U.S. Climate Normals, measured at Little Red School House (NOAA GHCN station USC00115110), about 17 km from the city centre.
Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.