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Aarau, Switzerland climate
Cfb Oceanic / temperate
Aarau has a seasonal cool-temperate climate (Oceanic / temperate, Köppen Cfb). The hottest month is July with an average daily high near 78°F, while the coldest is January averaging around 29°F at night. Precipitation is fairly even year-round, totalling about 36 inches.
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Summers
Warm
Highs near 78°F in July.
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Winters
Cold
Lows near 29°F in January.
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Rain
Moderate rainfall
About 36 in of rain a year.
Wettest in May
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Sky & trend
Often cloudy
Cloudy skies much of the year.
Temperature & precipitation
Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figuresHours of sunshine per day
Estimated sunny hours each month — daylight length × clear-sky fraction · 1991–2020 monthly cloud cover (NASA POWER)Aarau climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°F) | 39 | 43 | 52 | 60 | 67 | 74 | 78 | 77 | 68 | 58 | 46 | 40 |
| Avg temp (°F) | 34 | 35 | 43 | 50 | 57 | 64 | 67 | 66 | 58 | 50 | 41 | 35 |
| Avg low (°F) | 29 | 29 | 34 | 40 | 47 | 54 | 56 | 56 | 50 | 44 | 36 | 31 |
| Precipitation (in) | 2.5 | 2.1 | 2.4 | 2.5 | 3.9 | 3.6 | 3.9 | 3.9 | 2.7 | 2.8 | 2.7 | 3.2 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°F) | 39 | 43 | 52 | 60 | 67 | 74 |
| Avg temp (°F) | 34 | 35 | 43 | 50 | 57 | 64 |
| Avg low (°F) | 29 | 29 | 34 | 40 | 47 | 54 |
| Precipitation (in) | 2.5 | 2.1 | 2.4 | 2.5 | 3.9 | 3.6 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°F) | 78 | 77 | 68 | 58 | 46 | 40 |
| Avg temp (°F) | 67 | 66 | 58 | 50 | 41 | 35 |
| Avg low (°F) | 56 | 56 | 50 | 44 | 36 | 31 |
| Precipitation (in) | 3.9 | 3.9 | 2.7 | 2.8 | 2.7 | 3.2 |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 69 | 69 | 68 | 67 | 69 | 65 | 60 | 60 | 62 | 68 | 72 | 72 |
| Relative humidity (%) | 89 | 86 | 82 | 79 | 78 | 78 | 77 | 78 | 81 | 85 | 89 | 89 |
| Wind speed (mph) | 4.9 | 5.1 | 5.2 | 4.4 | 4.3 | 4.0 | 3.9 | 3.4 | 3.8 | 4.0 | 4.0 | 4.8 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 69 | 69 | 68 | 67 | 69 | 65 |
| Relative humidity (%) | 89 | 86 | 82 | 79 | 78 | 78 |
| Wind speed (mph) | 4.9 | 5.1 | 5.2 | 4.4 | 4.3 | 4.0 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 60 | 60 | 62 | 68 | 72 | 72 |
| Relative humidity (%) | 77 | 78 | 81 | 85 | 89 | 89 |
| Wind speed (mph) | 3.9 | 3.4 | 3.8 | 4.0 | 4.0 | 4.8 |
Methodology & sources
Temperature & precipitation — the official 1991–2020 climate normals from a national meteorological service, measured at Buchs / Aarau, about 3 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.