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Bolton, Ontario climate
Dfb Warm-summer humid continental
Bolton has a strongly seasonal cool-temperate climate (Warm-summer humid continental, Köppen Dfb). The hottest month is July with an average daily high near 27°C, while the coldest is January averaging around −9°C at night. Precipitation is fairly even year-round, totalling about 791 mm. Winters bring significant snowfall (109 cm of snow per year on average).
Temperature & precipitation
Daily high–low temperature range with the monthly average, plus monthly precipitation split into rain and snow · 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)Bolton climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | −1 | 0 | 5 | 12 | 19 | 25 | 27 | 26 | 22 | 15 | 8 | 2 |
| Avg temp (°C) | −5 | −4 | 1 | 7 | 14 | 19 | 22 | 21 | 17 | 10 | 4 | −2 |
| Avg low (°C) | −9 | −8 | −4 | 2 | 8 | 14 | 16 | 16 | 11 | 5 | 0 | −5 |
| Precipitation (mm) | 58 | 48 | 49 | 76 | 78 | 75 | 75 | 68 | 71 | 64 | 72 | 57 |
| Snowfall (cm) | 30 | 25 | 18 | 5 | 0 | — | — | — | — | 0 | 8 | 24 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°C) | −1 | 0 | 5 | 12 | 19 | 25 |
| Avg temp (°C) | −5 | −4 | 1 | 7 | 14 | 19 |
| Avg low (°C) | −9 | −8 | −4 | 2 | 8 | 14 |
| Precipitation (mm) | 58 | 48 | 49 | 76 | 78 | 75 |
| Snowfall (cm) | 30 | 25 | 18 | 5 | 0 | — |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°C) | 27 | 26 | 22 | 15 | 8 | 2 |
| Avg temp (°C) | 22 | 21 | 17 | 10 | 4 | −2 |
| Avg low (°C) | 16 | 16 | 11 | 5 | 0 | −5 |
| Precipitation (mm) | 75 | 68 | 71 | 64 | 72 | 57 |
| Snowfall (cm) | — | — | — | 0 | 8 | 24 |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 78 | 74 | 73 | 73 | 72 | 67 | 63 | 62 | 62 | 72 | 75 | 77 |
| Relative humidity (%) | 86 | 84 | 80 | 78 | 77 | 75 | 73 | 73 | 74 | 78 | 81 | 84 |
| Wind speed (m/s) | 5.6 | 5.3 | 4.5 | 3.9 | 3.0 | 2.9 | 2.9 | 3.1 | 3.6 | 4.3 | 4.7 | 5.2 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 78 | 74 | 73 | 73 | 72 | 67 |
| Relative humidity (%) | 86 | 84 | 80 | 78 | 77 | 75 |
| Wind speed (m/s) | 5.6 | 5.3 | 4.5 | 3.9 | 3.0 | 2.9 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 63 | 62 | 62 | 72 | 75 | 77 |
| Relative humidity (%) | 73 | 73 | 74 | 78 | 81 | 84 |
| Wind speed (m/s) | 2.9 | 3.1 | 3.6 | 4.3 | 4.7 | 5.2 |
Methodology & sources
Temperature & precipitation — 1991–2020 normals computed from 22 years of daily observations at Toronto Lester B. Pearson Int'l A, a weather station, about 24 km from the city centre. The underlying daily records come from NOAA's global station network.
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.