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St. Catharines, Ontario climate
Cfa Humid subtropical
St. Catharines has a seasonal cool-temperate climate (Humid subtropical, Köppen Cfa). The hottest month is July with an average daily high near 79°F, while the coldest is January averaging around 22°F at night. Around 27 inches of precipitation falls each year, peaking in June (3.1 inches) and easing off in February (1.4 inches).
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)St. Catharines climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°F) | 33 | 34 | 40 | 51 | 62 | 72 | 79 | 78 | 72 | 59 | 48 | 38 |
| Avg temp (°F) | 28 | 28 | 35 | 44 | 55 | 66 | 72 | 72 | 66 | 54 | 43 | 34 |
| Avg low (°F) | 22 | 23 | 29 | 38 | 48 | 59 | 66 | 66 | 59 | 48 | 38 | 29 |
| Precipitation (in) | 1.8 | 1.4 | 1.7 | 2.9 | 2.6 | 3.1 | 2.4 | 2.1 | 2.6 | 2.4 | 2.1 | 1.7 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°F) | 33 | 34 | 40 | 51 | 62 | 72 |
| Avg temp (°F) | 28 | 28 | 35 | 44 | 55 | 66 |
| Avg low (°F) | 22 | 23 | 29 | 38 | 48 | 59 |
| Precipitation (in) | 1.8 | 1.4 | 1.7 | 2.9 | 2.6 | 3.1 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°F) | 79 | 78 | 72 | 59 | 48 | 38 |
| Avg temp (°F) | 72 | 72 | 66 | 54 | 43 | 34 |
| Avg low (°F) | 66 | 66 | 59 | 48 | 38 | 29 |
| Precipitation (in) | 2.4 | 2.1 | 2.6 | 2.4 | 2.1 | 1.7 |
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 (mph) | 12.5 | 11.8 | 10.1 | 8.7 | 6.7 | 6.4 | 6.6 | 6.8 | 8.0 | 9.6 | 10.5 | 11.6 |
| 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 (mph) | 12.5 | 11.8 | 10.1 | 8.7 | 6.7 | 6.4 |
| 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 (mph) | 6.6 | 6.8 | 8.0 | 9.6 | 10.5 | 11.6 |
Methodology & sources
Temperature & precipitation — 1991–2020 normals computed from 25 years of daily observations at Port Weller (aut), a weather station, about 9 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.