St. Catharines climate
St. Catharines (Ontario, Canada) has a hot-summer humid continental climate (Köppen Dfa). The average temperature over the year is 10 °C50 °F, and about 872 mm34 in of precipitation falls in an average year.
Temperature by month
Precipitation by month
St. Catharines climate table
| Month | High °C°F | Low °C°F | Mean °C°F | Precip. mmin | Frost days |
|---|---|---|---|---|---|
| Jan | 032 | −522 | −327 | 592.3 | 27 |
| Feb | 033 | −622 | −327 | 512.0 | 26 |
| Mar | 540 | −228 | 134 | 582.3 | 23 |
| Apr | 1151 | 236 | 744 | 753.0 | 8 |
| May | 1763 | 948 | 1356 | 813.2 | 0 |
| Jun | 2374 | 1559 | 1966 | 803.2 | 0 |
| Jul | 2780 | 1966 | 2373 | 873.4 | 0 |
| Aug | 2679 | 1966 | 2272 | 712.8 | 0 |
| Sep | 2373 | 1559 | 1966 | 813.2 | 0 |
| Oct | 1560 | 948 | 1254 | 893.5 | 0 |
| Nov | 948 | 337 | 643 | 702.8 | 7 |
| Dec | 337 | −229 | 133 | 702.8 | 22 |
| Year | 2780 | −622 | 1050 | 87234 | 113 |
“Year” row: highest monthly high, lowest monthly low, annual mean and annual total. Frost days are for the whole grid cell.
| Month | Humid. | Cloud | Solar | Daylight |
|---|---|---|---|---|
| Jan | 86% | 81% | 1.4 | 9:19 |
| Feb | 85% | 78% | 2.1 | 10:27 |
| Mar | 82% | 74% | 3.4 | 11:48 |
| Apr | 79% | 75% | 4.5 | 13:21 |
| May | 78% | 74% | 5.5 | 14:39 |
| Jun | 75% | 68% | 6.1 | 15:22 |
| Jul | 71% | 64% | 6.0 | 15:04 |
| Aug | 71% | 62% | 5.3 | 13:56 |
| Sep | 73% | 60% | 4.2 | 12:26 |
| Oct | 78% | 74% | 2.5 | 10:56 |
| Nov | 81% | 75% | 1.6 | 9:38 |
| Dec | 85% | 81% | 1.2 | 8:00 |
Humid. = average relative humidity at 2 m; cloud = average cloud amount; solar = average daily solar energy reaching the ground in kWh/m² (all-sky); daylight in hours:minutes, calculated for the 15th of each month.
What the climate of St. Catharines is like
The warmest month is July, with an average high of 27 °C80 °F and a low of 19 °C66 °F. The coldest is January, when highs average 0 °C32 °F and lows −5 °C22 °F. Seasons are strongly marked: the warmest month is on average 25.5 °C46 °F warmer than the coldest.
Annual precipitation is moderate at about 872 mm34 in. Rain is spread fairly evenly through the year. The wettest month is October (89 mm3.5 in), the driest is February (51 mm2.0 in).
Relative humidity ranges from 71% in August to 86% in January. The clearest skies (lowest average cloud amount, 60%) are typical of September. Average wind speed near the ground ranges from 10 km/h (6 mph) in June to 18 km/h (11 mph) in January. Daylight lasts from about 9.0 hours in December to 15.4 hours in June.
A lasting snow cover is typical in December–March, when the average snow depth in the reanalysis exceeds 10 cm (deepest in January, about 17 cm).
Best time to visit St. Catharines
Based on these averages, the most comfortable months for sightseeing and outdoor activities are June–September: average highs of 23 °C73 °F to 27 °C80 °F with 71 mm2.8 in to 87 mm3.4 in of precipitation per month.
The most challenging month is January, which is cold, with average highs of 0 °C32 °F.
Comfort score: months are ranked by how close they come to an average high of 21–28 °C (70–82 °F), lows above 5 °C (41 °F), little precipitation and moderate humidity. The best-ranked months of each place are recommended, even where none meets all of these. These are general rules of thumb applied to long-term averages.
What to pack for St. Catharines
- Winter (December–February) — highs 032 to 3 °C37 °F, lows −622 to −2 °C29 °F, about 60 mm2.4 in of precipitation a month. Pack a winter coat, hat, gloves and warm, non-slip boots and shoes with good grip, as frost is common.
- Spring (March–May) — highs 540 to 17 °C63 °F, lows −228 to 9 °C48 °F, about 71 mm2.8 in of precipitation a month. Pack a warm coat, layers and closed shoes.
- Summer (June–August) — highs 2374 to 27 °C80 °F, lows 1559 to 19 °C66 °F, about 79 mm3.1 in of precipitation a month. Pack light summer clothes such as T-shirts, shorts or light dresses.
- Autumn (September–November) — highs 948 to 23 °C73 °F, lows 337 to 15 °C59 °F, about 80 mm3.2 in of precipitation a month. Pack long sleeves, a sweater and a medium jacket.
How St. Catharines compares
Compared with Buffalo, about 43 km to the southeast, St. Catharines is on average 0.5 °C0.9 °F warmer and receives 8% less precipitation (872 mm34 in vs 947 mm37 in). The difference is largest in December (1.1 °C2 °F warmer).
Of the 40 places in Canada covered by World Climates, St. Catharines is the 7th warmest by annual mean temperature and the 18th wettest by annual precipitation. See all of them on the Canada climate page.
Places in other countries with the most similar temperature and rainfall pattern: Buffalo (United States, Dfa), Cleveland (United States, Dfa) and Chicago (United States, Dfa).
Nearby places
- Buffalo 43 km · 9 °C49 °F · 947 mm37 in
- Toronto 61 km · 9 °C48 °F · 774 mm30 in
- Brampton 71 km · 8 °C47 °F · 770 mm30 in
- Ajax 77 km · 9 °C48 °F · 719 mm28 in
- Markham 77 km · 8 °C47 °F · 723 mm28 in
- Brantford 83 km · 9 °C48 °F · 791 mm31 in
- Oshawa 87 km · 9 °C47 °F · 719 mm28 in
- Guelph 92 km · 8 °C46 °F · 770 mm30 in
Frequently asked questions
What is the warmest month in St. Catharines?
July is the warmest month in St. Catharines, with an average high of 27 °C (80 °F) and an average low of 19 °C (66 °F).
What is the coldest month in St. Catharines?
January is the coldest month, with an average high of 0 °C (32 °F) and an average low of -5 °C (22 °F).
When does it rain the most in St. Catharines?
October is the wettest month with about 89 mm (3.5 in) of precipitation; February is the driest with about 51 mm (2.0 in).
What is the best time to visit St. Catharines?
Judging by long-term averages, the most comfortable months are June–September.
About this data
All figures are 25-year averages (January 2001 – December 2025) from the NASA POWER project. Temperature, humidity, wind and precipitation come from the MERRA-2 reanalysis (precipitation is the bias-corrected MERRA-2 product), cloud and solar values from CERES satellite data. They describe a grid cell of roughly 50–70 km, not a single weather station, so they can differ from airport records — most of all on coasts, in mountains and for rainfall. Average highs and lows are the monthly mean temperature plus/minus half of the average daily temperature range. Counts of rainy days are not part of this dataset.
The grid cell’s average elevation is 163 m, while St. Catharines lies at about 102 m. Temperatures on this page were therefore adjusted by +0.4 °C0.7 °F using the standard lapse rate of 6.5 °C per 1,000 m.