St. Thomas Climate by Month
St. Thomas, Ontario, Canada
Warm summers and freezing winters, with rain spread through the year.
Warm summers and freezing winters, with rain spread through the year: that's St. Thomas's climate in short. Expect highs of 80°F (26°C) in July and 30°F (-1°C) in January, with the coldest nights (January) near 17°F (-8°C). It gets 39 in (982 mm) of rain a year, spread across the months. The air is humid, averaging 79% relative humidity.
- Warmest month
- 80°F(26°C)
- Average high, July
- Coldest nights
- 17°F(-8°C)
- Average low, January
- Rain per year
- 39 in(982 mm)
- No clear rainy season
- Humidity
- 79%
- Sunniest: July
Best and worst months in St. Thomas
Best for weatherJune, August and September are the best time for weather in St. Thomas: highs near 75°F (24°C) and about 3.3 in (84 mm) of rain a month.
Least pleasantJanuary is the least pleasant month: it's the coldest, with highs of only 30°F (-1°C).
Comfort combines how close the afternoon high is to 75°F (24°C) with how much rain falls and how humid it is. See where the weather is best in June.
Temperature and rain through the year
Highs and lows (°F)
Average highAverage low
Rain (in per month)
St. Thomas weather by month
| Month | High | Low | Rain | Humidity | Sun |
|---|---|---|---|---|---|
| JanJanuary | 30°F(-1°C) | 17°F(-8°C) | 3.0 in(77 mm) | 92% | 1.4 |
| FebFebruary | 32°F(0°C) | 17°F(-8°C) | 2.6 in(66 mm) | 89% | 2.3 |
| MarMarch | 41°F(5°C) | 26°F(-3°C) | 2.6 in(66 mm) | 77% | 3.4 |
| AprApril | 54°F(12°C) | 36°F(2°C) | 3.5 in(88 mm) | 69% | 4.4 |
| MayMay | 66°F(19°C) | 46°F(8°C) | 3.6 in(92 mm) | 71% | 5.3 |
| JunJuneBest | 75°F(24°C) | 56°F(13°C) | 3.6 in(92 mm) | 75% | 5.9 |
| JulJuly | 80°F(26°C) | 60°F(16°C) | 3.1 in(80 mm) | 72% | 6.0 |
| AugAugustBest | 78°F(26°C) | 59°F(15°C) | 3.1 in(78 mm) | 75% | 5.2 |
| SepSeptemberBest | 72°F(22°C) | 53°F(12°C) | 3.2 in(82 mm) | 77% | 4.1 |
| OctOctober | 60°F(15°C) | 43°F(6°C) | 3.6 in(91 mm) | 78% | 2.5 |
| NovNovember | 47°F(8°C) | 33°F(1°C) | 3.4 in(87 mm) | 83% | 1.5 |
| DecDecember | 35°F(2°C) | 24°F(-4°C) | 3.3 in(83 mm) | 89% | 1.1 |
1991–2020 averages. Sun is solar radiation in kWh/m² per day. Highlighted: the most comfortable months.
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