Cornwall Climate by Month
Cornwall, 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 Cornwall's climate in short. July is the warmest month, with highs around 81°F (27°C); January is the coolest at 25°F (-4°C), and nights dip to 8°F (-13°C). About 40 in (1015 mm) of rain falls in a typical year, with no clear rainy season.
- Warmest month
- 81°F(27°C)
- Average high, July
- Coldest nights
- 8°F(-13°C)
- Average low, January
- Rain per year
- 40 in(1015 mm)
- No clear rainy season
- Humidity
- 77%
- Sunniest: June
Best and worst months in Cornwall
Best for weatherJune, August and September are the best time for weather in Cornwall: highs near 76°F (24°C) and about 3.6 in (91 mm) of rain a month.
Least pleasantJanuary is the least pleasant month: it's the coldest, with highs of only 25°F (-4°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)
Cornwall weather by month
| Month | High | Low | Rain | Humidity | Sun |
|---|---|---|---|---|---|
| JanJanuary | 25°F(-4°C) | 8°F(-13°C) | 3.0 in(77 mm) | 94% | 1.5 |
| FebFebruary | 27°F(-3°C) | 9°F(-13°C) | 2.4 in(62 mm) | 88% | 2.3 |
| MarMarch | 37°F(3°C) | 20°F(-7°C) | 2.5 in(63 mm) | 75% | 3.4 |
| AprApril | 52°F(11°C) | 33°F(1°C) | 3.5 in(90 mm) | 64% | 4.5 |
| MayMay | 67°F(19°C) | 46°F(8°C) | 3.7 in(95 mm) | 65% | 5.3 |
| JunJuneBest | 76°F(24°C) | 55°F(13°C) | 4.0 in(102 mm) | 70% | 5.7 |
| JulJuly | 81°F(27°C) | 60°F(16°C) | 3.8 in(96 mm) | 71% | 5.7 |
| AugAugustBest | 79°F(26°C) | 59°F(15°C) | 3.4 in(86 mm) | 70% | 5.0 |
| SepSeptemberBest | 72°F(22°C) | 51°F(11°C) | 3.3 in(84 mm) | 75% | 4.0 |
| OctOctober | 58°F(14°C) | 40°F(5°C) | 4.1 in(103 mm) | 76% | 2.3 |
| NovNovember | 45°F(7°C) | 30°F(-1°C) | 3.2 in(82 mm) | 80% | 1.4 |
| DecDecember | 31°F(0°C) | 17°F(-8°C) | 3.0 in(75 mm) | 90% | 1.1 |
1991–2020 averages. Sun is solar radiation in kWh/m² per day. Highlighted: the most comfortable months.
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