Oshawa climate
Oshawa (Ontario, Canada) has a hot-summer humid continental climate (Köppen Dfa). The average temperature over the year is 9 °C47 °F, and about 719 mm28 in of precipitation falls in an average year.
Temperature by month
Precipitation by month
Oshawa climate table
| Month | High °C°F | Low °C°F | Mean °C°F | Precip. mmin | Frost days |
|---|---|---|---|---|---|
| Jan | −229 | −916 | −523 | 522.0 | 30 |
| Feb | −130 | −916 | −523 | 471.9 | 28 |
| Mar | 439 | −424 | 032 | 512.0 | 27 |
| Apr | 1151 | 134 | 643 | 682.7 | 14 |
| May | 1864 | 745 | 1355 | 662.6 | 1 |
| Jun | 2475 | 1457 | 1966 | 652.6 | 0 |
| Jul | 2882 | 1864 | 2373 | 672.6 | 0 |
| Aug | 2781 | 1763 | 2272 | 542.1 | 0 |
| Sep | 2373 | 1356 | 1865 | 592.3 | 0 |
| Oct | 1558 | 744 | 1151 | 672.6 | 2 |
| Nov | 745 | 133 | 439 | 612.4 | 14 |
| Dec | 134 | −523 | −229 | 622.4 | 28 |
| Year | 2882 | −916 | 947 | 71928 | 143 |
“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 | 90% | 83% | 1.3 | 9:15 |
| Feb | 89% | 79% | 2.1 | 10:25 |
| Mar | 82% | 76% | 3.3 | 11:48 |
| Apr | 79% | 80% | 4.4 | 13:23 |
| May | 76% | 83% | 5.4 | 14:43 |
| Jun | 72% | 80% | 5.9 | 15:27 |
| Jul | 67% | 75% | 5.9 | 15:09 |
| Aug | 68% | 71% | 5.2 | 13:59 |
| Sep | 71% | 66% | 4.1 | 12:26 |
| Oct | 78% | 74% | 2.5 | 10:55 |
| Nov | 83% | 75% | 1.6 | 9:34 |
| Dec | 88% | 82% | 1.1 | 8:55 |
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 Oshawa is like
The warmest month is July, with an average high of 28 °C82 °F and a low of 18 °C64 °F. The coldest is January, when highs average −2 °C29 °F and lows −9 °C16 °F. Seasons are strongly marked: the warmest month is on average 27.9 °C50.3 °F warmer than the coldest.
Annual precipitation is moderate at about 719 mm28 in. Rain is spread fairly evenly through the year. The wettest month is April (68 mm2.7 in), the driest is February (47 mm1.9 in).
Relative humidity ranges from 67% in July to 90% in January. The clearest skies (lowest average cloud amount, 66%) are typical of September. Average wind speed near the ground ranges from 10 km/h (6 mph) in July to 16 km/h (10 mph) in February. Daylight lasts from about 8.9 hours in December to 15.5 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 December, about 17 cm).
Best time to visit Oshawa
Based on these averages, the most comfortable months for sightseeing and outdoor activities are June–September: average highs of 23 °C73 °F to 28 °C82 °F with 54 mm2.1 in to 67 mm2.6 in of precipitation per month.
The most challenging month is January, which is cold, with average highs of −2 °C29 °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 Oshawa
- Winter (December–February) — highs −229 to 1 °C34 °F, lows −916 to −5 °C23 °F, about 54 mm2.1 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 439 to 18 °C64 °F, lows −424 to 7 °C45 °F, about 62 mm2.4 in of precipitation a month. Pack a warm coat, layers and closed shoes.
- Summer (June–August) — highs 2475 to 28 °C82 °F, lows 1457 to 18 °C64 °F, about 62 mm2.4 in of precipitation a month. Pack light summer clothes such as T-shirts, shorts or light dresses and an extra layer for the cooler mornings and evenings.
- Autumn (September–November) — highs 745 to 23 °C73 °F, lows 133 to 13 °C56 °F, about 62 mm2.5 in of precipitation a month. Pack long sleeves, a sweater and a medium jacket.
How Oshawa compares
Compared with Markham, about 34 km to the west, Oshawa is on average 0.4 °C0.7 °F warmer and receives a similar amount of precipitation. The difference is largest in February (0.7 °C1.2 °F warmer).
Of the 40 places in Canada covered by World Climates, Oshawa is the 17th warmest by annual mean temperature and the 27th 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: Ann Arbor (United States, Dfa), Lansing (United States, Dfa) and Buffalo (United States, Dfa).
The same NASA POWER grid cell also contains Whitby (pop. 138,501). Their long-term averages in this dataset are essentially the same as for Oshawa, so they do not have separate pages.
Nearby places
- Ajax 16 km · 9 °C48 °F · 719 mm28 in
- Markham 34 km · 8 °C47 °F · 723 mm28 in
- Toronto 49 km · 9 °C48 °F · 774 mm30 in
- Brampton 77 km · 8 °C47 °F · 770 mm30 in
- Barrie 86 km · 7 °C45 °F · 623 mm25 in
- St. Catharines 87 km · 10 °C50 °F · 872 mm34 in
- Buffalo 113 km · 9 °C49 °F · 947 mm37 in
- Guelph 120 km · 8 °C46 °F · 770 mm30 in
Frequently asked questions
What is the warmest month in Oshawa?
July is the warmest month in Oshawa, with an average high of 28 °C (82 °F) and an average low of 18 °C (64 °F).
What is the coldest month in Oshawa?
January is the coldest month, with an average high of -2 °C (29 °F) and an average low of -9 °C (16 °F).
When does it rain the most in Oshawa?
April is the wettest month with about 68 mm (2.7 in) of precipitation; February is the driest with about 47 mm (1.9 in).
What is the best time to visit Oshawa?
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 205 m, while Oshawa lies at about 105 m. Temperatures on this page were therefore adjusted by +0.7 °C1.2 °F using the standard lapse rate of 6.5 °C per 1,000 m.