Ajax climate
Ajax (Ontario, Canada) has a hot-summer humid continental climate (Köppen Dfa). The average temperature over the year is 9 °C48 °F, and about 719 mm28 in of precipitation falls in an average year.
Temperature by month
Precipitation by month
Ajax 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 | 846 | 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 | 846 | 133 | 439 | 612.4 | 14 |
| Dec | 134 | −524 | −229 | 622.4 | 28 |
| Year | 2882 | −916 | 948 | 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% | 81% | 1.4 | 9:15 |
| Feb | 89% | 78% | 2.1 | 10:25 |
| Mar | 82% | 74% | 3.4 | 11:48 |
| Apr | 79% | 75% | 4.5 | 13:23 |
| May | 76% | 74% | 5.5 | 14:43 |
| Jun | 72% | 68% | 6.1 | 15:27 |
| Jul | 67% | 64% | 6.0 | 15:09 |
| Aug | 68% | 62% | 5.3 | 13:59 |
| Sep | 71% | 60% | 4.2 | 12:26 |
| Oct | 78% | 74% | 2.5 | 10:55 |
| Nov | 83% | 75% | 1.6 | 9:35 |
| Dec | 88% | 81% | 1.2 | 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 Ajax 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, 60%) 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 15.4 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 December, about 17 cm).
Best time to visit Ajax
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 Ajax
- Winter (December–February) — highs −229 to 1 °C34 °F, lows −916 to −5 °C24 °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 8 °C46 °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 846 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 Ajax compares
Compared with Oshawa, about 16 km to the east, Ajax has practically the same average temperature and receives a similar amount of precipitation.
Of the 40 places in Canada covered by World Climates, Ajax is the 15th warmest by annual mean temperature and the 28th 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), Buffalo (United States, Dfa) and Lansing (United States, Dfa).
Nearby places
- Oshawa 16 km · 9 °C47 °F · 719 mm28 in
- Markham 19 km · 8 °C47 °F · 723 mm28 in
- Toronto 33 km · 9 °C48 °F · 774 mm30 in
- Brampton 62 km · 8 °C47 °F · 770 mm30 in
- St. Catharines 77 km · 10 °C50 °F · 872 mm34 in
- Barrie 79 km · 7 °C45 °F · 623 mm25 in
- Guelph 104 km · 8 °C46 °F · 770 mm30 in
- Buffalo 108 km · 9 °C49 °F · 947 mm37 in
Frequently asked questions
What is the warmest month in Ajax?
July is the warmest month in Ajax, with an average high of 28 °C (82 °F) and an average low of 18 °C (64 °F).
What is the coldest month in Ajax?
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 Ajax?
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 Ajax?
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 Ajax lies at about 97 m. Temperatures on this page were therefore adjusted by +0.7 °C1.3 °F using the standard lapse rate of 6.5 °C per 1,000 m.