Photo: Harleyd613 · CC BY 4.0Ottawa has warmer summer afternoons than 78% of Canadian towns
Nights in January average −14.0°C. It is a wet place: more rain and snow fall here than on 60% of Canadian towns. Temperatures cover 41°C across the year, low to high. Plan for rain or snow on about 120 days a year, the days with 1 mm or more.
1991–2020 normals from ECCC’s Ottawa (City) station, 2.3 km north-west.
A year in Ottawa at a glance
Each month’s typical high and low, in °C.
What stands out about Ottawa’s climate
Compared with Canadian towns, with its place among towns of 2,500+ in Ontario beside it.
What a year in Ottawa feels like
Seasons and months as ECCC’s 1991–2020 normals give them: a typical day’s high and low.
About 147 frosts and 121 warm days a year
From October to April frost is routine, and in January it comes on almost every night. Deep cold, under −20°C, comes on about 15 nights a year.
Frost days by month
Average days at 0°C or below
Days above 20°C by month
Average days
938 mm of precipitation in a typical year
June brings the most rain and snow; February, the least.
Rain and snow by month
Millimetres
Rain alone by month
Millimetres
185 cm of snow in a typical year
Expect snow from October to April, with about 45 cm in January, the snowiest month.
Snowfall by month
Centimetres
Snow on the ground by month
Centimetres at month’s end
Heating a home in Ottawa
93% of a year’s heating need falls between October and April. Months averaging under 10°C: October to April.
A heating degree day is one degree of shortfall below 18°C for one day, summed over the year.
Living with Ottawa’s climate
The averages read for the garden, the outdoors and the coldest and hottest days.
Tender plants are usually safe from around 30 April until frost returns near 6 October: about 158 days.
Warm afternoons without cold nights, 17–27°C and 8°C or more, mark May, Jun, Jul, Aug and Sep.
Parks & trails →On some 39 days a year the wind chill drops past −20; mitts and a scarf earn their place.
Expect around 50 sticky days a year with the humidex above 30.
Severe weather is a separate story from the averages: see Ottawa’s hazards page.
Flood & hazards →ECCC’s normals location: Ottawa (City)
Ottawa (City) is a composite: ECCC joins 2 stations’ readings to make its 1991–2020 normals.
| Distance from the town | 2.3 km north-west |
| Station altitude | 79 m |
| Completeness | meets the WMO “3 and 5” rule |
| WMO standard normals | Yes |
| Coldest reading, 1991–2020 | −32.2°C |
| Hottest reading, 1991–2020 | 37.3°C |
| Average wind | 11.5 km/h on average, most often from the west |
| Next-nearest location | Ottawa (Airport), 5.5 km |
How Ottawa compares
Placed among 2,611 Canadian towns and neighbourhoods of 2,500+, each on its nearest normals location; each dot is another location used in Ontario.
Nearby towns’ climate
Nearby places read from a different ECCC location (places on Ottawa’s own would show the same figures). Ottawa has few close neighbours with figures, so the list reaches 22–29 km out.
Ottawa weather by month
Each month’s normals, 1991–2020: high, low, mean, precipitation and snowfall.
| Month | High | Low | Mean | Rain & snow | Snow |
|---|---|---|---|---|---|
| January | −5.2°C | −14.0°C | −9.6°C | 65 mm | 45 cm |
| February | −3.3°C | −12.9°C | −8.1°C | 52 mm | 41 cm |
| March | 2.5°C | −6.9°C | −2.2°C | 62 mm | 31 cm |
| April | 11.2°C | 1.1°C | 6.2°C | 81 mm | 8 cm |
| May | 19.4°C | 8.0°C | 13.8°C | 80 mm | 0 cm |
| June | 24.2°C | 13.3°C | 18.8°C | 95 mm | 0 cm |
| July | 26.7°C | 15.8°C | 21.3°C | 92 mm | 0 cm |
| August | 25.6°C | 14.6°C | 20.1°C | 87 mm | 0 cm |
| September | 21.1°C | 10.1°C | 15.6°C | 87 mm | 0 cm |
| October | 13.3°C | 4.1°C | 8.8°C | 90 mm | 2 cm |
| November | 5.8°C | −1.8°C | 2.0°C | 72 mm | 16 cm |
| December | −1.5°C | −8.7°C | −5.1°C | 74 mm | 43 cm |
| Year | 11.7°C | 1.9°C | 6.8°C | 938 mm | 185 cm |
A January here can run warm or cold, its average moving by about 3.1°C; the steadiest month is June
Records from 1991 to 2020: no month spans more than March, between −28.5°C (2003) and 26.5°C (2012).
Where Ottawa’s numbers come from
Averages over 30 years, not a forecast.
- Normals: the Canadian Climate Normals, 1991–2020, at Ottawa (City) (the closest location with all twelve months of temperatures).
- Comparisons: Canada’s towns and neighbourhoods of 2,500+ (no city totals, no reserves), each through its own nearest location.
- Not on this page: sunshine, not in ECCC’s 1991–2020 normals, and the effect of the town’s height, for which there is no figure.
Canadian Climate Normals 1991–2020 · ECCC Data Services End-use Licence. Data Source: Environment and Climate Change Canada
Questions about Ottawa’s climate
How warm does Ottawa get in summer?
Midsummer means July, with afternoons near 26.7°C on a typical day.
How cold does Ottawa get in winter?
Lows sink to −14.0°C on an average January night.
How much rain and snow does Ottawa get?
Some 938 mm falls in a year. Most of it comes in June (95 mm), the least in February (52 mm).
How long does snow stay on the ground?
In a normal winter there are about 115 days with at least 1 cm of snow lying.
Are these figures for Ottawa itself?
Yes: they are ECCC’s 1991–2020 normals for Ottawa (City), a location inside Ottawa.
Data Source: Environment and Climate Change Canada · ECCC Data Services End-use Licence Today’s forecast for Ottawa →
Adapted from Statistics Canada (Census of Population 2021, population estimates 2025, 2021 census boundaries) under the Statistics Canada Open Licence; this does not constitute an endorsement by Statistics Canada. Neighbourhood names in some cities © OpenStreetMap contributors (ODbL).