Photo: P199 · CC BY-SA 3.0Ice rarely forms: Rideau Lakes sees fewer frosts than 72% of Canadian towns
Expect July afternoons of about 26.1°C. Its yearly rain and snow top those of 69% of Canadian towns. The seasons are far apart: from a winter night to a summer afternoon the average spans 37°C. Plan time outside from May to September, when highs sit at 19–26°C.
These are not Rideau Lakes’s own readings: ECCC keeps no normals there, so the page uses Brockville, 33 km east.
A year in Rideau Lakes at a glance
Each month’s typical high and low, in °C.
What stands out about Rideau Lakes’s climate
Compared with Canadian towns, with its place among towns of 2,500+ in Ontario beside it.
What a year in Rideau Lakes feels like
Each season’s and each month’s usual high and low, 1991–2020.
Frost on 140 days, 20°C on 118
From October to April frost is routine, and in January it comes on almost every night. Some 8 nights a year drop under −20°C.
Frost days by month
Average days at 0°C or below
Days above 20°C by month
Average days
Rain and melted snow: about 1,017 mm a year
The most falls in July, the least in February. About 129 days a year bring 1 mm or more.
Rain and snow by month
Millimetres
Rain alone by month
Millimetres
About 180 cm of snow a year
Expect snow from October to April, with about 50 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 Rideau Lakes
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. A house here needs less heating than 70% of Canadian towns.
Living with Rideau Lakes’s climate
What the normals mean for a garden, a day outside and the depth of winter.
Gardens get from about 27 April to 14 October without frost, around 169 days in all.
Highs of 17–27°C with nights of 8°C or more come in May, Jun, Jul, Aug and Sep.
Parks & trails →Severe weather is a separate story from the averages: see Rideau Lakes’s hazards page.
Flood & hazards →ECCC’s normals location: Brockville
Behind the 1991–2020 normals for Brockville are 2 stations, which ECCC combines into one record.
| Distance from the town | 33 km east |
| Station altitude | 120 m |
| Completeness | meets the WMO “3 and 5” rule |
| WMO standard normals | Yes |
| Coldest reading, 1991–2020 | −31.5°C |
| Hottest reading, 1991–2020 | 35.0°C |
| Next-nearest location | Drummond Centre, 38 km |
How Rideau Lakes compares
Against the 2,611 Canadian towns and neighbourhoods of 2,500 or more, each read from its own normals location; the dots are the other locations those towns use in Ontario.
Nearby towns’ climate
Nearby places read from a different ECCC location (places on Rideau Lakes’s own would show the same figures). The nearest places to Rideau Lakes with figures are 24–30 km away.
| Town | July high | January low | Rain & snow |
|---|---|---|---|
| Rideau Lakes Brockville | 26.1°C | −11.3°C | 1,017 mm |
| Perth 24 km · Drummond Centre | 27.1°C 1.0°C warmer | −14.2°C 2.9°C colder | 939 mm |
| Merrickville 30 km · Kemptville | 26.8°C 0.7°C warmer | −14.0°C 2.7°C colder | 925 mm |
Rideau Lakes weather by month
Average daily high and low, mean temperature, rain and snow (as water) and snowfall by month, 1991–2020.
| Month | High | Low | Mean | Rain & snow | Snow |
|---|---|---|---|---|---|
| January | −3.1°C | −11.3°C | −7.2°C | 84 mm | 50 cm |
| February | −1.7°C | −10.3°C | −6.0°C | 64 mm | 41 cm |
| March | 3.7°C | −5.0°C | −0.7°C | 68 mm | 29 cm |
| April | 11.3°C | 1.8°C | 6.6°C | 89 mm | 8 cm |
| May | 18.8°C | 8.3°C | 13.5°C | 80 mm | under 1 cm |
| June | 23.4°C | 13.5°C | 18.5°C | 96 mm | 0 cm |
| July | 26.1°C | 16.5°C | 21.3°C | 99 mm | 0 cm |
| August | 25.4°C | 15.7°C | 20.6°C | 82 mm | 0 cm |
| September | 21.2°C | 11.7°C | 16.5°C | 96 mm | 0 cm |
| October | 13.8°C | 5.8°C | 9.7°C | 94 mm | 1 cm |
| November | 7.0°C | −0.2°C | 3.5°C | 81 mm | 11 cm |
| December | 0.4°C | −6.5°C | −3.0°C | 85 mm | 41 cm |
| Year | 12.2°C | 3.3°C | 7.8°C | 1,017 mm | 180 cm |
March has run from −26.0°C to 26.0°C in thirty years
Year to year, January varies most (a standard deviation of 3.1°C around −7.2°C) and June least (1.2°C).
Where Rideau Lakes’s numbers come from
Averages over 30 years, not a forecast.
- Normals: the Canadian Climate Normals, 1991–2020, at Brockville (the closest location with all twelve months of temperatures).
- Comparisons: Canadian towns and neighbourhoods of at least 2,500, each placed by its nearest location (city totals and reserves excluded).
- Not on this page: sunshine, which none of ECCC’s 450 locations publishes for 1991–2020, and the town’s own height above sea level, so no figure is adjusted for altitude.
Canadian Climate Normals 1991–2020 · ECCC Data Services End-use Licence. Data Source: Environment and Climate Change Canada
Questions about Rideau Lakes’s climate
How warm does Rideau Lakes get in summer?
Peak warmth comes in July, at about 26.1°C by mid-afternoon.
How cold does Rideau Lakes get in winter?
On a normal January night the air drops to −11.3°C, the coldest of the year.
How much rain and snow does Rideau Lakes get?
Some 1,017 mm falls in a year. Most of it comes in July (99 mm), the least in February (64 mm).
Are these figures for Rideau Lakes itself?
Not directly: Rideau Lakes has no ECCC normals of its own, and Brockville stands in for it.
Data Source: Environment and Climate Change Canada · ECCC Data Services End-use Licence Today’s forecast for Rideau Lakes →
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).