Afternoon heat in Saint-Louis beats that of 78% of Canadian towns
January nights here settle around −13.5°C. It is a wet place: more rain and snow fall here than on 74% of Canadian towns. Some 40°C separates winter nights from summer afternoons. The heating season runs October to April: each of those months averages under 10°C.
Figures: ECCC’s 1991–2020 normals for Montréal Trudeau (Airport) (15 km west).
A year in Saint-Louis at a glance
Each month’s typical high and low, in °C.
What stands out about Saint-Louis’s climate
Compared with Canadian towns, with its place among towns of 2,500+ in Quebec beside it.
What a year in Saint-Louis feels like
Seasons and months as ECCC’s 1991–2020 normals give them: a typical day’s high and low.
Frost on 146 days, 20°C on 121
Frost comes from October to April; in January almost every night freezes. Deep cold, under −20°C, comes on about 12 nights a year.
Frost days by month
Average days at 0°C or below
Days above 20°C by month
Average days
1,041 mm of precipitation in a typical year
October is the wettest month and February the driest. On about 122 days a year, 1 mm or more falls.
Rain and snow by month
Millimetres
Rain alone by month
Millimetres
217 cm of snow in a typical year
Snow falls from October to April, most of all in January (about 52 cm).
Snowfall by month
Centimetres
Snow on the ground by month
Centimetres at month’s end
Heating a home in Saint-Louis
93% of a year’s heating need falls between October and April. Months averaging under 10°C: October to April.
The count adds up, day by day, how far the mean temperature falls short of 18°C. A house here needs less heating than 62% of Canadian towns.
Living with Saint-Louis’s climate
The averages read for the garden, the outdoors and the coldest and hottest days.
The frost-free stretch runs from about 29 April to about 14 October, some 167 days in a normal year.
Highs of 17–27°C with nights of 8°C or more come in May, Jun, Jul, Aug and Sep.
Parks & trails →The wind chill passes −20 on about 40 days in a normal year.
About 50 days a year feel above 30 on the humidex.
Thirty-year normals hide the storms and the extremes: the hazards page has Saint-Louis’s risks.
Flood & hazards →ECCC’s normals location: Montréal Trudeau (Airport)
Montréal Trudeau (Airport) is a composite: ECCC joins 3 stations’ readings to make its 1991–2020 normals.
| Distance from the town | 15 km west |
| Station altitude | 36 m |
| Completeness | meets the WMO “3 and 5” rule |
| WMO standard normals | No |
| Coldest reading, 1991–2020 | −31.8°C |
| Hottest reading, 1991–2020 | 36.6°C |
| Average wind | 15.4 km/h on average, most often from the west |
| Next-nearest location | L'Acadie, 31 km |
How Saint-Louis 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 Quebec.
Nearby towns’ climate
Places around Saint-Louis whose figures come from another normals location. Saint-Louis has few close neighbours with figures, so the list reaches 11–16 km out.
| Town | July high | January low | Rain & snow |
|---|---|---|---|
| Saint-Louis Montréal Trudeau (Airport) | 26.7°C | −13.5°C | 1,041 mm |
| Brossard 11 km · L'Acadie | 26.6°C about the same | −13.6°C about the same | 1,041 mm |
| Montréal-Est 14 km · L'Assomption | 26.6°C about the same | −16.0°C 2.5°C colder | 1,041 mm |
Saint-Louis 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 | −5.0°C | −13.5°C | −9.2°C | 86 mm | 52 cm |
| February | −3.4°C | −12.4°C | −8.0°C | 66 mm | 47 cm |
| March | 2.4°C | −6.5°C | −2.0°C | 77 mm | 37 cm |
| April | 11.3°C | 1.1°C | 6.2°C | 90 mm | 15 cm |
| May | 19.4°C | 8.3°C | 13.9°C | 86 mm | 0 cm |
| June | 24.2°C | 13.8°C | 19.0°C | 84 mm | 0 cm |
| July | 26.7°C | 16.7°C | 21.7°C | 91 mm | 0 cm |
| August | 25.7°C | 15.6°C | 20.6°C | 94 mm | 0 cm |
| September | 21.1°C | 10.9°C | 16.0°C | 89 mm | 0 cm |
| October | 13.2°C | 4.5°C | 8.9°C | 103 mm | 1 cm |
| November | 6.1°C | −1.7°C | 2.3°C | 84 mm | 16 cm |
| December | −1.2°C | −8.7°C | −5.0°C | 92 mm | 48 cm |
| Year | 11.7°C | 2.3°C | 7.0°C | 1,041 mm | 217 cm |
From −26.9°C to 25.8°C: March’s coldest and warmest days since 1991
From one year to the next, January’s average typically shifts by 3.0°C around its normal of −9.2°C, the widest of any month, while June’s shifts by 1.1°C.
Where Saint-Louis’s numbers come from
Averages over 30 years, not a forecast.
- Normals: the 1991–2020 Canadian Climate Normals at Montréal Trudeau (Airport), the closest ECCC location with twelve months of temperature normals.
- 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 (no 1991–2020 normals exist for it) and any altitude adjustment, since there is no elevation for the town itself.
Canadian Climate Normals 1991–2020 · ECCC Data Services End-use Licence. Data Source: Environment and Climate Change Canada
Questions about Saint-Louis’s climate
How warm does Saint-Louis get in summer?
Highs reach 26.7°C on an average July day; no month is warmer.
How cold does Saint-Louis get in winter?
At its coldest, in January, the normal low is −13.5°C.
How much rain and snow does Saint-Louis get?
Rain and snow add up to about 1,041 mm of water a year; October brings the most (103 mm), February the least (66 mm).
How long does snow stay on the ground?
Count on about 101 days of snow cover a year, 1 cm or deeper.
Are these figures for Saint-Louis itself?
They are the normals for Montréal Trudeau (Airport), measured just outside Saint-Louis itself.
Data Source: Environment and Climate Change Canada · ECCC Data Services End-use Licence Today’s forecast for Saint-Louis →
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).