Photo: Roncanada · CC BY 4.0Saint-Thomas is wetter than 82% of Canadian towns: 1,109 mm of rain and snow a year
January mornings start at about −16.0°C. Temperatures cover 43°C across the year, low to high. Winter nights are cold: in January they are colder than in 75% of Canadian towns. Heating does most of its work from October to April, in months below 10°C on average.
No ECCC station in Saint-Thomas has 1991–2020 normals; the page reads L'Assomption, 24 km south, instead.
A year in Saint-Thomas at a glance
Each month’s typical high and low, in °C.
What stands out about Saint-Thomas’s climate
Compared with Canadian towns, with its place among towns of 2,500+ in Quebec beside it.
What a year in Saint-Thomas feels like
Typical highs and lows by season and by month, from ECCC’s 1991–2020 normals.
Frost on 161 days, 20°C on 119
From October to May frost is routine, and in January it comes on almost every night. On about 24 nights a year the air falls below −20°C.
Frost days by month
Average days at 0°C or below
Days above 20°C by month
Average days
1,109 mm of precipitation in a typical year
The most falls in August, the least in February. About 145 days a year bring 1 mm or more.
Rain and snow by month
Millimetres
Rain alone by month
Millimetres
ECCC’s L'Assomption normals leave out precipitation and snow; both come from Fleury here, 36 km away.
About 202 cm of snow a year
From October to April snow is likely; December is the peak, at about 49 cm.
Snowfall by month
Centimetres
Heating a home in Saint-Thomas
93% of a year’s heating need falls between October and April. Months averaging under 10°C: October to April.
Degree days add up how far each day’s mean temperature falls below 18°C over a year.
Living with Saint-Thomas’s climate
What the normals mean for a garden, a day outside and the depth of winter.
Afternoons of 17–27°C and nights of at least 8°C arrive in Jun, Jul, Aug and Sep.
Parks & trails →Count on some 44 days a year when the wind makes it feel below −20.
About 49 days a year turn sultry, with the humidex past 30.
Thirty-year normals hide the storms and the extremes: the hazards page has Saint-Thomas’s risks.
Flood & hazards →ECCC’s normals location: L'Assomption
The page’s figures are ECCC’s 1991–2020 normals for L'Assomption, one of its 450 normals locations.
| Distance from the town | 24 km south |
| Station altitude | 21 m |
| Completeness | meets the WMO “3 and 5” rule |
| WMO standard normals | No |
| Precipitation from | Fleury, 36 km |
| Coldest reading, 1991–2020 | −40.0°C |
| Hottest reading, 1991–2020 | 36.2°C |
| Average wind | 10.0 km/h on average, most often from the south-west |
| Next-nearest location | Fleury, 36 km |
How Saint-Thomas 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 Quebec.
Nearby towns’ climate
Places around Saint-Thomas whose figures come from another normals location. Saint-Thomas has no close neighbour with figures; the nearest is 15 km away.
| Town | July high | January low | Rain & snow |
|---|---|---|---|
| Saint-Thomas L'Assomption | 26.6°C | −16.0°C | 1,109 mm |
| Berthierville 15 km · Fleury | 26.0°C 0.6°C cooler | −14.8°C 1.2°C milder | 1,109 mm |
Saint-Thomas 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 | −5.9°C | −16.0°C | −10.9°C | 81 mm | 45 cm |
| February | −4.0°C | −14.8°C | −9.4°C | 61 mm | 43 cm |
| March | 1.8°C | −8.3°C | −3.2°C | 71 mm | 38 cm |
| April | 10.8°C | 0.1°C | 5.5°C | 96 mm | 13 cm |
| May | 19.2°C | 7.2°C | 13.2°C | 98 mm | under 1 cm |
| June | 24.3°C | 12.4°C | 18.4°C | 102 mm | 0 cm |
| July | 26.6°C | 14.8°C | 20.7°C | 106 mm | 0 cm |
| August | 25.5°C | 13.7°C | 19.6°C | 114 mm | 0 cm |
| September | 21.1°C | 9.2°C | 15.2°C | 97 mm | 0 cm |
| October | 13.0°C | 3.2°C | 8.1°C | 108 mm | 2 cm |
| November | 5.4°C | −2.7°C | 1.3°C | 90 mm | 12 cm |
| December | −1.9°C | −10.2°C | −6.1°C | 85 mm | 49 cm |
| Year | 11.3°C | 0.7°C | 6.0°C | 1,109 mm | 202 cm |
January varies most from one year to the next (3.1°C), June least
Each bar spans a month’s coldest and warmest readings over thirty years; March’s run from −29.5°C in 1992 to 26.0°C in 2012.
Where Saint-Thomas’s numbers come from
Averages over 30 years, not a forecast.
- Normals: the 1991–2020 normals from ECCC for L'Assomption, its nearest location with complete temperatures.
- Other locations: precipitation and snowfall come from the nearest location that publishes all twelve months of them, as named above.
- Comparisons: Canada’s towns and neighbourhoods of 2,500+ (no city totals, no reserves), each through its own nearest location.
- Not on this page: a sunshine figure (ECCC published none for 1991–2020) and any lapse-rate correction for height, as the town has no elevation here.
Canadian Climate Normals 1991–2020 · ECCC Data Services End-use Licence. Data Source: Environment and Climate Change Canada
Questions about Saint-Thomas’s climate
How warm does Saint-Thomas get in summer?
Of all twelve months, July has the warmest afternoons, about 26.6°C.
How cold does Saint-Thomas get in winter?
Expect nights around −16.0°C in January; no month is colder.
How much rain and snow does Saint-Thomas get?
Around 1,109 mm a year in all, from 114 mm in August down to 61 mm in February.
Are these figures for Saint-Thomas itself?
No, they come from L'Assomption; ECCC keeps no 1991–2020 normals in Saint-Thomas itself.
Data Source: Environment and Climate Change Canada · ECCC Data Services End-use Licence Today’s forecast for Saint-Thomas →
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).