Sarnia in Winter
In winter (December, January and February), Sarnia sees average daytime highs around 0°C and overnight lows near -6°C, with 164 mm of precipitation over about 27 wet days across the season. It is the coldest season of the year and the driest season of the year.
Over the season highs ease from about 4°C in early December to 1°C by late February. The sky is clear or mostly clear about 12% of the time across winter, and the air most often feels dry.
Winter is Sarnia's weakest season of the year to visit on our travel score. For the whole year in context, see Sarnia's year-round climate.
- Avg daytime high
- 0°C
- coldest season of the year
- Avg overnight low
- -6°C
- Precipitation
- 164 mm
- 27 wet days
- Avg wind
- 16 km/h
- Travel score
- 0.0
- weakest season of the year
- Months
- Dec · Jan · Feb
Temperature in Sarnia in Winter
Over the season highs ease from about 4°C in early December to 1°C by late February.
A typical winter day in Sarnia reaches about 0°C and drops to -6°C overnight. The warmest of the three months is December, the coolest January.
How winter really feels in Sarnia
Once humidity and wind are folded in, winter brings about 0 days that feel above 32°C and 90 that feel at or below 0°C.
The story in winter is cold — wind chill drags the overnight "feels like" below the raw low.
Sarnia weather by month
How the three winter months (December, January and February) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | -1° / -7° | 57 | 9.6 | 7.3 | 9.2 | 0.0 |
| Feb | 0° / -7° | 51 | 8.4 | 6.3 | 10.2 | 0.0 |
| Mar | 5° / -3° | 57 | 9.6 | 4.6 | 11.6 | 0.3 |
| Apr | 11° / 3° | 85 | 11.4 | 1.8 | 13.1 | 2.7 |
| May | 18° / 10° | 85 | 12 | 0 | 14.4 | 5.4 |
| Jun | 24° / 16° | 87 | 10.8 | 0 | 15.1 | 6.7 |
| Jul | 26° / 18° | 71 | 11 | 0 | 14.8 | 6.6 |
| Aug | 25° / 18° | 70 | 10.4 | 0 | 13.8 | 6.9 |
| Sep | 21° / 14° | 73 | 9.1 | 0 | 12.3 | 6.7 |
| Oct | 15° / 8° | 77 | 10.8 | 0.1 | 10.8 | 4.3 |
| Nov | 8° / 2° | 66 | 9.7 | 2.4 | 9.5 | 1.2 |
| Dec | 2° / -3° | 56 | 9.4 | 5.6 | 8.9 | 0.0 |
Cloud cover in Winter
The sky is clear or mostly clear about 12% of the time across winter.
Chance of precipitation in Winter
Sarnia gets around 164 mm of rain and snow over 27 wet days across winter. The line is the day-by-day chance of measurable precipitation.
Humidity in Winter
Most of winter feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Winter
Winds average 16 km/h across winter.
Sunrise & sunset in Winter
Daylight runs from about 9 h 06 min in early December to 10 h 54 min by late February. The lit band spans sunrise to sunset each day.
Solar energy in Winter
Average shortwave solar energy reaching the ground each day across winter, about 1.9 kWh/m².
Is winter a good time to visit Sarnia?
Our two travel scores rate winter for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
winter is a weaker month for outdoor sightseeing in Sarnia.
What to pack for Sarnia in Winter
From winter's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In winter, Sarnia sees daytime highs around 0°C and nights near -6°C. Pack a warm layer and a heavy coat. Worth having: rain gear. About 27 days see rain.
Sea temperature near Sarnia in Winter
The nearest coast averages about 3°C across winter — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 16 km away) is warmest in August at about 22°C and coldest in February near 1°C.
It's comfortable for a long swim from Jul 19 to Sep 8 — about 1.7 months when the water holds above 20°C.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 2 | 1 | 1 | 3 | 7 | 14 | 20 | 22 | 20 | 14 | 9 | 5 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Refreshing | Refreshing | Cool | Bracing | Bracing | Bracing |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 2 | Bracing |
| Feb | 1 | Bracing |
| Mar | 1 | Bracing |
| Apr | 3 | Bracing |
| May | 7 | Bracing |
| Jun | 14 | Bracing |
| Jul | 20 | Refreshing |
| Aug | 22 | Refreshing |
| Sep | 20 | Cool |
| Oct | 14 | Bracing |
| Nov | 9 | Bracing |
| Dec | 5 | Bracing |
UV index in Sarnia in Winter
Clear-sky midday UV across winter averages around 2. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Sarnia peaks around June 20 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 20 at about 1 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 2 | 2 | 4 | 5 | 7 | 9 | 8 | 7 | 6 | 3 | 2 | 1 |
| Level | Low | Moderate | Moderate | High | High | Very high | Very high | High | High | Moderate | Moderate | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 2 | Low |
| Feb | 2 | Moderate |
| Mar | 4 | Moderate |
| Apr | 5 | High |
| May | 7 | High |
| Jun | 9 | Very high |
| Jul | 8 | Very high |
| Aug | 7 | High |
| Sep | 6 | High |
| Oct | 3 | Moderate |
| Nov | 2 | Moderate |
| Dec | 1 | Low |
Where is Sarnia?
Sarnia sits at 43.0°N, 82.4°W, 185 m above sea level, in Canada. The nearest listed city is Port Huron, 2.0 km away.
Topography around Sarnia
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Sarnia.
Within 3 km, the terrain around Sarnia has only modest variations in elevation — a maximum elevation change of 19 m around an average of 182 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 69 m; within 80 km, only modest variations in elevation — a maximum elevation change of 216 m.
The land around Sarnia is covered by artificial surfaces (52%) and trees (22%) within 3 km, cropland (27%), trees (25%) and water (24%) within 16 km, and cropland (45%) and water (25%) within 80 km.
Canada travel facts
- Travel advisory
- Level 1
- Exercise Normal Precautions
- Power plugs
- Type A / B
- 120 V · 60 Hz
- Prices
- ≈ 83% of US
- price level, 2025
- GDP per capita
- $55,698
- 2025
- Happiness
- 6.7 / 10
- World Happiness, 2025
- Safe drinking water
- 97%
- of population, 2024
- Homicide rate
- 2
- per 100k, 2023
- Road deaths
- 5.3
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Sarnia (42.9787°, -82.4041°, elevation 185 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.