Sarnia in Spring
In spring (March, April and May), Sarnia sees average daytime highs around 11°C and overnight lows near 3°C, with 226 mm of precipitation over about 33 wet days across the season. It is the 3rd-warmest season and the 2nd-wettest season.
Over the season highs climb from about 2°C in early March to 21°C by late May. The sky is clear or mostly clear about 23% of the time across spring, and the air most often feels dry.
Spring is Sarnia's 3rd-best season to visit on our travel score. For the whole year in context, see Sarnia's year-round climate.
- Avg daytime high
- 11°C
- 3rd-warmest season
- Avg overnight low
- 3°C
- Precipitation
- 226 mm
- 33 wet days
- Avg wind
- 14 km/h
- Travel score
- 2.8
- 3rd-best season
- Months
- Mar · Apr · May
Temperature in Sarnia in Spring
Over the season highs climb from about 2°C in early March to 21°C by late May.
A typical spring day in Sarnia reaches about 11°C and drops to 3°C overnight. The warmest of the three months is May, the coolest March.
How spring really feels in Sarnia
Once humidity and wind are folded in, spring brings about 0 days that feel above 32°C and 46 that feel at or below 0°C.
The story in spring is cold — wind chill drags the overnight "feels like" below the raw low.
Sarnia weather by month
How the three spring months (March, April and May) 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 Spring
The sky is clear or mostly clear about 23% of the time across spring.
Chance of precipitation in Spring
Sarnia gets around 226 mm of rain and snow over 33 wet days across spring. The line is the day-by-day chance of measurable precipitation.
Humidity in Spring
Most of spring feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Spring
Winds average 14 km/h across spring.
Sunrise & sunset in Spring
Daylight runs from about 10 h 54 min in early March to 14 h 54 min by late May. The lit band spans sunrise to sunset each day.
Solar energy in Spring
Average shortwave solar energy reaching the ground each day across spring, about 4.9 kWh/m².
Is spring a good time to visit Sarnia?
Our two travel scores rate spring for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
spring is a weaker month for outdoor sightseeing in Sarnia.
What to pack for Sarnia in Spring
From spring's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In spring, Sarnia sees daytime highs around 11°C and nights near 3°C. Pack a warm layer and a heavy coat. Worth having: rain gear and sun protection. About 33 days see rain.
Sea temperature near Sarnia in Spring
The nearest coast averages about 4°C across spring — 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 Spring
Clear-sky midday UV across spring averages around 5 — enough to warrant sun protection. 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.