Sarnia weather in April

In April, Sarnia sees average daytime highs of 11°C and overnight lows near 3°C, with 85 mm of precipitation across 11.4 wet days and about 13.1 hours of daylight. It is the 7th-warmest and 2nd-wettest month of the year here.

Highs climb over the month, from about 8°C in the first days to 14°C by the end. The sky is clear or mostly clear about 22% of the time in April, and the air most often feels dry.

Daylight stretches from about 12 h 24 min at the start of April to 13 h 48 min by month's end. Set against the rest of the year, April is Sarnia's 7th-clearest and 5th-windiest month. For the whole year in context, see Sarnia's year-round climate.

Daytime high
11°
7th warmest
Overnight low
6th coldest
Precipitation
85 mm
11.4 wet days
Daylight
13 h 12 min
5:55 AM – 7:05 PM
Cloud cover
67%
7th clearest
Wind
15 km/h
5th windiest
Solar energy
4.95 kWh/m²
Travel score
2.7
out of 10

Sarnia is city in Ontario, Canada.

Air quality
Good
PM2.5 7 µg/m³ · 2019
Density
440/km²
people per km²
Founded
1830

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in April

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 8°C in the first days to 14°C by the end.

A typical April day in Sarnia reaches about 11°C in the afternoon and slips back to 3°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 4°C and 19°C. Set against its neighbours, April runs about 7°C warmer than March and about 7°C cooler than May.

10°20°151015202530
Avg high (°C)Avg low (°C)
181
281
381
491
591
692
792
8102
9102
10102
11103
12113
13113
14113
15113
16124
17124
18124
19124
20124
21135
22135
23135
24135
25135
26146
27146
28146
29146
30146

How April really feels in Sarnia

Once humidity and wind are folded in, April averages 0 days that feel above 32°C and 15 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
0
heat index over the day's high
Days feeling ≤ C
15
wind chill below the day's low

The story in April is cold — wind chill drags the overnight "feels like" below the raw low.

Sarnia weather by month

How April compares with the rest of the year at a glance. April is the 7th-warmest and 2nd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan-1° / -7°579.67.39.20.0
Feb / -7°518.46.310.20.0
Mar / -3°579.64.611.60.3
Apr11° / 8511.41.813.12.7
May18° / 10°8512014.45.4
Jun24° / 16°8710.8015.16.7
Jul26° / 18°7111014.86.6
Aug25° / 18°7010.4013.86.9
Sep21° / 14°739.1012.36.7
Oct15° / 7710.80.110.84.3
Nov / 669.72.49.51.2
Dec / -3°569.45.68.90.0

Cloud cover in April

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 22% of the time in April.

Beyond those clear spells, partly cloudy skies cover about 14% of April, with mostly cloudy or overcast conditions the remaining 65%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
13268
23268
33268
43367
53367
63367
73466
83466
93466
103466
113565
123565
133565
143565
153763
163763
173763
183763
193862
203763
213763
223763
233763
243763
253763
263664
273664
283664
293763
303763

Chance of precipitation in April

Any precipitationSnow

Sarnia gets around 85 mm of rain and snow over 11.4 wet days in April. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 38% and peaks near 39% on the wettest days, and about 2 days bring snow.

0%10%20%30%40%50%151015202530
Rain chance (%)Snow chance (%)
13610
23610
33710
43710
53710
63810
73810
83710
9379
10379
11378
12378
13377
14376
15376
16375
17375
18374
19374
20383
21383
22383
23382
24392
25392
26391
27391
28391
29391
30391

Humidity in April

DryComfortableHumidMuggyOppressiveMiserable

Most of April feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, April lands in the dry band about 98% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)
110000
210000
310000
410000
510000
610000
79910
89910
99910
109910
119910
129910
139820
149820
159820
169820
179820
189820
199820
209820
219820
229820
239730
249730
259730
269730
279730
289730
299730
309541

Wind in April

Winds average 15 km/h in April.

Across April, daily wind ranges from about 14 km/h on the calmest days to 15 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
115light breeze
215light breeze
315light breeze
415light breeze
515light breeze
615light breeze
715light breeze
815light breeze
915light breeze
1015light breeze
1115light breeze
1215light breeze
1315light breeze
1415light breeze
1515light breeze
1615light breeze
1715light breeze
1815light breeze
1915light breeze
2015light breeze
2115light breeze
2215light breeze
2315light breeze
2415light breeze
2515light breeze
2615light breeze
2715light breeze
2815light breeze
2914light breeze
3014light breeze

Sunrise & sunset in April

DaylightNight

Daylight runs from about 12 h 24 min at the start of April to 13 h 48 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 84 minutes over April. Sunrise moves from 6:21 AM to 5:32 AM, and sunset from 6:47 PM to 7:21 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.46:216:47
212.56:196:49
312.56:186:50
412.66:166:51
512.66:146:52
612.76:126:53
712.76:106:54
812.86:096:56
912.86:076:57
1012.96:056:58
1112.96:036:59
1213.06:027:00
1313.06:007:01
1413.15:587:03
1513.15:567:04
1613.25:557:05
1713.25:537:06
1813.35:517:07
1913.35:507:09
2013.45:487:10
2113.45:467:11
2213.55:457:12
2313.55:437:13
2413.55:427:14
2513.65:407:16
2613.65:387:17
2713.75:377:18
2813.75:357:19
2913.85:347:20
3013.85:327:21

Solar energy in April

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in April, about 4.95 kWh/m².

For context, solar energy here swings from a low near 1.36 kWh/m² to a high of 6.37 kWh/m² in June across the year — April's 4.95 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
14.4Bright
24.5Bright
34.5Bright
44.5Bright
54.5Bright
64.6Bright
74.6Bright
84.7Bright
94.7Bright
104.7Bright
114.8Bright
124.8Bright
134.8Bright
144.9Bright
154.9Bright
165.0Bright
175.0Bright
185.0Bright
195.1Bright
205.1Bright
215.2Bright
225.2Bright
235.2Bright
245.3Bright
255.3Bright
265.3Bright
275.4Bright
285.4Bright
295.4Bright
305.4Bright
Planning a trip in April

Is April a good time to visit Sarnia?

Our two travel scores rate April for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

2.7
Sightseeing
7th-best month of the year
0.0
Beach & pool
7th-best month of the year

April is a weaker month for outdoor sightseeing in Sarnia.

What to pack for Sarnia in April

From April's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In April, Sarnia sees daytime highs around 11°C and nights near 3°C. Pack a warm layer. Worth having: rain gear and sun protection. About 11 days see rain.

a warm layerrain gearsun protection

Sea temperature near Sarnia in April

The nearest coast averages about 3°C in April — 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.

0°10°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°C)Comfort
Jan2Bracing
Feb1Bracing
Mar1Bracing
Apr3Bracing
May7Bracing
Jun14Bracing
Jul20Refreshing
Aug22Refreshing
Sep20Cool
Oct14Bracing
Nov9Bracing
Dec5Bracing

UV index in Sarnia in April

LowModerateHighVery highExtreme

Clear-sky midday UV in April peaks 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.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJun 20UV 9Dec 20UV 1
UV index (midday)Level
Jan2Low
Feb2Moderate
Mar4Moderate
Apr5High
May7High
Jun9Very high
Jul8Very high
Aug7High
Sep6High
Oct3Moderate
Nov2Moderate
Dec1Low
Location & terrain

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.

3 km
19 m
16 km
69 m
80 km
216 m
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
April weather nearby: Port Huron 2.0 km · Mount Clemens 57 km · Clinton Township 61 km · Shelby 62 km · Strathroy 64 km · Chatham 65 km · Saint Clair Shores 67 km · Sterling Heights 68 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
Christian 53%none 35%Muslim 5%Hindu 2%

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. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).