nomadseason

Monthly climate in Sarnia, Ontario, Canada

Last updated: May 6, 2024

Under the Köppen–Geiger climate classification Sarnia features a humid continental climate (Dfb).Temperatures typically range between -3 °C (27 °F) and 23 °C (73 °F) through the year, but rarely can drop to -24 °C (-11 °F) or can rise to as high as 34 °C (93 °F).The average annual precipitation amounts to about 925 mm (36.4 inches) and receives 132 rainy days on the 1 mm (0.04 inches) threshold annually.Sarnia enjoys an average of 2845 hours of sunshine throughout the year, and daylight varies from 9 hours 3 minutes to 15 hours 17 minutes per day.

Monthly average temperatures in Sarnia, Ontario, Canada §

The warmest months in Sarnia are June, July and August, with daily mean temperatures ranging from 20 to 23 °C (68 - 73 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from -3 to 0 °C (27 - 33 °F) throughout the day. On average each year, Sarnia experiences 53 days above 25 °C (77.0 °F) and 101 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Sarnia, Ontario, Canada.Generated using Copernicus Climate Change Service information.Data for period from January 2017 to June 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Maximum 10°C
(51°F)		 15°C
(59°F)		 19°C
(67°F)		 25°C
(77°F)		 29°C
(85°F)		 31°C
(89°F)		 34°C
(93°F)		 31°C
(89°F)		 33°C
(91°F)		 27°C
(81°F)		 21°C
(71°F)		 16°C
(61°F)
Mean maximum 8°C
(46°F)		 11°C
(52°F)		 16°C
(62°F)		 21°C
(71°F)		 28°C
(84°F)		 30°C
(87°F)		 32°C
(89°F)		 30°C
(87°F)		 30°C
(86°F)		 25°C
(78°F)		 16°C
(61°F)		 12°C
(54°F)
Average high -0°C
(32°F)		 1°C
(34°F)		 5°C
(42°F)		 11°C
(52°F)		 18°C
(64°F)		 24°C
(75°F)		 26°C
(80°F)		 26°C
(78°F)		 22°C
(72°F)		 16°C
(61°F)		 7°C
(45°F)		 3°C
(37°F)
Daily mean -3°C
(27°F)		 -3°C
(28°F)		 1°C
(35°F)		 7°C
(45°F)		 13°C
(57°F)		 20°C
(68°F)		 23°C
(73°F)		 22°C
(72°F)		 18°C
(65°F)		 12°C
(54°F)		 4°C
(40°F)		 0°C
(33°F)
Average low -6°C
(22°F)		 -6°C
(22°F)		 -2°C
(28°F)		 3°C
(38°F)		 9°C
(49°F)		 16°C
(60°F)		 19°C
(66°F)		 18°C
(65°F)		 14°C
(58°F)		 9°C
(49°F)		 2°C
(35°F)		 -2°C
(29°F)
Mean minimum -16°C
(4°F)		 -16°C
(3°F)		 -10°C
(14°F)		 -2°C
(28°F)		 2°C
(36°F)		 11°C
(52°F)		 14°C
(58°F)		 13°C
(56°F)		 8°C
(47°F)		 2°C
(36°F)		 -6°C
(22°F)		 -10°C
(15°F)
Minimum -23°C
(-10°F)		 -24°C
(-11°F)		 -14°C
(6°F)		 -5°C
(24°F)		 -1°C
(31°F)		 8°C
(47°F)		 13°C
(55°F)		 12°C
(54°F)		 5°C
(40°F)		 0°C
(32°F)		 -10°C
(14°F)		 -18°C
(0°F)

Compare climate in Sarnia with other places

Compare temperature, precipitation, sunshine, UV index in Sarnia, Ontario, Canada with other places around the world.

Monthly average precipitation in Sarnia, Ontario, Canada §

Sarnia usually has the most precipitation in April, May and October, with an average of 13 rainy days and 99 mm (3.9 inches) of precipitation per month.The driest months in Sarnia are January, March and December. On average, 59 mm (2.3 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Sarnia, Ontario, Canada.Generated using Copernicus Climate Change Service information.Data for period from January 2017 to January 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Average precipitation mm (inches) 60 (2.4) 66 (2.6) 63 (2.5) 95 (3.7) 97 (3.8) 86 (3.4) 73 (2.9) 79 (3.1) 73 (2.9) 106 (4.2) 72 (2.8) 55 (2.2)
Average precipitation days (≥ 1 mm) 8 10 10 14 13 11 11 11 10 14 10 10

Monthly sunshine hours in Sarnia, Ontario, Canada §

The sunniest months in Sarnia are June, July and August, when the sun shines an average of 11 hours 10 minutes a day.Least sunny months in Sarnia: January, February and December receive an average of 4 hours 11 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Sarnia, Ontario, Canada.Generated using Copernicus Atmosphere Monitoring Service information.Data for period from January 2017 to January 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Mean monthly sunshine hours 104 155 236 246 293 341 353 332 287 214 157 122
Mean daily daylight hours 9h 24m 10h 32m 11h 57m 13h 25m 14h 40m 15h 17m 14h 57m 13h 50m 12h 26m 10h 58m 9h 42m 9h 3m

Solar UV radiation in Sarnia, Ontario, Canada §

Sarnia experiences the highest level of ultraviolet (UV) radiation in May, June and August, when the maximum UV index can reach values of 9 - 10, which corresponds to the Very High category of sun exposure.January, November and December are in the Low / Moderate exposure category. In these months, the maximum values of the UV index do not exceed 3. For more detailed information, check out our hourly Sarnia UV Index data.

Average daily maximum UV levels by month for Sarnia, Ontario, Canada.Generated using Copernicus Atmosphere Monitoring Service information.Data for period from January 2022 to January 2023.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
UV Index (month maximum) 2 4 5 8 9 10 9 9 7 5 3 2