Sarnia (ON) Monthly Rainfall & Precipitation

This page shows both the average monthly rainfall and the number of rainy days in Sarnia, Ontario, Canada. These averages rely on historical data collected over 30 years, from 1990 to 2020. Now, let's explore all the details to give you a full picture.

Generally, Sarnia experiences moderate precipitation patterns, averaging 970 mm (38 in) yearly.

Monthly Precipitation Levels

The average number of days each month with precipitation (> 0.2 mm (0.01 in))

Despite minor fluctuations, Sarnia enjoys fairly consistent precipitation throughout the year. In June, you can expect around 97 mm (3.8 in) of precipitation, while in March, Sarnia receives about 66 mm (2.6 in).

June, the wettest month, has a maximum daytime temperature of 25°C (77°F). During the driest month March you can expect a temperature of 6°C (43°F). For more detailed insights into the city's temperatures, visit our Sarnia Temperature page.

Sarnia's average annual precipitation is 970 mm (38 in). Let's compare this to some popular worldwide tourist destinations:

Boston, USA, experiences 1238 mm (49 in) of annual precipitation, including significant snowfall during the winter.

Meanwhile, Buenos Aires, Argentina, enjoys a humid subtropical climate with 1000 mm (39 in) of annual rainfall, mostly in the summer.

Adelaide, Australia, enjoys 511 mm (20 in) of annual precipitation, with dry summers and wet winters.

Singapore, situated near the equator, gets 2581 mm (102 in) of rainfall annually, with no distinct dry season and consistent monthly precipitation.

Precipitation amounts are measured using specific gauges installed at weather stations, collecting both rain and snow and any other type of precipitation. Rainfall is measured directly in millimeters, while that from snow and ice is obtained by melting it. Automated systems often incorporate heaters to make this easier.

Information from these stations is transmitted via Wi-Fi, satellite, GPS, or telephone connections to central monitoring networks. This information is immediately updated and integrated into weather models and forecasts.

Climate change is affecting precipitation patterns worldwide, including Sarnia (ON):

• Changing Rainfall Patterns: Global warming causes drastic changes in the patterns of rainfall. Some areas have been experiencing increased frequency and intensity of rainfall, while other areas experience longer dry spells or even droughts.
• Local Impacts: Many regions are experiencing heavier rainfall in the winter months and drier, hotter summers. This affects agriculture, water resources, and ecosystems.

• The U.S. has a significant number of thunderstorms every year, with over 14.6 million taking place across the world annually.
• Approximately 70% of lightning bolts strike land rather than oceans.
• A storm named John was the longest-lasting Pacific tropical storm, continuing for 31 days. As it crossed the dateline twice, it changed status from a hurricane to a typhoon and back to a hurricane.

For more detailed information about Sarnia (ON)'s weather, including sunshine hours, humidity levels, and temperature data, visit our Sarnia (ON) Climate page.