Weather & Climate in Harriston, ON
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Harriston has a cool climate with an average annual temperature of 43°F (6°C). Winters average 18°F in January while summers reach 67°F in July. Annual precipitation totals 42.1 inches. The area receives 13.2 inches of snow annually. The city sits at an elevation of 1,260 feet.
Temperature
18°F Jan (-8°C)
67°F Jul (19°C)
| Annual Average | 43.0°F |
| 20% below US avg | |
| January Average | 18°F (-8°C) |
| July Average | 67°F (19°C) |
Geography
| Elevation | 1,260 ft (384 m) |
| Area | 258.2 sq mi (668.7 km²) |
| Population Density | 7/sq mi |
| Coordinates | 43.9120°N, 80.8720°W |
| Timezone | America/Toronto |
Precipitation & Snow
Air Quality
Earthquake History
3 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.1.
| May 24, 2000 | 4 km ENE of Centennial Scarborough, Canada | M3.1 | 143 km | 18 km |
| Mar 28, 2005 | 16 km NW of Virgil, Canada | M2.8 | 144 km | 7 km |
| Sep 20, 2009 | 20 km ESE of Oakville, Canada | M2.6 | 129 km | 4 km |
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Tsunami History
1 tsunami recorded within 500 km. Highest wave on record: 2.7 m (9 ft).
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 1855 | OWEN SOUND, LAKE HURON | Unknown | 2.7 m | - | 121 km |
Source: NOAA/NCEI Historical Tsunami Database.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 18°F (-8°C) | 3.8 in | Coldest |
| February | 18°F (-8°C) | 2.9 in | |
| March | 27°F (-3°C) | 2.7 in | Driest |
| April | 40°F (5°C) | 3.0 in | |
| May | 53°F (12°C) | 3.5 in | |
| June | 62°F (16°C) | 3.2 in | |
| July | 67°F (19°C) | 3.5 in | Warmest |
| August | 65°F (18°C) | 3.9 in | |
| September | 58°F (15°C) | 4.2 in | Wettest |
| October | 47°F (9°C) | 3.6 in | |
| November | 36°F (2°C) | 4.1 in | |
| December | 25°F (-4°C) | 3.8 in |
Harriston has a seasonal temperature swing of 48°F / from 18°F in January to 67°F in July. Total annual precipitation is 42.1 inches, with September being the wettest month (4.2") and March the driest (2.7").