Weather & Climate in Perth South, ON
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Perth South has a cool climate with an average annual temperature of 45°F (7°C). Winters average 20°F in January while summers reach 68°F in July. Annual precipitation totals 40.8 inches. The area receives 12.4 inches of snow annually. The city sits at an elevation of 1,093 feet.
Temperature
20°F Jan (-7°C)
68°F Jul (20°C)
| Annual Average | 44.6°F |
| 17% below US avg | |
| January Average | 20°F (-7°C) |
| July Average | 68°F (20°C) |
Geography
| Elevation | 1,093 ft (333 m) |
| Area | 151.3 sq mi (391.9 km²) |
| Population Density | 25/sq mi |
| Coordinates | 43.3117°N, 81.1365°W |
| Timezone | America/Toronto |
Precipitation & Snow
Air Quality
Earthquake History
3 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M2.8.
| Mar 28, 2005 | 16 km NW of Virgil, Canada | M2.8 | 150 km | 7 km |
| Sep 20, 2009 | 20 km ESE of Oakville, Canada | M2.6 | 138 km | 4 km |
| May 23, 2022 | 2 km NNW of Corunna, Canada | M2.5 | 116 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Tsunami History
2 tsunamis recorded within 500 km. Highest wave on record: 2.7 m (9 ft).
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 1823 | LAKE ERIE | Unknown | 2.7 m | - | 114 km |
| 1952 | LAKE HURON, MI | Avalanche | 1.5 m | - | 105 km |
Source: NOAA/NCEI Historical Tsunami Database.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 20°F (-7°C) | 3.2 in | Coldest |
| February | 21°F (-6°C) | 2.6 in | Driest |
| March | 30°F (-1°C) | 2.9 in | |
| April | 42°F (6°C) | 3.2 in | |
| May | 55°F (13°C) | 3.4 in | |
| June | 64°F (18°C) | 3.2 in | |
| July | 68°F (20°C) | 3.5 in | Warmest |
| August | 67°F (19°C) | 3.5 in | |
| September | 60°F (15°C) | 4.1 in | Wettest |
| October | 48°F (9°C) | 3.5 in | |
| November | 37°F (3°C) | 4.1 in | |
| December | 26°F (-3°C) | 3.7 in |
Perth South has a seasonal temperature swing of 48°F / from 20°F in January to 68°F in July. Total annual precipitation is 40.8 inches, with September being the wettest month (4.1") and February the driest (2.6").