Weather on September 12 in Ottawa
Historical weather data for September 12 in Ottawa, Canada
Based on 54 years of data from OTTAWA CDA RCS
About This Date
September 12th in Ottawa, Canada typically brings pleasant fall weather, with average highs around 22°C and lows near 11°C. Over 54 years of records, the warmest September 12th was in 2005 (23°C average), while the coldest was 1985 (8°C) — a 28°F range across recorded history. Rain or other precipitation has occurred on about 43% of September 12th dates historically, with the wettest September 12th recording 4.84" of rain. The last decade has been 4.3°F cooler on this date compared to 20-30 years ago.
The last decade has been 4.3°F cooler on this date compared to 20-30 years ago.
Planning for September 12th in Ottawa? Great weather for outdoor activities. Consider bringing rain gear or an umbrella.
Year by Year History
| Year | High | Low | Precip (mm) |
|---|---|---|---|
| 2025 | 21°C (70°F) | 7°C (45°F) | -- |
| 2023 | 26°C (78°F) | 12°C (54°F) | 10 mm |
| 2022 | 25°C (77°F) | 14°C (57°F) | 2 mm |
| 2021 | 23°C (73°F) | 18°C (64°F) | 0 mm |
| 2020 | 21°C (70°F) | 5°C (41°F) | 1 mm |
| 2019 | 20°C (68°F) | 9°C (48°F) | 0 mm |
| 2018 | 23°C (74°F) | 10°C (50°F) | 0 mm |
| 2017 | 26°C (78°F) | 9°C (48°F) | 0 mm |
| 2016 | 24°C (75°F) | 8°C (46°F) | 0 mm |
| 2015 | 16°C (61°F) | 13°C (55°F) | 73 mm |
| 2014 | 14°C (57°F) | 7°C (44°F) | 0 mm |
| 2013 | 24°C (76°F) | 14°C (57°F) | 48 mm |
| 2012 | 27°C (81°F) | 9°C (49°F) | 0 mm |
| 2011 | 28°C (82°F) | 13°C (56°F) | 2 mm |
| 2010 | 18°C (64°F) | 12°C (53°F) | 8 mm |
| 2009 | 24°C (76°F) | 7°C (45°F) | 0 mm |
| 2008 | 20°C (68°F) | 11°C (52°F) | 15 mm |
| 2007 | 18°C (65°F) | 9°C (48°F) | 12 mm |
| 2006 | 20°C (68°F) | 6°C (42°F) | 0 mm |
| 2005 | 31°C (88°F) | 16°C (60°F) | 0 mm |
| 2004 | 23°C (73°F) | 12°C (53°F) | 0 mm |
| 2003 | 28°C (82°F) | 17°C (62°F) | 0 mm |
| 2002 | 21°C (70°F) | 7°C (44°F) | 0 mm |
| 2001 | 25°C (77°F) | 8°C (47°F) | 22 mm |
| 2000 | 26°C (79°F) | 18°C (65°F) | 0 mm |
| 1999 | 24°C (75°F) | 9°C (49°F) | 0 mm |
| 1998 | 21°C (70°F) | 17°C (62°F) | 0 mm |
| 1997 | 24°C (75°F) | 17°C (63°F) | 1 mm |
| 1996 | 20°C (68°F) | 17°C (62°F) | 19 mm |
| 1995 | 25°C (77°F) | 6°C (43°F) | 0 mm |
| 1994 | 21°C (69°F) | 11°C (51°F) | 0 mm |
| 1993 | 21°C (69°F) | 4°C (40°F) | 2 mm |
| 1992 | 17°C (63°F) | 2°C (36°F) | 0 mm |
| 1991 | 19°C (66°F) | 5°C (41°F) | 0 mm |
| 1990 | 26°C (79°F) | 7°C (44°F) | 0 mm |
| 1989 | 24°C (76°F) | 10°C (50°F) | 0 mm |
| 1988 | 19°C (67°F) | 7°C (45°F) | 1 mm |
| 1987 | 19°C (67°F) | 18°C (64°F) | 123 mm |
| 1986 | 22°C (72°F) | 16°C (60°F) | 1 mm |
| 1985 | 13°C (55°F) | 3°C (37°F) | 1 mm |
| 1984 | 18°C (64°F) | 9°C (48°F) | 4 mm |
| 1983 | 22°C (71°F) | 10°C (50°F) | 0 mm |
| 1982 | 28°C (83°F) | 13°C (55°F) | 0 mm |
| 1981 | 22°C (71°F) | 9°C (49°F) | 0 mm |
| 1980 | 16°C (61°F) | 4°C (40°F) | 0 mm |
| 1979 | 19°C (66°F) | 6°C (43°F) | 0 mm |
| 1978 | 16°C (61°F) | 9°C (49°F) | 0 mm |
| 1977 | 18°C (64°F) | 3°C (38°F) | 43 mm |
| 1976 | 22°C (72°F) | 7°C (44°F) | 1 mm |
| 1975 | 16°C (61°F) | 11°C (52°F) | 0 mm |
| 1974 | 23°C (73°F) | 17°C (62°F) | 8 mm |
| 1973 | 18°C (64°F) | 9°C (48°F) | 1 mm |
| 1972 | 21°C (69°F) | 13°C (56°F) | 0 mm |
| 1971 | 22°C (72°F) | 18°C (65°F) | 11 mm |