Weather on September 15 in Ottawa
Historical weather data for September 15 in Ottawa, Canada
Based on 54 years of data from OTTAWA CDA
About This Date
September 15th in Ottawa, Canada typically brings mild fall weather, with average highs around 19°C and lows near 9°C. Over 54 years of records, the warmest September 15th was in 2018 (23°C average), while the coldest was 2007 (8°C) — a 27°F range across recorded history. Rain or other precipitation has occurred on about 44% of September 15th dates historically, with the wettest September 15th recording 1.13" of rain. The last decade has been 4.1°F cooler on this date compared to 20-30 years ago.
The last decade has been 4.1°F cooler on this date compared to 20-30 years ago.
Planning for September 15th in Ottawa? Great weather for outdoor activities. Consider bringing rain gear or an umbrella.
Year by Year History
| Year | High | Low | Precip |
|---|---|---|---|
| 2025 | 23°C (74°F) | 11°C (51°F) | -- |
| 2023 | 21°C (70°F) | 5°C (41°F) | 0" |
| 2022 | 17°C (63°F) | 7°C (45°F) | 0" |
| 2021 | 20°C (68°F) | 11°C (51°F) | 1.13" |
| 2020 | 14°C (57°F) | 3°C (37°F) | 0.02" |
| 2019 | 17°C (62°F) | 8°C (46°F) | 0" |
| 2018 | 30°C (86°F) | 17°C (63°F) | 0" |
| 2017 | 27°C (81°F) | 12°C (54°F) | 0" |
| 2016 | 18°C (64°F) | 4°C (40°F) | 0" |
| 2015 | 27°C (81°F) | 12°C (53°F) | 0" |
| 2014 | 19°C (66°F) | 6°C (42°F) | 0.24" |
| 2013 | 19°C (66°F) | 8°C (47°F) | 0.64" |
| 2012 | 18°C (64°F) | 11°C (52°F) | 0.06" |
| 2011 | 15°C (59°F) | 7°C (45°F) | 0.09" |
| 2010 | 15°C (59°F) | 7°C (45°F) | 0" |
| 2009 | 16°C (60°F) | 11°C (52°F) | 0" |
| 2008 | 14°C (58°F) | 12°C (53°F) | 0.02" |
| 2007 | 13°C (55°F) | 4°C (39°F) | 0" |
| 2006 | 19°C (67°F) | 15°C (59°F) | 0" |
| 2005 | 24°C (76°F) | 16°C (61°F) | 0.02" |
| 2004 | 26°C (78°F) | 13°C (56°F) | 0" |
| 2003 | 26°C (79°F) | 20°C (68°F) | 0.82" |
| 2002 | 20°C (68°F) | 16°C (61°F) | 0" |
| 2001 | 20°C (68°F) | 4°C (39°F) | 0" |
| 2000 | 13°C (56°F) | 12°C (54°F) | 0.03" |
| 1999 | 23°C (74°F) | 9°C (48°F) | 0" |
| 1998 | 21°C (70°F) | 13°C (56°F) | 0.56" |
| 1997 | 23°C (73°F) | 12°C (53°F) | 0" |
| 1996 | 14°C (58°F) | 13°C (55°F) | 0.36" |
| 1995 | 16°C (60°F) | 4°C (39°F) | 0" |
| 1994 | 22°C (72°F) | 8°C (46°F) | 0.23" |
| 1993 | 13°C (56°F) | 11°C (51°F) | 0.26" |
| 1992 | 26°C (78°F) | 13°C (55°F) | 0" |
| 1991 | 22°C (71°F) | 13°C (55°F) | 0.42" |
| 1990 | 12°C (54°F) | 8°C (47°F) | 0.04" |
| 1989 | 21°C (69°F) | 9°C (48°F) | 0" |
| 1988 | 15°C (59°F) | 6°C (42°F) | 0" |
| 1987 | 22°C (71°F) | 8°C (47°F) | 0" |
| 1986 | 14°C (57°F) | 7°C (45°F) | 0.7" |
| 1985 | 21°C (70°F) | 8°C (47°F) | 0" |
| 1984 | 13°C (56°F) | 9°C (48°F) | 0" |
| 1983 | 19°C (67°F) | 5°C (41°F) | 0" |
| 1982 | 14°C (58°F) | 11°C (51°F) | 0.04" |
| 1981 | 18°C (64°F) | 8°C (46°F) | 0" |
| 1980 | 18°C (65°F) | 9°C (48°F) | 0" |
| 1979 | 18°C (64°F) | 9°C (48°F) | 0.02" |
| 1978 | 23°C (73°F) | 13°C (56°F) | 0.06" |
| 1977 | 19°C (67°F) | 4°C (40°F) | 0.08" |
| 1976 | 23°C (73°F) | 16°C (60°F) | 0" |
| 1975 | 19°C (67°F) | 7°C (44°F) | 0.03" |
| 1974 | 21°C (69°F) | 11°C (51°F) | 0" |
| 1973 | 21°C (69°F) | 8°C (46°F) | 0.05" |
| 1972 | 20°C (68°F) | 4°C (40°F) | 0" |
| 1971 | 26°C (78°F) | 17°C (63°F) | 0.05" |