Ottawa experienced a mild and drier September after the wettest summer in the capital’s history. Environment Canada released the September weather summary for Ottawa and Ontario on Friday, looking at the weather data for the past month. The average temperature in Ottawa was 15.8 C in September, just above the normal temperature of 15.3 C. Environment Canada says Ottawa received 56 mm of rain in September, well below the normal rainfall of 90 mm in the month. Ottawa has seen below normal precipitation in September over the last four years. In 2025, a total of 31.5 mm of rain was recorded at the Ottawa Airport, with 44.3 mm of rain in September 2024, 24.7 mm in September 2023 and 65.3 mm of rain in September 2022. The dry September follows the wettest summer in Ottawa’s history and the rainiest month ever. Ottawa received 282 millimetres of rain in July, setting the record for the most precipitation in a month in the capital. The previous record was 250 mm set in 1899. A total of 547.8 mm of rain fell in Ottawa in June, July and August, setting a record for most rain during the summer. Environment Canada says Ottawa and Ontario will see warmer-than-normal temperatures in October, with below-normal rainfall.
