London Ontario 30 Day Weather Forecast 2025 Season. Weather.com brings you the most accurate monthly weather forecast for london, ontario, canada with average/record and high/low temperatures, precipitation and more. Chance, either low or high, is not a direct prediction of rain, snow, or sleet.

See the long range weather forecast for ontario, check the 30 days forecast view, select a month and get the average expected weather for ontario. Weather.com brings you the most accurate monthly weather forecast for london, ontario with average/record and high/low temperatures, precipitation and more.