Residents in Ajax are preparing for a sharp shift in the weather this week as forecasts from Environment Canada and The Weather Network call for thunderstorms and a significant temperature drop. While Monday, March 30, 2026, remains mild with a high of 15°C, unsettled conditions are moving into the region, bringing a risk of thunderstorms and up to 25 millimetres of rainfall through Tuesday.
This weather shift is driven by an upper wave migrating into southern Ontario, which is introducing moisture and an unstable air mass to the region. The volatility is linked to a lingering La Niña weather pattern that has persisted this spring, leading to frequent storms and inconsistent temperatures across the province.
The transition will lead to much cooler conditions by mid-week. Temperatures are expected to fall to a high of 6°C by Wednesday, April 1, with overnight lows reaching -1°C. This represents a temperature swing of approximately 15 to 16 degrees from the peak recorded on Monday.
Given the historical vulnerability of the area to heavy rainfall, local officials are closely monitoring the situation. The Central Lake Ontario Conservation Authority tracks weather forecasts and watershed conditions to predict potential flooding. The agency is responsible for issuing flood messages to municipal emergency management officials and the media when necessary.
Concerns remain heightened as Lake Ontario water levels have been at historically high levels. According to United Shorelines Ontario, significant rainfall events can exacerbate flooding risks along the waterfront, an area that has experienced past impacts from rising water. The Town of Ajax provides resources through its emergency preparation program to help residents understand these risks and strategies for safety.
