Environment Canada has ended a severe thunderstorm watch for London-Middlesex, Windsor-Essex, and Chatham-Kent, along with Oxford and Elgin counties.
The storms are expected to develop late Monday afternoon with heavy rain and strong winds expected to move across much of southwestern Ontario in the evening.
According to the national weather agency, the main threat from the storms will be heavy rain and, to a lesser extent, strong winds.
The wet weather will clear out overnight with sunshine and a high of 26 C in the forecast for Tuesday.