South Simcoe Forecast for Friday May 3 New Tecumseth, ON, Canada / FM92 South Simcoe Today Adrianne Proceviat May 3, 2024 | 6:34 AM A_Peach / CC Clouding over today… We might see showers before noon… Risk of a thunderstorm… High 18. Cloudy this evening… chance of showers… Risk of a thunderstorm… Low 10. Mainly cloudy tomorrow… Slight chance of showers… High 23.