South Simcoe Forecast for Thursday May 2 New Tecumseth, ON, Canada / FM92 South Simcoe Today Adrianne Proceviat May 2, 2024 | 6:40 AM Chris Fithall / CC A mix of sun and cloud today… High 20. Clear sky this evening… Low 9. Clouding over tomorrow morning…. Chance of showers or a thunderstorm late in the day… High 22.