FPUS42 KMLB 251013 City Forecast for Sanford, FL Issued Wednesday morning - Nov 25, 2009 .Wednesday... Thunderstorm, high 77, 90% chance of precipitation. .Wednesday night... Low 59, 50% chance of precipitation. .Thursday... Partly cloudy, high 73, 20% chance of precipitation. .Thursday night... Low 46. .Friday... High 66.