FPUS43 KDMX 162107 City Forecast for Waterloo, IA Issued Tuesday afternoon - Aug 16, 2011 .Tuesday night... Low 66, 40% chance of precipitation. .Wednesday... Partly cloudy, high 80, 10% chance of precipitation. .Wednesday night... Low 56, 5% chance of precipitation. .Thursday... Sunny, high 82. .Thursday night... Low 62.