Record Low for STL Tonight 54 in 1971-John Fuller’s Forecast for Metro St. Louis- Tonight:  Becoming Clear, almost chilly, Low 59.  Tuesday:  Sunny AM, Partly cloudy PM, Sun Index 8, Wind NW 10-15, High 82, Low 63.  Wednesday:  Fair, High 85, Low 65.  Thursday:  Partly cloudy, High 86, Low 66.