Largo, FL Weather Forecast. 3:02 AM EST TUE FEB 7 2017. TODAY - Patchy fog early this morning. Mostly sunny. Highs in the upper 70s. South winds 10 to 15 mph. TONIGHT - Mostly cloudy with a chance of showers and slight chance of thunderstorms. Patchy fog late in the evening. Areas of fog after midnight. Lows in the mid 60s.