Army Airfield, USA). Calendar Forecast Detailed Forecast Sep October 2023 Nov October 2023 Summary Precipitation Forecast Average Precipitation Temperature Forecast Normal Avg High Temps 70 to 85 ° Avg Low Temps 55 to 65 ° Avg High Temps 20 to 30 ° Avg Low Temps 10 to 20 ° Rain Frequency 3 to 5 days Click or Tap on any day for a detailed forecast. Hilton Head Island, SC Hourly Weather | AccuWeather 7 PM 76° RealFeel® 75° 49% Cloudy alerts Coastal Flood Advisory 5:00 PM Wednesday - 9:00 PM Wednesday RealFeel Shade™ 75° Wind ENE 12 mph Air.