Hilton Head Island Weather in September
September continues the hot summer weather at Hilton Head Island in South Carolina. But the resort town is less rainy now than earlier in the season.
This page gives detailed information on the typical September weather for Hilton Head Island. The temperature and rainfall numbers here are historical averages based on climate data gathered at Hilton Head Island. The humidity and sunshine measurements are averages from the Savannah / Hilton Head International Airport.
Temperature
| 84 °F | September average high | 29 °C |
| 69 °F | September average low | 21 °C |
In most years, Hilton Head Island averages a daily maximum temperature for September that's between 82 and 86 degrees Fahrenheit (28 to 30 degrees Celsius). The minimum temperature usually falls between 67 and 71 °F (20 to 22 °C).
The days at Hilton Head Island start to cool down quickly during September. By the end of the month, the temperature has dropped around 7 °F (4 °C) below what it was at the start.
| 24 days | 80 °F max. or more (27 °C) |
| 15 days | 70 °F min. or less (21 °C) |
Usually every day during September the temperature rises to over 70 °F (21 °C) at Hilton Head. The Island averages 3 days this month when the thermometer reaches into the 90s °F (over 32 °C). Temperatures above 100 °F (38 °C) are not expected here during September.
The thermometer dips to 60 °F (16 °C) or below on an average of 2 nights. But September does not normally get as cold as 50 °F (10 °C).
Rain
| 5.8 in | total precipitation | 148 mm |
| 10 days | of rain |
Half the time, Hilton Head Island receives 4 to 8 inches (102 to 197 mm) of rainfall in September. One in four years has drier weather, while another one in four is wetter.
Sun
| 58 % | sunshine |
| 7 days | clear skies |
The sun's rays reach the ground in Hilton Head Island during 58 percent of daylight hours on average in September, for a total of 215 hours in the month. Typically on 7 days this month the sky is mainly clear, with at most 30 percent cloud cover.
Sunlight in September at the beach town lasts for 12 hours and 20 minutes a day on average. The longest day of the month is the 1st with 12 hours and 49 minutes of daylight. By the end of the month, the days have shortened to 11:52 from sunrise to sunset. These durations can vary by a minute or two from year to year.
Humidity
| 78 % | September average humidity |
The relative humidity in Hilton Head Island during September usually peaks at 91 percent in the morning then drops to 60 percent by early afternoon.
| Local Time | 1 am | 4 am | 7 am | 10 am | 1 pm | 4 pm | 7 pm | 10 pm |
| Humidity % | 88 | 90 | 91 | 71 | 60 | 61 | 76 | 85 |
Storms
| 4 days | rainfall of 0.5 inches (13 mm) or more |
| 12 % | chance a named storm approaches |
There's a 4 percent probability that a hurricane will approach within 100 miles (165 km) of Hilton Head Island during September. The chance of a major category 3 to 5 hurricane reaching the area is 1 percent.
Reference
These weather data are long-term historical averages provided by the National Climatic Data Center of the United States. The temperature and precipitation numbers are 1981-2010 normals while the humidity statistics are 1961-1990 normals. The named storm probabilities come from the Atlantic Oceanographic and Meteorological Laboratory, Hurricane Research Division.