St. Simons Island, GA weather in September
St. Simons Island is warm and oppressively humid in September, with frequent rain: highs average 86°F and nights drop to about 73°F. Rain falls on about 11 days.
- Normal high
- 86°F
- Normal low
- 73°F
- Wet days
- 11
- 6.0 in total
- Muggy days
- 26
- dew point 65°F+
How September changes from start to finish
| September 1 | September 30 | |
|---|---|---|
| Normal high | 88°F | 83°F |
| Normal low | 75°F | 69°F |
| Chance of a wet day | 40% | 33% |
| Sunrise / sunset | 7:01 am / 7:49 pm | 7:18 am / 7:12 pm |
| Daylight | 12.8 h | 11.9 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Eastern Time).
A typical September day
- 6 am74°Fdew point 70°F
- 9 am79°Fdew point 71°F
- Noon83°Fdew point 71°F
- 3 pm83°Fdew point 71°F
- 6 pm80°Fdew point 71°F
- 9 pm78°Fdew point 71°F
NOAA hourly normals (local standard time) from Brunswick Malcolm Mckinnon Airport (1 mi away); average wind 8 mph.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F1 of 30
- Beach dayshigh 80-95°F, under 0.05 in of rain, afternoon wind under 15 mph18 of 30
- Hot dayshigh 90°F or more4 of 30
- Muggy daysdaily mean dew point 65°F or more26 of 30
- Wet daysat least 0.01 in of rain or melted snow11 of 30
- Notable rainat least 0.10 in8 of 30
- Freezing nightslow 32°F or below0 of 30
Average days per September, counted from daily records for each year 1991-2020.
Rain in September
Normal precipitation is 6.0 in; a dry September brings about 3.0 in and a wet one about 8.2 in (25th and 75th percentiles). About 4 days bring half an inch or more, and about 2 an inch or more.
How September varies from year to year
- Warmest September, 1991-20202018: average high 90°F
- Coolest September2001: average high 82°F
- Wettest September2017: 12.9 in
- Driest September2010: 1.5 in
- Highest reading96°F (September 5, 2020)
- Lowest reading55°F (September 30, 1993)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
September compared with August and October
| August | September | October | |
|---|---|---|---|
| Normal high | 90°F | 86°F | 79°F |
| Normal low | 76°F | 73°F | 64°F |
| Wet days | 13 | 11 | 8 |
| Comfortable days | 0 | 1 | 9 |
| Daylight | 13.3 h | 12.3 h | 11.4 h |
Highs change by -4°F from August and -7°F into October.
Nearby alternatives in September
- Warmer: Lakeland, FL217 mi · high 92°F · 15 wet days
- Drier: Macon, GA176 mi · high 88°F · 7 wet days
How St. Simons Island ranks in September
- Normal high131st warmest of 378 cities; 5th of 8 in Georgia
- Wet days327th driest of 378
- Comfortable days296th most of 342
What to pack for St. Simons Island in September
- Light, breathable clothing – highs near 86°F and about 26 muggy days
- A rain jacket or umbrella – rain on about 11 days
- A swimsuit – about 18 beach days
Heating and cooling
September has 0 heating degree days and 425 cooling degree days (base 65°F), 10% of the year's total heating and cooling demand.
Questions
How hot is St. Simons Island in September?
The normal high is 86°F and the normal low is 73°F. From 1991 to 2020 the hottest September reading was 96°F (most recently on September 5, 2020).
Does it rain a lot in St. Simons Island in September?
About 11 days in September have at least 0.01 in of precipitation, and the normal total is 6.0 in. The wettest September in 1991-2020 was in 2017 (12.9 in); the driest was in 2010 (1.5 in).
Is September a good time to visit St. Simons Island?
September ranks 10th of 12 months on our comfort score for St. Simons Island (45 out of 100). It has about 1 comfortable day and about 4 days at 90°F or hotter. The best months are March, April and November.
Where the numbers come from
- Temperature, rain, frost dates and humidity and wind by hour: Brunswick Malcolm Mckinnon Airport (USW00013878), 1.2 mi N of the city center, 16 ft . NOAA normals and daily records, 1991-2020.
- Snowfall: Brunswick (USC00091340), 7.0 mi WNW of the city center, 13 ft . NOAA normals and daily records, 1991-2020.
- Snow depth: Sapelo Is (USC00097808), 19 mi NNE of the city center, 10 ft . NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Malcolm Mc Kinnon Airport (722137-13878), 1.2 mi N of the city center, 14 ft . Hourly observations, 1991-2020.
- Not available for this location: cloud cover (no station close enough or similar enough in elevation).