Sumter weather in September: Sumter, South Carolina: normal highs, lows, rain and records for September
Sumter in September has a normal high of 83°F and a normal low of 63°F, a daily mean of 73°F, falling from 87°F on the 1st to 79°F by the 30th. Measurable precipitation falls on 9 days in a normal September, 4.36 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 29°C and low of 17°C, 111 mm of precipitation in September.
- NOAA stationSumter
- Station IDUSC00388440
- Location33.94°N 80.36°W
- Elevation177 ft (54 m)
- Population42,958
- Jan 55° 33°
- Feb 59° 35°
- Mar 66° 41°
- Apr 75° 50°
- May 81° 58°
- Jun 87° 66°
- Jul 90° 70°
- Aug 89° 68°
- Sep 83° 63°
- Oct 74° 51°
- Nov 65° 40°
- Dec 57° 35°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Sumter in September?
The normal high is 83°F and the normal low 63°F, for a daily mean of 73.2°F. September is 5.3°F cooler than August and 10.6°F warmer than October. September is the 4th warmest month of the year in Sumter and the 4th wettest. Across the month the normal high falls 8°F, from 87°F on September 1 to 79°F on September 30. From one year to the next September's mean temperature typically moves about 2.1°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 71°F and 75°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 31%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 87°F | 67°F | 31% | 20% |
| September 8 | 85°F | 65°F | 29% | 19% |
| September 15 | 84°F | 63°F | 28% | 19% |
| September 22 | 82°F | 61°F | 29% | 19% |
| September 30 | 79°F | 58°F | 28% | 18% |
Every day of September: normal high, low and chance of precipitation (warmest afternoon September 1, coldest night September 30)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| September 1 | 87°F | 67°F | 31% | 20% | 12 h 50 min |
| September 2 | 87°F | 66°F | 31% | 20% | 12 h 50 min |
| September 3 | 86°F | 66°F | 30% | 20% | 12 h 50 min |
| September 4 | 86°F | 66°F | 30% | 20% | 12 h 50 min |
| September 5 | 86°F | 66°F | 30% | 19% | 12 h 50 min |
| September 6 | 86°F | 66°F | 30% | 19% | 12 h 40 min |
| September 7 | 86°F | 65°F | 30% | 19% | 12 h 40 min |
| September 8 | 85°F | 65°F | 29% | 19% | 12 h 40 min |
| September 9 | 85°F | 65°F | 29% | 19% | 12 h 40 min |
| September 10 | 85°F | 65°F | 29% | 19% | 12 h 40 min |
| September 11 | 85°F | 65°F | 29% | 19% | 12 h 30 min |
| September 12 | 85°F | 64°F | 29% | 19% | 12 h 30 min |
| September 13 | 84°F | 64°F | 29% | 18% | 12 h 30 min |
| September 14 | 84°F | 64°F | 29% | 19% | 12 h 30 min |
| September 15 | 84°F | 63°F | 28% | 19% | 12 h 30 min |
| September 16 | 84°F | 63°F | 28% | 19% | 12 h 20 min |
| September 17 | 83°F | 63°F | 28% | 19% | 12 h 20 min |
| September 18 | 83°F | 63°F | 28% | 19% | 12 h 20 min |
| September 19 | 83°F | 62°F | 28% | 19% | 12 h 20 min |
| September 20 | 82°F | 62°F | 28% | 19% | 12 h 20 min |
| September 21 | 82°F | 62°F | 29% | 19% | 12 h 10 min |
| September 22 | 82°F | 61°F | 29% | 19% | 12 h 10 min |
| September 23 | 82°F | 61°F | 29% | 19% | 12 h 10 min |
| September 24 | 81°F | 60°F | 29% | 19% | 12 h 10 min |
| September 25 | 81°F | 60°F | 28% | 19% | 12 h 10 min |
| September 26 | 81°F | 60°F | 28% | 19% | 12 h |
| September 27 | 80°F | 59°F | 28% | 19% | 12 h |
| September 28 | 80°F | 59°F | 28% | 18% | 12 h |
| September 29 | 80°F | 58°F | 28% | 18% | 12 h |
| September 30 | 79°F | 58°F | 28% | 18% | 11 h 50 min |
- Normal high
- 83°FSeptember average
- Normal low
- 63°FSeptember average
- Precipitation
- 4.36 inmonth total
- Days with precipitation
- 90.01 inch or more
- Days at 90°F or more
- 6
- Daylight
- 12 h 50 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 29
- Days at 80°F or more
- 23
- Sunshine
- 79%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USC00388440; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Sumter in September?
On a given September day the chance of 0.01 inch or more is 29% on average, highest around September 1 (31%). In all, 4.36 in falls on 9 days of a normal September, 1 of them with an inch or more.
In a normal September in Sumter, 6 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USC00388440.
What are the records for September in Sumter?
The warmest September temperature on this station's record (since 1901) is 102°F, on September 5, 1944; the coldest is 38°F, on September 30, 1967. The wettest September brought 18.02 in (1945).
The September mean against the 1991-2020 normal of 73.2°F: 2021 73.9°F (+0.7), 2022 75.3°F (+2.1), 2023 74.6°F (+1.4), 2024 76.7°F (+3.5), 2025 75.3°F (+2.1). 5 of 5 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 73.9°F | +0.7°F | 3.15 in |
| 2022 | 75.3°F | +2.1°F | 2.09 in |
| 2023 | 74.6°F | +1.4°F | 2.75 in |
| 2024 | 76.7°F | +3.5°F | 2.12 in |
| 2025 | 75.3°F | +2.1°F | 2.23 in |
Source: records: ACIS, station USC00388440; recent months: ACIS, station USC00388440. Records and recent months use complete months only.
How does September in Sumter compare across South Carolina?
Across the 73 places PlainClimate covers in South Carolina, September normal highs run from 71°F in Caesars Head to 87°F in Barnwell; Sumter's is 83°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.
Other months and places
- Sumter in August89°F by day, 68°F at night
- Sumter in October74°F by day, 51°F at night
- Sumter through the yearEvery month, frost dates, records and recent years
- South Carolina in SeptemberThe statewide normal and the warmest and coolest places
- Barnwell: South Carolina's warmest Septembernormal high 87°F