Custer weather in September: Custer, South Dakota: normal highs, lows, rain and records for September
Custer in September has a normal high of 69°F and a normal low of 43°F, a daily mean of 56°F, falling from 75°F on the 1st to 61°F by the 30th. Measurable precipitation falls on 8 days in a normal September, 1.59 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 21°C and low of 6°C, 40 mm of precipitation in September.
- NOAA stationCuster County Airport
- Station IDUSW00094032
- Location43.73°N 103.61°W
- Elevation5,545 ft (1,690 m)
- Population1,829
- Jan 35° 15°
- Feb 35° 15°
- Mar 44° 22°
- Apr 50° 29°
- May 60° 38°
- Jun 71° 47°
- Jul 79° 54°
- Aug 78° 52°
- Sep 69° 43°
- Oct 54° 32°
- Nov 43° 22°
- Dec 35° 16°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Custer in September?
The normal high is 69°F and the normal low 43°F, for a daily mean of 55.9°F. September is 8.8°F cooler than August and 12.9°F warmer than October. September is the 4th warmest month of the year in Custer and the 6th wettest. Across the month the normal high falls 14°F, from 75°F on September 1 to 61°F on September 30. From one year to the next September's mean temperature typically moves about 2.8°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 53°F and 59°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 28%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 75°F | 48°F | 27% | 13% |
| September 8 | 73°F | 46°F | 27% | 13% |
| September 15 | 70°F | 43°F | 27% | 13% |
| September 22 | 66°F | 41°F | 28% | 13% |
| September 30 | 61°F | 38°F | 28% | 13% |
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 | 75°F | 48°F | 27% | 13% | 13 h 20 min |
| September 2 | 75°F | 48°F | 27% | 13% | 13 h 10 min |
| September 3 | 75°F | 47°F | 27% | 13% | 13 h 10 min |
| September 4 | 74°F | 47°F | 27% | 13% | 13 h 10 min |
| September 5 | 74°F | 47°F | 27% | 13% | 13 h |
| September 6 | 74°F | 46°F | 27% | 13% | 13 h |
| September 7 | 73°F | 46°F | 27% | 13% | 13 h |
| September 8 | 73°F | 46°F | 27% | 13% | 13 h |
| September 9 | 73°F | 45°F | 27% | 13% | 12 h 50 min |
| September 10 | 72°F | 45°F | 27% | 13% | 12 h 50 min |
| September 11 | 72°F | 45°F | 27% | 13% | 12 h 50 min |
| September 12 | 71°F | 44°F | 27% | 13% | 12 h 40 min |
| September 13 | 71°F | 44°F | 27% | 13% | 12 h 40 min |
| September 14 | 70°F | 44°F | 27% | 13% | 12 h 40 min |
| September 15 | 70°F | 43°F | 27% | 13% | 12 h 30 min |
| September 16 | 69°F | 43°F | 27% | 13% | 12 h 30 min |
| September 17 | 69°F | 43°F | 28% | 13% | 12 h 30 min |
| September 18 | 68°F | 42°F | 28% | 13% | 12 h 30 min |
| September 19 | 68°F | 42°F | 28% | 13% | 12 h 20 min |
| September 20 | 67°F | 41°F | 28% | 13% | 12 h 20 min |
| September 21 | 66°F | 41°F | 28% | 13% | 12 h 20 min |
| September 22 | 66°F | 41°F | 28% | 13% | 12 h 10 min |
| September 23 | 65°F | 40°F | 28% | 13% | 12 h 10 min |
| September 24 | 65°F | 40°F | 28% | 13% | 12 h 10 min |
| September 25 | 64°F | 40°F | 28% | 13% | 12 h 10 min |
| September 26 | 64°F | 39°F | 28% | 13% | 12 h |
| September 27 | 63°F | 39°F | 28% | 13% | 12 h |
| September 28 | 62°F | 38°F | 28% | 13% | 12 h |
| September 29 | 62°F | 38°F | 28% | 13% | 11 h 50 min |
| September 30 | 61°F | 38°F | 28% | 13% | 11 h 50 min |
- Normal high
- 69°FSeptember average
- Normal low
- 43°FSeptember average
- Precipitation
- 1.59 inmonth total
- Days with precipitation
- 80.01 inch or more
- Nights at 32°F or colder
- 3
- Daylight
- 13 h 20 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 16
- Days at 80°F or more
- 6
- Sunshine
- 83%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00094032; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Custer in September?
On a given September day the chance of 0.01 inch or more is 27% on average, highest around September 20 (28%). In all, 1.59 in falls on 8 days of a normal September.
In a normal September in Custer, 3 nights fall to freezing.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00094032.
How humid and windy is Custer in September?
At 3 p.m. the normal temperature is 59°F with 36% relative humidity and a dew point of 33°F; at 6 a.m. it is 42°F with 66% humidity. The wind averages 6.2 mph, most often from the west in the afternoon. A dew point under 50°F feels dry.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 42°F | 31°F | 66% | 4.9 mph | – |
| 9 a.m. | 54°F | 33°F | 45% | 7.4 mph | – |
| noon | 59°F | 32°F | 36% | 9.0 mph | – |
| 3 p.m. | 59°F | 33°F | 36% | 9.0 mph | – |
| 6 p.m. | 52°F | 33°F | 48% | 5.0 mph | – |
| 9 p.m. | 45°F | 32°F | 60% | 4.7 mph | – |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00094032. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for September in Custer?
The warmest September temperature on this station's record (since 1999) is 94°F, on September 5, 2020; the coldest is 21°F, on September 9, 2020. The wettest September brought 4.42 in (2014).
The September mean against the 1991-2020 normal of 55.9°F: 2021 60.0°F (+4.1), 2022 60.7°F (+4.8), 2023 59.4°F (+3.5), 2024 62.6°F (+6.7), 2025 58.8°F (+2.9), 2026 59.6°F (+3.7). 6 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 60.0°F | +4.1°F | 1.18 in |
| 2022 | 60.7°F | +4.8°F | 0.46 in |
| 2023 | 59.4°F | +3.5°F | 2.13 in |
| 2024 | 62.6°F | +6.7°F | 1.69 in |
| 2025 | 58.8°F | +2.9°F | 0.81 in |
| 2026 | 59.6°F | +3.7°F | 3.09 in |
Source: records: ACIS, station USW00094032; recent months: ACIS, station USW00094032. Records and recent months use complete months only.
How does September in Custer compare across South Dakota?
Across the 100 places PlainClimate covers in South Dakota, September normal highs run from 69°F in Custer to 82°F in Interior; Custer's is 69°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.