St. Peters weather in September: St. Peters, Missouri: normal highs, lows, rain and records for September
St. Peters in September has a normal high of 81°F and a normal low of 57°F, a daily mean of 69°F, falling from 85°F on the 1st to 75°F by the 30th. Measurable precipitation falls on 8 days in a normal September, 3.07 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 27°C and low of 14°C, 78 mm of precipitation in September.
- NOAA stationSt Peters (2 mi SE)
- Station IDUSC00237475
- Location38.77°N 90.59°W
- Elevation575 ft (175 m)
- From the center1 miles
- Population61,398
- Jan 39° 21°
- Feb 45° 25°
- Mar 56° 33°
- Apr 67° 43°
- May 76° 54°
- Jun 84° 63°
- Jul 88° 68°
- Aug 87° 65°
- Sep 81° 57°
- Oct 69° 45°
- Nov 55° 35°
- Dec 44° 27°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is St. Peters in September?
The normal high is 81°F and the normal low 57°F, for a daily mean of 68.9°F. September is 7.4°F cooler than August and 12.0°F warmer than October. September is the 4th warmest month of the year in St. Peters and the 9th wettest. Across the month the normal high falls 10°F, from 85°F on September 1 to 75°F on September 30. From one year to the next September's mean temperature typically moves about 2.9°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 66°F and 72°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 27%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 85°F | 62°F | 27% | 18% |
| September 8 | 84°F | 60°F | 27% | 18% |
| September 15 | 81°F | 58°F | 27% | 18% |
| September 22 | 79°F | 55°F | 27% | 17% |
| September 30 | 75°F | 51°F | 25% | 17% |
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 | 85°F | 62°F | 27% | 18% | 13 h |
| September 2 | 85°F | 62°F | 27% | 18% | 13 h |
| September 3 | 85°F | 62°F | 27% | 18% | 13 h |
| September 4 | 85°F | 62°F | 27% | 18% | 13 h |
| September 5 | 84°F | 61°F | 27% | 18% | 12 h 50 min |
| September 6 | 84°F | 61°F | 27% | 18% | 12 h 50 min |
| September 7 | 84°F | 61°F | 27% | 18% | 12 h 50 min |
| September 8 | 84°F | 60°F | 27% | 18% | 12 h 50 min |
| September 9 | 83°F | 60°F | 27% | 18% | 12 h 40 min |
| September 10 | 83°F | 59°F | 27% | 18% | 12 h 40 min |
| September 11 | 83°F | 59°F | 27% | 18% | 12 h 40 min |
| September 12 | 82°F | 59°F | 27% | 18% | 12 h 40 min |
| September 13 | 82°F | 58°F | 27% | 18% | 12 h 40 min |
| September 14 | 82°F | 58°F | 27% | 18% | 12 h 30 min |
| September 15 | 81°F | 58°F | 27% | 18% | 12 h 30 min |
| September 16 | 81°F | 57°F | 27% | 18% | 12 h 30 min |
| September 17 | 81°F | 57°F | 27% | 18% | 12 h 30 min |
| September 18 | 80°F | 56°F | 27% | 18% | 12 h 20 min |
| September 19 | 80°F | 56°F | 27% | 18% | 12 h 20 min |
| September 20 | 79°F | 55°F | 27% | 18% | 12 h 20 min |
| September 21 | 79°F | 55°F | 27% | 18% | 12 h 20 min |
| September 22 | 79°F | 55°F | 27% | 17% | 12 h 10 min |
| September 23 | 78°F | 54°F | 26% | 17% | 12 h 10 min |
| September 24 | 78°F | 54°F | 26% | 17% | 12 h 10 min |
| September 25 | 77°F | 53°F | 26% | 17% | 12 h 10 min |
| September 26 | 77°F | 53°F | 26% | 17% | 12 h |
| September 27 | 77°F | 53°F | 26% | 17% | 12 h |
| September 28 | 76°F | 52°F | 26% | 17% | 12 h |
| September 29 | 76°F | 52°F | 26% | 17% | 12 h |
| September 30 | 75°F | 51°F | 25% | 17% | 11 h 50 min |
- Normal high
- 81°FSeptember average
- Normal low
- 57°FSeptember average
- Precipitation
- 3.07 inmonth total
- Days with precipitation
- 80.01 inch or more
- Days at 90°F or more
- 4
- Daylight
- 13 h to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 26
- Days at 80°F or more
- 16
- Sunshine
- 81%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USC00237475; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in St. Peters in September?
On a given September day the chance of 0.01 inch or more is 27% on average, highest around September 1 (27%). In all, 3.07 in falls on 8 days of a normal September, 1 of them with an inch or more.
In a normal September in St. Peters, 4 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USC00237475.
How does September in St. Peters compare across Missouri?
Across the 134 places PlainClimate covers in Missouri, September normal highs run from 76°F in Unionville to 85°F in Kennett; St. Peters's is 81°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.