Quincy weather in September: Quincy, Illinois: normal highs, lows, rain and records for September
Quincy in September has a normal high of 78°F and a normal low of 56°F, a daily mean of 67°F, falling from 82°F on the 1st to 73°F by the 30th. Measurable precipitation falls on 8 days in a normal September, 3.09 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 26°C and low of 13°C, 78 mm of precipitation in September.
- NOAA stationQuincy Regional Airport
- Station IDUSW00093989
- Location39.94°N 91.19°W
- Elevation769 ft (234 m)
- From the center10 miles
- Population38,786
- Jan 35° 19°
- Feb 40° 23°
- Mar 52° 32°
- Apr 64° 43°
- May 73° 54°
- Jun 82° 63°
- Jul 86° 67°
- Aug 85° 65°
- Sep 78° 56°
- Oct 65° 45°
- Nov 51° 33°
- Dec 39° 24°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Quincy in September?
The normal high is 78°F and the normal low 56°F, for a daily mean of 67.0°F. September is 7.5°F cooler than August and 11.9°F warmer than October. September is the 4th warmest month of the year in Quincy and the 6th wettest. Across the month the normal high falls 9°F, from 82°F on September 1 to 73°F on September 30. From one year to the next September's mean temperature typically moves about 3.2°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 64°F and 70°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 | 82°F | 61°F | 26% | 16% |
| September 8 | 81°F | 59°F | 26% | 16% |
| September 15 | 78°F | 56°F | 26% | 17% |
| September 22 | 76°F | 54°F | 26% | 17% |
| September 30 | 73°F | 51°F | 27% | 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 | 82°F | 61°F | 26% | 16% | 13 h 10 min |
| September 2 | 82°F | 61°F | 26% | 16% | 13 h |
| September 3 | 82°F | 61°F | 26% | 16% | 13 h |
| September 4 | 82°F | 60°F | 26% | 16% | 13 h |
| September 5 | 81°F | 60°F | 26% | 16% | 13 h |
| September 6 | 81°F | 60°F | 26% | 16% | 12 h 50 min |
| September 7 | 81°F | 59°F | 26% | 16% | 12 h 50 min |
| September 8 | 81°F | 59°F | 26% | 16% | 12 h 50 min |
| September 9 | 80°F | 59°F | 26% | 17% | 12 h 50 min |
| September 10 | 80°F | 58°F | 26% | 17% | 12 h 40 min |
| September 11 | 80°F | 58°F | 26% | 17% | 12 h 40 min |
| September 12 | 79°F | 58°F | 26% | 17% | 12 h 40 min |
| September 13 | 79°F | 57°F | 26% | 17% | 12 h 40 min |
| September 14 | 79°F | 57°F | 26% | 17% | 12 h 30 min |
| September 15 | 78°F | 56°F | 26% | 17% | 12 h 30 min |
| September 16 | 78°F | 56°F | 26% | 17% | 12 h 30 min |
| September 17 | 78°F | 56°F | 26% | 17% | 12 h 30 min |
| September 18 | 77°F | 55°F | 26% | 17% | 12 h 20 min |
| September 19 | 77°F | 55°F | 26% | 17% | 12 h 20 min |
| September 20 | 77°F | 55°F | 26% | 17% | 12 h 20 min |
| September 21 | 76°F | 54°F | 26% | 17% | 12 h 20 min |
| September 22 | 76°F | 54°F | 26% | 17% | 12 h 10 min |
| September 23 | 75°F | 53°F | 26% | 17% | 12 h 10 min |
| September 24 | 75°F | 53°F | 26% | 17% | 12 h 10 min |
| September 25 | 75°F | 53°F | 26% | 17% | 12 h 10 min |
| September 26 | 74°F | 52°F | 26% | 17% | 12 h |
| September 27 | 74°F | 52°F | 26% | 17% | 12 h |
| September 28 | 73°F | 51°F | 26% | 17% | 12 h |
| September 29 | 73°F | 51°F | 26% | 17% | 11 h 50 min |
| September 30 | 73°F | 51°F | 27% | 17% | 11 h 50 min |
- Normal high
- 78°FSeptember average
- Normal low
- 56°FSeptember average
- Precipitation
- 3.09 inmonth total
- Days with precipitation
- 80.01 inch or more
- Days at 90°F or more
- 3
- Daylight
- 13 h 10 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 25
- Days at 80°F or more
- 13
- Sunshine
- 82%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00093989; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Quincy in September?
On a given September day the chance of 0.01 inch or more is 26% on average, highest around September 30 (27%). In all, 3.09 in falls on 8 days of a normal September, 1 of them with an inch or more.
In a normal September in Quincy, 3 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00093989.
What are the records for September in Quincy?
The warmest September temperature on Quincy's official record (since 1901) is 105°F, on September 4, 1913; the coldest is 26°F, on September 28, 1942. The wettest September brought 11.64 in (1926).
The September mean against the 1991-2020 normal of 67.0°F: 2021 71.2°F (+4.2), 2022 68.2°F (+1.2), 2023 70.1°F (+3.1), 2024 69.8°F (+2.8), 2025 70.0°F (+3.0), 2026 73.9°F (+6.9). 6 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 71.2°F | +4.2°F | 1.47 in |
| 2022 | 68.2°F | +1.2°F | 4.18 in |
| 2023 | 70.1°F | +3.1°F | 0.35 in |
| 2024 | 69.8°F | +2.8°F | 2.20 in |
| 2025 | 70.0°F | +3.0°F | 1.01 in |
| 2026 | 73.9°F | +6.9°F | 2.56 in |
Source: records: ACIS, NWS threaded record UINthr; recent months: ACIS, station USW00093989. Records and recent months use complete months only.
How does September in Quincy compare across Illinois?
Across the 144 places PlainClimate covers in Illinois, September normal highs run from 72°F in Barrington to 84°F in Anna; Quincy's is 78°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.