Danbury weather in September: Danbury, Connecticut: normal highs, lows, rain and records for September
Danbury in September has a normal high of 74°F and a normal low of 52°F, a daily mean of 63°F, falling from 78°F on the 1st to 68°F by the 30th. Measurable precipitation falls on 14 days in a normal September, 4.81 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 23°C and low of 11°C, 122 mm of precipitation in September.
- NOAA stationDanbury Municipal Airport
- Station IDUSW00054734
- Location41.37°N 73.48°W
- Elevation457 ft (139 m)
- From the center2 miles
- Population88,692
- Jan 36° 18°
- Feb 39° 20°
- Mar 47° 27°
- Apr 59° 37°
- May 69° 46°
- Jun 78° 56°
- Jul 82° 62°
- Aug 80° 60°
- Sep 74° 52°
- Oct 62° 41°
- Nov 51° 31°
- Dec 41° 24°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Danbury in September?
The normal high is 74°F and the normal low 52°F, for a daily mean of 62.9°F. September is 7.3°F cooler than August and 11.4°F warmer than October. September is the 4th warmest month of the year in Danbury and the wettest. Across the month the normal high falls 10°F, from 78°F on September 1 to 68°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 61°F and 65°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 47%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 78°F | 57°F | 43% | 19% |
| September 8 | 76°F | 55°F | 44% | 18% |
| September 15 | 74°F | 53°F | 45% | 18% |
| September 22 | 72°F | 50°F | 46% | 19% |
| September 30 | 68°F | 47°F | 47% | 20% |
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 | 78°F | 57°F | 43% | 19% | 13 h 10 min |
| September 2 | 78°F | 57°F | 43% | 19% | 13 h 10 min |
| September 3 | 78°F | 56°F | 43% | 19% | 13 h |
| September 4 | 77°F | 56°F | 44% | 18% | 13 h |
| September 5 | 77°F | 56°F | 44% | 18% | 13 h |
| September 6 | 77°F | 56°F | 44% | 18% | 13 h |
| September 7 | 77°F | 55°F | 44% | 18% | 12 h 50 min |
| September 8 | 76°F | 55°F | 44% | 18% | 12 h 50 min |
| September 9 | 76°F | 55°F | 44% | 18% | 12 h 50 min |
| September 10 | 76°F | 54°F | 44% | 18% | 12 h 50 min |
| September 11 | 75°F | 54°F | 45% | 18% | 12 h 40 min |
| September 12 | 75°F | 54°F | 45% | 18% | 12 h 40 min |
| September 13 | 75°F | 53°F | 45% | 18% | 12 h 40 min |
| September 14 | 74°F | 53°F | 45% | 18% | 12 h 40 min |
| September 15 | 74°F | 53°F | 45% | 18% | 12 h 30 min |
| September 16 | 74°F | 52°F | 45% | 18% | 12 h 30 min |
| September 17 | 73°F | 52°F | 45% | 18% | 12 h 30 min |
| September 18 | 73°F | 52°F | 46% | 19% | 12 h 20 min |
| September 19 | 73°F | 51°F | 46% | 19% | 12 h 20 min |
| September 20 | 72°F | 51°F | 46% | 19% | 12 h 20 min |
| September 21 | 72°F | 51°F | 46% | 19% | 12 h 20 min |
| September 22 | 72°F | 50°F | 46% | 19% | 12 h 10 min |
| September 23 | 71°F | 50°F | 46% | 19% | 12 h 10 min |
| September 24 | 71°F | 49°F | 46% | 19% | 12 h 10 min |
| September 25 | 70°F | 49°F | 46% | 19% | 12 h 10 min |
| September 26 | 70°F | 49°F | 47% | 20% | 12 h |
| September 27 | 70°F | 48°F | 47% | 20% | 12 h |
| September 28 | 69°F | 48°F | 47% | 20% | 12 h |
| September 29 | 69°F | 47°F | 47% | 20% | 11 h 50 min |
| September 30 | 68°F | 47°F | 47% | 20% | 11 h 50 min |
- Normal high
- 74°FSeptember average
- Normal low
- 52°FSeptember average
- Precipitation
- 4.81 inmonth total
- Days with precipitation
- 140.01 inch or more
- Daylight
- 13 h 10 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 23
- Days at 80°F or more
- 7
- Sunshine
- 77%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00054734; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Danbury in September?
On a given September day the chance of 0.01 inch or more is 45% on average, highest around September 27 (47%). In all, 4.81 in falls on 14 days of a normal September, 1 of them with an inch or more.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00054734.
What are the records for September in Danbury?
The warmest September temperature on this station's record (since 1998) is 94°F, on September 8, 2015; the coldest is 29°F, on September 29, 2000. The wettest September brought 15.86 in (1999).
The September mean against the 1991-2020 normal of 62.9°F: 2021 66.7°F (+3.8), 2022 65.5°F (+2.6), 2023 65.8°F (+2.9), 2024 64.4°F (+1.5), 2025 66.4°F (+3.5). 5 of 5 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 66.7°F | +3.8°F | 9.97 in |
| 2022 | 65.5°F | +2.6°F | – |
| 2023 | 65.8°F | +2.9°F | 13.31 in |
| 2024 | 64.4°F | +1.5°F | 1.03 in |
| 2025 | 66.4°F | +3.5°F | – |
Source: records: ACIS, station USW00054734; recent months: ACIS, station USW00054734. Records and recent months use complete months only.
How does September in Danbury compare across Connecticut?
Across the 13 places PlainClimate covers in Connecticut, September normal highs run from 69°F in Norfolk to 76°F in Hartford; Danbury's is 74°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.