Richardson weather in September: Richardson, Texas: normal highs, lows, rain and records for September
Richardson in September has a normal high of 87°F and a normal low of 67°F, a daily mean of 77°F, falling from 91°F on the 1st to 83°F by the 30th. Measurable precipitation falls on 6 days in a normal September, 3.30 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 31°C and low of 19°C, 84 mm of precipitation in September.
- NOAA stationRichardson
- Station IDUSC00417588
- Location33.00°N 96.74°W
- Elevation678 ft (207 m)
- From the center3 miles
- Population118,221
- Jan 56° 36°
- Feb 60° 40°
- Mar 69° 48°
- Apr 75° 55°
- May 83° 64°
- Jun 90° 71°
- Jul 94° 75°
- Aug 95° 75°
- Sep 87° 67°
- Oct 78° 56°
- Nov 66° 46°
- Dec 57° 38°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Richardson in September?
The normal high is 87°F and the normal low 67°F, for a daily mean of 77.2°F. September is 7.5°F cooler than August and 10.4°F warmer than October. September is the 4th warmest month of the year in Richardson and the 8th wettest. Across the month the normal high falls 8°F, from 91°F on September 1 to 83°F on September 30. From one year to the next September's mean temperature typically moves about 2.5°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 75°F and 80°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 20%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 91°F | 71°F | 20% | 14% |
| September 8 | 89°F | 69°F | 20% | 14% |
| September 15 | 87°F | 67°F | 20% | 14% |
| September 22 | 86°F | 65°F | 20% | 14% |
| September 30 | 83°F | 62°F | 20% | 14% |
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 | 91°F | 71°F | 20% | 14% | 12 h 50 min |
| September 2 | 91°F | 71°F | 20% | 14% | 12 h 50 min |
| September 3 | 91°F | 71°F | 20% | 14% | 12 h 50 min |
| September 4 | 90°F | 71°F | 20% | 14% | 12 h 50 min |
| September 5 | 90°F | 70°F | 20% | 14% | 12 h 50 min |
| September 6 | 90°F | 70°F | 20% | 14% | 12 h 40 min |
| September 7 | 90°F | 70°F | 20% | 14% | 12 h 40 min |
| September 8 | 89°F | 69°F | 20% | 14% | 12 h 40 min |
| September 9 | 89°F | 69°F | 20% | 14% | 12 h 40 min |
| September 10 | 89°F | 69°F | 20% | 14% | 12 h 40 min |
| September 11 | 89°F | 69°F | 20% | 14% | 12 h 30 min |
| September 12 | 88°F | 68°F | 20% | 14% | 12 h 30 min |
| September 13 | 88°F | 68°F | 20% | 14% | 12 h 30 min |
| September 14 | 88°F | 68°F | 20% | 14% | 12 h 30 min |
| September 15 | 87°F | 67°F | 20% | 14% | 12 h 30 min |
| September 16 | 87°F | 67°F | 20% | 14% | 12 h 20 min |
| September 17 | 87°F | 67°F | 20% | 14% | 12 h 20 min |
| September 18 | 87°F | 67°F | 20% | 14% | 12 h 20 min |
| September 19 | 86°F | 66°F | 20% | 14% | 12 h 20 min |
| September 20 | 86°F | 66°F | 20% | 14% | 12 h 20 min |
| September 21 | 86°F | 66°F | 20% | 14% | 12 h 10 min |
| September 22 | 86°F | 65°F | 20% | 14% | 12 h 10 min |
| September 23 | 85°F | 65°F | 20% | 14% | 12 h 10 min |
| September 24 | 85°F | 65°F | 20% | 14% | 12 h 10 min |
| September 25 | 85°F | 64°F | 20% | 14% | 12 h 10 min |
| September 26 | 85°F | 64°F | 20% | 14% | 12 h |
| September 27 | 84°F | 64°F | 20% | 14% | 12 h |
| September 28 | 84°F | 63°F | 20% | 14% | 12 h |
| September 29 | 84°F | 63°F | 20% | 14% | 12 h |
| September 30 | 83°F | 62°F | 20% | 14% | 12 h |
- Normal high
- 87°FSeptember average
- Normal low
- 67°FSeptember average
- Precipitation
- 3.30 inmonth total
- Days with precipitation
- 60.01 inch or more
- Days at 90°F or more
- 13
- Daylight
- 12 h 50 min to 12 hSeptember 1 to September 30
- Days at 70°F or more
- 30
- Days at 80°F or more
- 26
- Sunshine
- 84%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USC00417588; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Richardson in September?
On a given September day the chance of 0.01 inch or more is 20% on average, highest around September 1 (20%). In all, 3.30 in falls on 6 days of a normal September, 1 of them with an inch or more.
In a normal September in Richardson, 13 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USC00417588.
What are the records for September in Richardson?
The September mean against the 1991-2020 normal of 77.2°F: 2021 79.4°F (+2.2), 2022 78.8°F (+1.6), 2023 82.7°F (+5.5), 2024 80.0°F (+2.8), 2025 80.5°F (+3.3). 5 of 5 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 79.4°F | +2.2°F | 0.31 in |
| 2022 | 78.8°F | +1.6°F | 4.01 in |
| 2023 | 82.7°F | +5.5°F | 1.57 in |
| 2024 | 80.0°F | +2.8°F | 2.31 in |
| 2025 | 80.5°F | +3.3°F | 1.01 in |
Source: recent months: ACIS, station USC00417588. Records and recent months use complete months only.
How does September in Richardson compare across Texas?
Across the 321 places PlainClimate covers in Texas, September normal highs run from 81°F in Hart to 95°F in Presidio; Richardson's is 87°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.