Twin Falls weather in September: Twin Falls, Idaho: normal highs, lows, rain and records for September
Twin Falls in September has a normal high of 76°F and a normal low of 47°F, a daily mean of 62°F, falling from 82°F on the 1st to 70°F by the 30th. Measurable precipitation falls on 4 days in a normal September, 0.53 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 25°C and low of 8°C, 13 mm of precipitation in September.
- NOAA stationTwin Falls Sun Valley Regional Airport
- Station IDUSW00094178
- Location42.48°N 114.49°W
- Elevation4,151 ft (1,265 m)
- Population55,589
- Jan 37° 21°
- Feb 42° 24°
- Mar 52° 30°
- Apr 59° 34°
- May 69° 42°
- Jun 78° 49°
- Jul 88° 58°
- Aug 87° 56°
- Sep 76° 47°
- Oct 62° 36°
- Nov 47° 26°
- Dec 37° 20°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Twin Falls in September?
The normal high is 76°F and the normal low 47°F, for a daily mean of 61.8°F. September is 9.5°F cooler than August and 12.5°F warmer than October. September is the 4th warmest month of the year in Twin Falls and the 10th wettest. Across the month the normal high falls 12°F, from 82°F on September 1 to 70°F on September 30. From one year to the next September's mean temperature typically moves about 2.0°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 60°F and 64°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 16%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 82°F | 51°F | 11% | 3% |
| September 8 | 80°F | 49°F | 12% | 4% |
| September 15 | 77°F | 47°F | 14% | 5% |
| September 22 | 74°F | 45°F | 15% | 6% |
| September 30 | 70°F | 42°F | 16% | 7% |
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 | 51°F | 11% | 3% | 13 h 10 min |
| September 2 | 82°F | 51°F | 11% | 4% | 13 h 10 min |
| September 3 | 82°F | 51°F | 11% | 4% | 13 h 10 min |
| September 4 | 81°F | 51°F | 12% | 4% | 13 h |
| September 5 | 81°F | 50°F | 12% | 4% | 13 h |
| September 6 | 81°F | 50°F | 12% | 4% | 13 h |
| September 7 | 80°F | 50°F | 12% | 4% | 13 h |
| September 8 | 80°F | 49°F | 12% | 4% | 12 h 50 min |
| September 9 | 79°F | 49°F | 13% | 4% | 12 h 50 min |
| September 10 | 79°F | 49°F | 13% | 4% | 12 h 50 min |
| September 11 | 79°F | 49°F | 13% | 4% | 12 h 40 min |
| September 12 | 78°F | 48°F | 13% | 4% | 12 h 40 min |
| September 13 | 78°F | 48°F | 13% | 5% | 12 h 40 min |
| September 14 | 77°F | 48°F | 14% | 5% | 12 h 40 min |
| September 15 | 77°F | 47°F | 14% | 5% | 12 h 30 min |
| September 16 | 76°F | 47°F | 14% | 5% | 12 h 30 min |
| September 17 | 76°F | 47°F | 14% | 5% | 12 h 30 min |
| September 18 | 76°F | 46°F | 14% | 5% | 12 h 30 min |
| September 19 | 75°F | 46°F | 14% | 5% | 12 h 20 min |
| September 20 | 75°F | 46°F | 14% | 5% | 12 h 20 min |
| September 21 | 74°F | 46°F | 14% | 5% | 12 h 20 min |
| September 22 | 74°F | 45°F | 15% | 6% | 12 h 10 min |
| September 23 | 73°F | 45°F | 15% | 6% | 12 h 10 min |
| September 24 | 73°F | 45°F | 15% | 6% | 12 h 10 min |
| September 25 | 72°F | 44°F | 15% | 6% | 12 h 10 min |
| September 26 | 72°F | 44°F | 15% | 6% | 12 h |
| September 27 | 71°F | 44°F | 15% | 6% | 12 h |
| September 28 | 71°F | 43°F | 15% | 6% | 12 h |
| September 29 | 70°F | 43°F | 16% | 6% | 11 h 50 min |
| September 30 | 70°F | 42°F | 16% | 7% | 11 h 50 min |
- Normal high
- 76°FSeptember average
- Normal low
- 47°FSeptember average
- Precipitation
- 0.53 inmonth total
- Days with precipitation
- 40.01 inch or more
- Days at 90°F or more
- 3
- Nights at 32°F or colder
- 1
- Daylight
- 13 h 10 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 24
- Days at 80°F or more
- 15
- Sunshine
- 87%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00094178; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Twin Falls in September?
On a given September day the chance of 0.01 inch or more is 14% on average, highest around September 30 (16%). In all, 0.53 in falls on 4 days of a normal September.
In a normal September in Twin Falls, 3 days reach 90°F and 1 nights fall to freezing.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00094178.
What are the records for September in Twin Falls?
The warmest September temperature on this station's record (since 1997) is 102°F, on September 6, 2022; the coldest is 24°F, on September 28, 1999. The wettest September brought 2.32 in (2016).
The September mean against the 1991-2020 normal of 61.8°F: 2021 63.3°F (+1.5), 2022 66.8°F (+5.0), 2023 63.0°F (+1.2), 2024 64.5°F (+2.7), 2025 65.5°F (+3.7), 2026 62.3°F (+0.5). 6 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 63.3°F | +1.5°F | 0.29 in |
| 2022 | 66.8°F | +5.0°F | 0.20 in |
| 2023 | 63.0°F | +1.2°F | 0.51 in |
| 2024 | 64.5°F | +2.7°F | 0.23 in |
| 2025 | 65.5°F | +3.7°F | 0.49 in |
| 2026 | 62.3°F | +0.5°F | 0.23 in |
Source: records: ACIS, station USW00094178; recent months: ACIS, station USW00094178. Records and recent months use complete months only.
How does September in Twin Falls compare across Idaho?
Across the 85 places PlainClimate covers in Idaho, September normal highs run from 59°F in Mullan to 86°F in Glenns Ferry; Twin Falls's is 76°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.