Idaho Falls weather in September: Idaho Falls, Idaho: normal highs, lows, rain and records for September
Idaho Falls in September has a normal high of 75°F and a normal low of 41°F, a daily mean of 58°F, falling from 81°F on the 1st to 68°F by the 30th. Measurable precipitation falls on 5 days in a normal September, 0.97 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 24°C and low of 5°C, 25 mm of precipitation in September.
- NOAA stationIdaho Falls Fanning Field
- Station IDUSW00024145
- Location43.52°N 112.07°W
- Elevation4,729 ft (1,441 m)
- Population69,523
- Jan 29° 12°
- Feb 34° 16°
- Mar 47° 25°
- Apr 58° 31°
- May 67° 38°
- Jun 76° 45°
- Jul 87° 49°
- Aug 86° 48°
- Sep 75° 41°
- Oct 59° 31°
- Nov 43° 22°
- Dec 30° 13°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Idaho Falls in September?
The normal high is 75°F and the normal low 41°F, for a daily mean of 57.7°F. September is 8.8°F cooler than August and 12.7°F warmer than October. September is the 4th warmest month of the year in Idaho Falls and the 4th wettest. Across the month the normal high falls 13°F, from 81°F on September 1 to 68°F on September 30. From one year to the next September's mean temperature typically moves about 2.2°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 56°F and 60°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 | 81°F | 44°F | 16% | 7% |
| September 8 | 78°F | 43°F | 17% | 8% |
| September 15 | 75°F | 41°F | 18% | 9% |
| September 22 | 72°F | 39°F | 19% | 9% |
| September 30 | 68°F | 36°F | 20% | 9% |
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 | 81°F | 44°F | 16% | 7% | 13 h 20 min |
| September 2 | 80°F | 44°F | 16% | 7% | 13 h 10 min |
| September 3 | 80°F | 44°F | 16% | 7% | 13 h 10 min |
| September 4 | 80°F | 44°F | 16% | 7% | 13 h 10 min |
| September 5 | 79°F | 43°F | 16% | 8% | 13 h |
| September 6 | 79°F | 43°F | 16% | 8% | 13 h |
| September 7 | 79°F | 43°F | 17% | 8% | 13 h |
| September 8 | 78°F | 43°F | 17% | 8% | 13 h |
| September 9 | 78°F | 42°F | 17% | 8% | 12 h 50 min |
| September 10 | 77°F | 42°F | 17% | 8% | 12 h 50 min |
| September 11 | 77°F | 42°F | 18% | 8% | 12 h 50 min |
| September 12 | 77°F | 42°F | 18% | 8% | 12 h 40 min |
| September 13 | 76°F | 41°F | 18% | 8% | 12 h 40 min |
| September 14 | 76°F | 41°F | 18% | 9% | 12 h 40 min |
| September 15 | 75°F | 41°F | 18% | 9% | 12 h 30 min |
| September 16 | 75°F | 41°F | 19% | 9% | 12 h 30 min |
| September 17 | 74°F | 40°F | 19% | 9% | 12 h 30 min |
| September 18 | 74°F | 40°F | 19% | 9% | 12 h 30 min |
| September 19 | 74°F | 40°F | 19% | 9% | 12 h 20 min |
| September 20 | 73°F | 40°F | 19% | 9% | 12 h 20 min |
| September 21 | 73°F | 39°F | 19% | 9% | 12 h 20 min |
| September 22 | 72°F | 39°F | 19% | 9% | 12 h 10 min |
| September 23 | 72°F | 39°F | 19% | 9% | 12 h 10 min |
| September 24 | 71°F | 38°F | 19% | 9% | 12 h 10 min |
| September 25 | 71°F | 38°F | 19% | 9% | 12 h 10 min |
| September 26 | 70°F | 38°F | 19% | 9% | 12 h |
| September 27 | 70°F | 37°F | 19% | 9% | 12 h |
| September 28 | 69°F | 37°F | 19% | 9% | 12 h |
| September 29 | 68°F | 37°F | 20% | 9% | 11 h 50 min |
| September 30 | 68°F | 36°F | 20% | 9% | 11 h 50 min |
- Normal high
- 75°FSeptember average
- Normal low
- 41°FSeptember average
- Precipitation
- 0.97 inmonth total
- Days with precipitation
- 50.01 inch or more
- Days at 90°F or more
- 1
- Nights at 32°F or colder
- 3
- Daylight
- 13 h 20 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 22
- Days at 80°F or more
- 11
- Sunshine
- 87%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00024145; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Idaho Falls in September?
On a given September day the chance of 0.01 inch or more is 18% on average, highest around September 30 (20%). In all, 0.97 in falls on 5 days of a normal September.
In a normal September in Idaho Falls, 1 days reach 90°F and 3 nights fall to freezing.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00024145.
What are the records for September in Idaho Falls?
The warmest September temperature on this station's record (since 1948) is 100°F, on September 3, 2022; the coldest is 18°F, on September 20, 1983. The wettest September brought 2.90 in (2017).
The September mean against the 1991-2020 normal of 57.7°F: 2021 59.2°F (+1.5), 2022 63.5°F (+5.8), 2023 60.0°F (+2.3), 2024 62.5°F (+4.8), 2025 61.4°F (+3.7), 2026 59.8°F (+2.1). 6 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 59.2°F | +1.5°F | 0.41 in |
| 2022 | 63.5°F | +5.8°F | 1.09 in |
| 2023 | 60.0°F | +2.3°F | 1.10 in |
| 2024 | 62.5°F | +4.8°F | 1.01 in |
| 2025 | 61.4°F | +3.7°F | 0.66 in |
| 2026 | 59.8°F | +2.1°F | 0.95 in |
Source: records: ACIS, station USW00024145; recent months: ACIS, station USW00024145. Records and recent months use complete months only.
How does September in Idaho 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; Idaho Falls's is 75°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.
Other months and places
- Idaho Falls in August86°F by day, 48°F at night
- Idaho Falls in October59°F by day, 31°F at night
- Idaho Falls through the yearEvery month, frost dates, records and recent years
- Idaho in SeptemberThe statewide normal and the warmest and coolest places
- Glenns Ferry: Idaho's warmest Septembernormal high 86°F