Grand Junction weather in September: Grand Junction, Colorado: normal highs, lows, rain and records for September
Grand Junction in September has a normal high of 82°F and a normal low of 53°F, a daily mean of 67°F, falling from 87°F on the 1st to 75°F by the 30th. Measurable precipitation falls on 7 days in a normal September, 1.19 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 28°C and low of 11°C, 30 mm of precipitation in September.
- NOAA stationGrand Junction Walker Field
- Station IDUSW00023066
- Location39.13°N 108.54°W
- Elevation4,858 ft (1,481 m)
- From the center3 miles
- Population70,554
- Jan 38° 17°
- Feb 46° 24°
- Mar 58° 32°
- Apr 66° 38°
- May 77° 47°
- Jun 89° 57°
- Jul 95° 64°
- Aug 91° 62°
- Sep 82° 53°
- Oct 67° 40°
- Nov 52° 28°
- Dec 39° 18°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Grand Junction in September?
The normal high is 82°F and the normal low 53°F, for a daily mean of 67.1°F. September is 9.2°F cooler than August and 13.9°F warmer than October. September is the 4th warmest month of the year in Grand Junction and the wettest. Across the month the normal high falls 12°F, from 87°F on September 1 to 75°F on September 30. From one year to the next September's mean temperature typically moves about 2.3°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 65°F and 69°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 23%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 87°F | 58°F | 22% | 11% |
| September 8 | 85°F | 56°F | 23% | 12% |
| September 15 | 82°F | 53°F | 22% | 12% |
| September 22 | 79°F | 50°F | 21% | 12% |
| September 30 | 75°F | 47°F | 20% | 11% |
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 | 87°F | 58°F | 22% | 11% | 13 h 10 min |
| September 2 | 87°F | 57°F | 22% | 11% | 13 h |
| September 3 | 87°F | 57°F | 22% | 11% | 13 h |
| September 4 | 86°F | 57°F | 22% | 11% | 13 h |
| September 5 | 86°F | 57°F | 22% | 11% | 13 h |
| September 6 | 86°F | 56°F | 22% | 11% | 12 h 50 min |
| September 7 | 85°F | 56°F | 22% | 12% | 12 h 50 min |
| September 8 | 85°F | 56°F | 23% | 12% | 12 h 50 min |
| September 9 | 85°F | 55°F | 23% | 12% | 12 h 50 min |
| September 10 | 84°F | 55°F | 23% | 12% | 12 h 40 min |
| September 11 | 84°F | 54°F | 23% | 12% | 12 h 40 min |
| September 12 | 84°F | 54°F | 23% | 12% | 12 h 40 min |
| September 13 | 83°F | 54°F | 23% | 12% | 12 h 40 min |
| September 14 | 83°F | 53°F | 23% | 12% | 12 h 30 min |
| September 15 | 82°F | 53°F | 22% | 12% | 12 h 30 min |
| September 16 | 82°F | 53°F | 22% | 12% | 12 h 30 min |
| September 17 | 81°F | 52°F | 22% | 12% | 12 h 30 min |
| September 18 | 81°F | 52°F | 22% | 12% | 12 h 20 min |
| September 19 | 80°F | 51°F | 22% | 12% | 12 h 20 min |
| September 20 | 80°F | 51°F | 22% | 12% | 12 h 20 min |
| September 21 | 80°F | 51°F | 21% | 12% | 12 h 20 min |
| September 22 | 79°F | 50°F | 21% | 12% | 12 h 10 min |
| September 23 | 79°F | 50°F | 21% | 12% | 12 h 10 min |
| September 24 | 78°F | 49°F | 21% | 12% | 12 h 10 min |
| September 25 | 78°F | 49°F | 21% | 11% | 12 h 10 min |
| September 26 | 77°F | 48°F | 21% | 11% | 12 h |
| September 27 | 77°F | 48°F | 21% | 11% | 12 h |
| September 28 | 76°F | 47°F | 20% | 11% | 12 h |
| September 29 | 76°F | 47°F | 20% | 11% | 12 h |
| September 30 | 75°F | 47°F | 20% | 11% | 11 h 50 min |
- Normal high
- 82°FSeptember average
- Normal low
- 53°FSeptember average
- Precipitation
- 1.19 inmonth total
- Days with precipitation
- 70.01 inch or more
- Days at 90°F or more
- 4
- Daylight
- 13 h 10 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 27
- Days at 80°F or more
- 20
- Sunshine
- 86%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00023066; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Grand Junction in September?
On a given September day the chance of 0.01 inch or more is 22% on average, highest around September 9 (23%). In all, 1.19 in falls on 7 days of a normal September.
In a normal September in Grand Junction, 4 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00023066.
How humid and windy is Grand Junction in September?
At 3 p.m. the normal temperature is 73°F with 23% relative humidity and a dew point of 33°F; at 6 a.m. it is 50°F with 54% humidity. The wind averages 8.1 mph, most often from the west in the afternoon. A dew point under 50°F feels dry.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 50°F | 34°F | 54% | 8.3 mph | 80% |
| 9 a.m. | 60°F | 36°F | 40% | 9.5 mph | 80% |
| noon | 69°F | 35°F | 29% | 7.1 mph | 77% |
| 3 p.m. | 73°F | 33°F | 23% | 9.5 mph | 80% |
| 6 p.m. | 68°F | 34°F | 28% | 6.9 mph | 79% |
| 9 p.m. | 58°F | 34°F | 39% | 6.7 mph | 81% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00023066. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for September in Grand Junction?
The warmest September temperature on Grand Junction's official record (since 1893) is 102°F, on September 6, 2022; the coldest is 28°F, on September 27, 1908. The wettest September brought 3.78 in (1896); the snowiest, 3.1 inches (1965).
The September mean against the 1991-2020 normal of 67.1°F: 2021 69.0°F (+1.9), 2022 71.2°F (+4.1), 2023 69.8°F (+2.7), 2024 73.4°F (+6.3), 2025 68.5°F (+1.4), 2026 70.6°F (+3.5). 6 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 69.0°F | +1.9°F | 1.89 in |
| 2022 | 71.2°F | +4.1°F | 2.29 in |
| 2023 | 69.8°F | +2.7°F | 0.07 in |
| 2024 | 73.4°F | +6.3°F | 0.27 in |
| 2025 | 68.5°F | +1.4°F | 0.97 in |
| 2026 | 70.6°F | +3.5°F | 1.58 in |
Source: records: ACIS, NWS threaded record GJTthr; recent months: ACIS, station USW00023066. Records and recent months use complete months only.
How does September in Grand Junction compare across Colorado?
Across the 125 places PlainClimate covers in Colorado, September normal highs run from 62°F in Leadville to 86°F in Lamar; Grand Junction's is 82°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.
Other months and places
- Grand Junction in August91°F by day, 62°F at night
- Grand Junction in October67°F by day, 40°F at night
- Grand Junction through the yearEvery month, frost dates, records and recent years
- Colorado in SeptemberThe statewide normal and the warmest and coolest places
- Lamar: Colorado's warmest Septembernormal high 86°F