Walla Walla weather in September: Walla Walla, Washington: normal highs, lows, rain and records for September
Walla Walla in September has a normal high of 79°F and a normal low of 54°F, a daily mean of 66°F, falling from 84°F on the 1st to 72°F by the 30th. Measurable precipitation falls on 4 days in a normal September, 0.64 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 26°C and low of 12°C, 16 mm of precipitation in September.
- NOAA stationWalla Walla Regional Airport
- Station IDUSW00024160
- Location46.09°N 118.29°W
- Elevation1,166 ft (355 m)
- Population33,901
- Jan 42° 31°
- Feb 47° 33°
- Mar 56° 38°
- Apr 63° 43°
- May 71° 49°
- Jun 79° 55°
- Jul 90° 62°
- Aug 89° 62°
- Sep 79° 54°
- Oct 63° 44°
- Nov 49° 36°
- Dec 41° 30°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Walla Walla in September?
The normal high is 79°F and the normal low 54°F, for a daily mean of 66.2°F. September is 9.0°F cooler than August and 12.5°F warmer than October. September is the 4th warmest month of the year in Walla Walla and the 10th wettest. Across the month the normal high falls 12°F, from 84°F on September 1 to 72°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 64°F and 68°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 19%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 84°F | 58°F | 10% | 4% |
| September 8 | 82°F | 56°F | 11% | 5% |
| September 15 | 79°F | 54°F | 13% | 6% |
| September 22 | 76°F | 52°F | 16% | 7% |
| September 30 | 72°F | 50°F | 19% | 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 | 84°F | 58°F | 10% | 4% | 13 h 20 min |
| September 2 | 84°F | 58°F | 10% | 4% | 13 h 20 min |
| September 3 | 83°F | 57°F | 10% | 4% | 13 h 20 min |
| September 4 | 83°F | 57°F | 10% | 4% | 13 h 10 min |
| September 5 | 83°F | 57°F | 10% | 4% | 13 h 10 min |
| September 6 | 82°F | 57°F | 11% | 4% | 13 h 10 min |
| September 7 | 82°F | 56°F | 11% | 5% | 13 h |
| September 8 | 82°F | 56°F | 11% | 5% | 13 h |
| September 9 | 81°F | 56°F | 11% | 5% | 13 h |
| September 10 | 81°F | 56°F | 12% | 5% | 12 h 50 min |
| September 11 | 81°F | 55°F | 12% | 5% | 12 h 50 min |
| September 12 | 80°F | 55°F | 12% | 5% | 12 h 50 min |
| September 13 | 80°F | 55°F | 12% | 5% | 12 h 40 min |
| September 14 | 79°F | 54°F | 13% | 6% | 12 h 40 min |
| September 15 | 79°F | 54°F | 13% | 6% | 12 h 40 min |
| September 16 | 79°F | 54°F | 14% | 6% | 12 h 30 min |
| September 17 | 78°F | 54°F | 14% | 6% | 12 h 30 min |
| September 18 | 78°F | 53°F | 14% | 7% | 12 h 30 min |
| September 19 | 77°F | 53°F | 15% | 7% | 12 h 20 min |
| September 20 | 77°F | 53°F | 15% | 7% | 12 h 20 min |
| September 21 | 77°F | 53°F | 16% | 7% | 12 h 20 min |
| September 22 | 76°F | 52°F | 16% | 7% | 12 h 10 min |
| September 23 | 76°F | 52°F | 16% | 8% | 12 h 10 min |
| September 24 | 75°F | 52°F | 17% | 8% | 12 h 10 min |
| September 25 | 75°F | 51°F | 17% | 8% | 12 h 10 min |
| September 26 | 74°F | 51°F | 18% | 8% | 12 h |
| September 27 | 74°F | 51°F | 18% | 8% | 12 h |
| September 28 | 73°F | 50°F | 18% | 9% | 12 h |
| September 29 | 73°F | 50°F | 19% | 9% | 11 h 50 min |
| September 30 | 72°F | 50°F | 19% | 9% | 11 h 50 min |
- Normal high
- 79°FSeptember average
- Normal low
- 54°FSeptember average
- Precipitation
- 0.64 inmonth total
- Days with precipitation
- 40.01 inch or more
- Days at 90°F or more
- 3
- Daylight
- 13 h 20 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 26
- Days at 80°F or more
- 14
- Sunshine
- 87%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00024160; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Walla Walla in September?
On a given September day the chance of 0.01 inch or more is 14% on average, highest around September 30 (19%). In all, 0.64 in falls on 4 days of a normal September.
In a normal September in Walla Walla, 3 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00024160.
How humid and windy is Walla Walla in September?
At 3 p.m. the normal temperature is 72°F with 32% relative humidity and a dew point of 40°F; at 6 a.m. it is 52°F with 64% humidity. The wind averages 7.4 mph, most often from the southwest in the afternoon. A dew point under 50°F feels dry.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 52°F | 40°F | 64% | 6.8 mph | 73% |
| 9 a.m. | 61°F | 41°F | 48% | 7.7 mph | 72% |
| noon | 68°F | 41°F | 37% | 7.9 mph | 73% |
| 3 p.m. | 72°F | 40°F | 32% | 7.8 mph | 72% |
| 6 p.m. | 65°F | 42°F | 44% | 6.4 mph | 74% |
| 9 p.m. | 58°F | 42°F | 54% | 8.3 mph | 77% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00024160. 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 Walla Walla?
The warmest September temperature on this station's record (since 1949) is 104°F, on September 2, 1950; the coldest is 32°F, on September 17, 1965. The wettest September brought 2.85 in (1959).
The September mean against the 1991-2020 normal of 66.2°F: 2021 65.4°F (−0.8), 2022 67.9°F (+1.7), 2023 64.9°F (−1.3), 2024 69.1°F (+2.9), 2025 71.4°F (+5.2), 2026 63.8°F (−2.4). 3 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 65.4°F | −0.8°F | 0.76 in |
| 2022 | 67.9°F | +1.7°F | 0.18 in |
| 2023 | 64.9°F | −1.3°F | 0.66 in |
| 2024 | 69.1°F | +2.9°F | 0.60 in |
| 2025 | 71.4°F | +5.2°F | 0.56 in |
| 2026 | 63.8°F | −2.4°F | 0.97 in |
Source: records: ACIS, station USW00024160; recent months: ACIS, station USW00024160. Records and recent months use complete months only.
How does September in Walla Walla compare across Washington?
Across the 96 places PlainClimate covers in Washington, September normal highs run from 66°F in Coupeville to 81°F in Pasco; Walla Walla's is 79°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.
Other months and places
- Walla Walla in August89°F by day, 62°F at night
- Walla Walla in October63°F by day, 44°F at night
- Walla Walla through the yearEvery month, frost dates, records and recent years
- Washington in SeptemberThe statewide normal and the warmest and coolest places
- Pasco: Washington's warmest Septembernormal high 81°F