Juneau weather in September: Juneau, Alaska: normal highs, lows, rain and records for September
Juneau in September has a normal high of 56°F and a normal low of 44°F, a daily mean of 50°F, falling from 60°F on the 1st to 53°F by the 30th. Measurable precipitation falls on 22 days in a normal September, 9.15 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 13°C and low of 7°C, 232 mm of precipitation in September.
- NOAA stationJuneau Airport
- Station IDUSW00025309
- Location58.36°N 134.56°W
- Elevation16 ft (5 m)
- Population31,572
- Jan 33° 24°
- Feb 36° 25°
- Mar 39° 27°
- Apr 49° 33°
- May 58° 40°
- Jun 62° 47°
- Jul 64° 50°
- Aug 63° 49°
- Sep 56° 44°
- Oct 47° 37°
- Nov 38° 29°
- Dec 35° 26°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Juneau in September?
The normal high is 56°F and the normal low 44°F, for a daily mean of 50.1°F. September is 5.9°F cooler than August and 7.9°F warmer than October. September is the 4th warmest month of the year in Juneau and the wettest. Across the month the normal high falls 7°F, from 60°F on September 1 to 53°F on September 30. From one year to the next September's mean temperature typically moves about 1.4°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 49°F and 52°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 76%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 60°F | 47°F | 71% | 52% |
| September 8 | 58°F | 45°F | 73% | 54% |
| September 15 | 56°F | 44°F | 74% | 56% |
| September 22 | 55°F | 43°F | 75% | 57% |
| September 30 | 53°F | 42°F | 76% | 57% |
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 | 60°F | 47°F | 71% | 52% | 14 h 10 min |
| September 2 | 59°F | 46°F | 71% | 53% | 14 h |
| September 3 | 59°F | 46°F | 72% | 53% | 14 h |
| September 4 | 59°F | 46°F | 72% | 53% | 13 h 50 min |
| September 5 | 59°F | 46°F | 72% | 54% | 13 h 50 min |
| September 6 | 58°F | 46°F | 72% | 54% | 13 h 40 min |
| September 7 | 58°F | 46°F | 73% | 54% | 13 h 40 min |
| September 8 | 58°F | 45°F | 73% | 54% | 13 h 30 min |
| September 9 | 58°F | 45°F | 73% | 55% | 13 h 30 min |
| September 10 | 57°F | 45°F | 73% | 55% | 13 h 20 min |
| September 11 | 57°F | 45°F | 73% | 55% | 13 h 20 min |
| September 12 | 57°F | 45°F | 74% | 55% | 13 h 10 min |
| September 13 | 57°F | 45°F | 74% | 55% | 13 h 10 min |
| September 14 | 56°F | 44°F | 74% | 56% | 13 h |
| September 15 | 56°F | 44°F | 74% | 56% | 13 h |
| September 16 | 56°F | 44°F | 74% | 56% | 12 h 50 min |
| September 17 | 56°F | 44°F | 74% | 56% | 12 h 50 min |
| September 18 | 56°F | 44°F | 74% | 56% | 12 h 40 min |
| September 19 | 55°F | 44°F | 74% | 57% | 12 h 40 min |
| September 20 | 55°F | 43°F | 75% | 57% | 12 h 30 min |
| September 21 | 55°F | 43°F | 75% | 57% | 12 h 30 min |
| September 22 | 55°F | 43°F | 75% | 57% | 12 h 20 min |
| September 23 | 54°F | 43°F | 75% | 57% | 12 h 20 min |
| September 24 | 54°F | 43°F | 75% | 57% | 12 h 10 min |
| September 25 | 54°F | 43°F | 76% | 57% | 12 h 10 min |
| September 26 | 54°F | 42°F | 76% | 57% | 12 h |
| September 27 | 53°F | 42°F | 76% | 57% | 12 h |
| September 28 | 53°F | 42°F | 76% | 57% | 11 h 50 min |
| September 29 | 53°F | 42°F | 76% | 57% | 11 h 50 min |
| September 30 | 53°F | 42°F | 76% | 57% | 11 h 40 min |
- Normal high
- 56°FSeptember average
- Normal low
- 44°FSeptember average
- Precipitation
- 9.15 inmonth total
- Days with precipitation
- 220.01 inch or more
- Nights at 32°F or colder
- 1
- Daylight
- 14 h 10 min to 11 h 40 minSeptember 1 to September 30
- Days at 70°F or more
- 1
- Sunshine
- 53%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00025309; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Juneau in September?
On a given September day the chance of 0.01 inch or more is 74% on average, highest around September 29 (76%). In all, 9.15 in falls on 22 days of a normal September, 2 of them with an inch or more.
In a normal September in Juneau, 1 nights fall to freezing.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00025309.
How humid and windy is Juneau in September?
At 3 p.m. the normal temperature is 50°F with 79% relative humidity and a dew point of 44°F; at 6 a.m. it is 44°F with 94% humidity. The wind averages 7.6 mph, most often from the east-southeast in the afternoon. A dew point under 50°F feels dry.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 44°F | 43°F | 94% | 6.4 mph | – |
| 9 a.m. | 47°F | 44°F | 90% | 7.6 mph | 6% |
| noon | 50°F | 44°F | 81% | 9.7 mph | – |
| 3 p.m. | 50°F | 44°F | 79% | 9.6 mph | 8% |
| 6 p.m. | 48°F | 44°F | 88% | 7.5 mph | – |
| 9 p.m. | 46°F | 43°F | 92% | 6.9 mph | 12% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00025309. 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 Juneau?
The warmest September temperature on Juneau's official record (since 1943) is 74°F, on September 3, 2025; the coldest is 23°F, on September 26, 1972. The wettest September brought 15.14 in (1991).
The September mean against the 1991-2020 normal of 50.1°F: 2021 50.6°F (+0.5), 2022 52.0°F (+1.9), 2023 50.9°F (+0.8), 2024 50.2°F (+0.1), 2025 52.5°F (+2.4), 2026 51.4°F (+1.3). 6 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 50.6°F | +0.5°F | 9.95 in |
| 2022 | 52.0°F | +1.9°F | 11.66 in |
| 2023 | 50.9°F | +0.8°F | 13.64 in |
| 2024 | 50.2°F | +0.1°F | 9.01 in |
| 2025 | 52.5°F | +2.4°F | 12.84 in |
| 2026 | 51.4°F | +1.3°F | 6.36 in |
Source: records: ACIS, NWS threaded record JNUthr; recent months: ACIS, station USW00025309. Records and recent months use complete months only.
How does September in Juneau compare across Alaska?
Across the 85 places PlainClimate covers in Alaska, September normal highs run from 37°F in Utqiaġvik to 60°F in Klawock; Juneau's is 56°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.