Ketchikan weather in September: Ketchikan, Alaska: normal highs, lows, rain and records for September
Ketchikan in September has a normal high of 59°F and a normal low of 48°F, a daily mean of 54°F, falling from 62°F on the 1st to 56°F by the 30th. Measurable precipitation falls on 20 days in a normal September, 14.30 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 15°C and low of 9°C, 363 mm of precipitation in September.
- NOAA stationKetchikan International Airport
- Station IDUSW00025325
- Location55.36°N 131.71°W
- Elevation76 ft (23 m)
- Population8,033
- Jan 40° 32°
- Feb 41° 32°
- Mar 44° 32°
- Apr 50° 37°
- May 57° 43°
- Jun 61° 49°
- Jul 65° 53°
- Aug 65° 53°
- Sep 59° 48°
- Oct 51° 41°
- Nov 44° 36°
- Dec 40° 33°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Ketchikan in September?
The normal high is 59°F and the normal low 48°F, for a daily mean of 53.6°F. September is 5.4°F cooler than August and 7.4°F warmer than October. September is the 4th warmest month of the year in Ketchikan and the 5th wettest. Across the month the normal high falls 6°F, from 62°F on September 1 to 56°F on September 30. From one year to the next September's mean temperature typically moves about 1.6°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 52°F and 55°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 70%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 62°F | 51°F | 62% | 49% |
| September 8 | 61°F | 50°F | 64% | 51% |
| September 15 | 59°F | 49°F | 65% | 52% |
| September 22 | 58°F | 47°F | 68% | 54% |
| September 30 | 56°F | 45°F | 70% | 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 | 62°F | 51°F | 62% | 49% | 13 h 50 min |
| September 2 | 62°F | 51°F | 62% | 49% | 13 h 50 min |
| September 3 | 62°F | 51°F | 63% | 49% | 13 h 40 min |
| September 4 | 61°F | 51°F | 63% | 50% | 13 h 40 min |
| September 5 | 61°F | 50°F | 63% | 50% | 13 h 40 min |
| September 6 | 61°F | 50°F | 63% | 50% | 13 h 30 min |
| September 7 | 61°F | 50°F | 64% | 50% | 13 h 30 min |
| September 8 | 61°F | 50°F | 64% | 51% | 13 h 20 min |
| September 9 | 60°F | 50°F | 64% | 51% | 13 h 20 min |
| September 10 | 60°F | 49°F | 64% | 51% | 13 h 10 min |
| September 11 | 60°F | 49°F | 64% | 51% | 13 h 10 min |
| September 12 | 60°F | 49°F | 64% | 51% | 13 h |
| September 13 | 60°F | 49°F | 65% | 52% | 13 h |
| September 14 | 59°F | 49°F | 65% | 52% | 13 h |
| September 15 | 59°F | 49°F | 65% | 52% | 12 h 50 min |
| September 16 | 59°F | 48°F | 66% | 52% | 12 h 50 min |
| September 17 | 59°F | 48°F | 66% | 53% | 12 h 40 min |
| September 18 | 58°F | 48°F | 66% | 53% | 12 h 40 min |
| September 19 | 58°F | 48°F | 67% | 53% | 12 h 30 min |
| September 20 | 58°F | 48°F | 67% | 54% | 12 h 30 min |
| September 21 | 58°F | 47°F | 67% | 54% | 12 h 20 min |
| September 22 | 58°F | 47°F | 68% | 54% | 12 h 20 min |
| September 23 | 57°F | 47°F | 68% | 55% | 12 h 10 min |
| September 24 | 57°F | 47°F | 68% | 55% | 12 h 10 min |
| September 25 | 57°F | 46°F | 69% | 55% | 12 h 10 min |
| September 26 | 57°F | 46°F | 69% | 56% | 12 h |
| September 27 | 56°F | 46°F | 69% | 56% | 12 h |
| September 28 | 56°F | 46°F | 70% | 56% | 11 h 50 min |
| September 29 | 56°F | 46°F | 70% | 57% | 11 h 50 min |
| September 30 | 56°F | 45°F | 70% | 57% | 11 h 40 min |
- Normal high
- 59°FSeptember average
- Normal low
- 48°FSeptember average
- Precipitation
- 14.30 inmonth total
- Days with precipitation
- 200.01 inch or more
- Daylight
- 13 h 50 min to 11 h 40 minSeptember 1 to September 30
- Days at 70°F or more
- 1
- Sunshine
- 54%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00025325; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Ketchikan in September?
On a given September day the chance of 0.01 inch or more is 66% on average, highest around September 30 (70%). In all, 14.30 in falls on 20 days of a normal September, 5 of them with an inch or more.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00025325.
How humid and windy is Ketchikan in September?
At 3 p.m. the normal temperature is 53°F with 78% relative humidity and a dew point of 47°F; at 6 a.m. it is 48°F with 92% humidity. The wind averages 7.8 mph, most often from the 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. | 48°F | 46°F | 92% | 7.3 mph | – |
| 9 a.m. | 51°F | 47°F | 86% | 8.9 mph | – |
| noon | 53°F | 47°F | 78% | 10.0 mph | – |
| 3 p.m. | 53°F | 47°F | 78% | 9.4 mph | – |
| 6 p.m. | 50°F | 47°F | 87% | 7.2 mph | – |
| 9 p.m. | 49°F | 46°F | 90% | 6.7 mph | – |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00025325. 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 Ketchikan?
The warmest September temperature on this station's record (since 1910) is 80°F, on September 1, 1918; the coldest is 28°F, on September 22, 1926. The wettest September brought 28.33 in (2011).
The September mean against the 1991-2020 normal of 53.6°F: 2021 52.5°F (−1.1), 2022 55.8°F (+2.2), 2023 54.4°F (+0.8), 2024 54.0°F (+0.4), 2025 55.9°F (+2.3), 2026 54.9°F (+1.3). 5 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 52.5°F | −1.1°F | 23.68 in |
| 2022 | 55.8°F | +2.2°F | 16.97 in |
| 2023 | 54.4°F | +0.8°F | 19.69 in |
| 2024 | 54.0°F | +0.4°F | 13.70 in |
| 2025 | 55.9°F | +2.3°F | 20.11 in |
| 2026 | 54.9°F | +1.3°F | 14.23 in |
Source: records: ACIS, station USW00025325; recent months: ACIS, station USW00025325. Records and recent months use complete months only.
How does September in Ketchikan 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; Ketchikan's is 59°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.