SeasonMapJuneau weather in September
United States
September in Juneau: cool, soaked, with clean air — a gamble, with 21 rainy days.
#6 of 12 months in Juneau · #1131 of 1383 destinations to visit in September · comfort 59/100 (tier D)
Updated September 2026 · climate normals from ERA5 reanalysis
Traveller notes on Juneau in September
Other months in Juneau
Juneau's forum is blunt that Southeast Alaska's weather changes hour by hour and no one can guess it days out — rain is possible in port regardless of the season. Regulars' standard packing list: proper rain gear, layers including a fleece, and a t-shirt for the occasional warm afternoon in the 60s°F.
Add your own note from Juneau's card on the map.
Juneau climate normals — September
| Daytime high | 15°C / 59°F | 🙂 cool |
|---|---|---|
| Nighttime low | 7°C / 45°F | |
| Feels like (high) | 14°C / 57°F | |
| Rainfall | 321 mm / 12.6 in | ⛈ soaked |
| Rainy days | 21 days | |
| Humidity | 85% | 💦 very humid |
| Dew point | 11°C / 51°F | |
| Sunshine | 5.7 h/day | |
| Daylight | 12.8 h | |
| Wind | 11 km/h / 7 mph | |
| Air quality (US AQI) | 27 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Juneau in September
How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.
Peak crowdsCruise season, Summer break in United States(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for Juneau's weather
Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).
Fair weatherJuneau's weather peaks June–August.
Best weatherFair weatherToughest weather
What's on in Juneau in September
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Season
Cruise season
25 Apr – 30 Sep · usuallyCrowdedShips dock nearly every day from late April to the end of September under a daily passenger cap agreed with the town. Downtown is theirs until late afternoon; the trails and the ferry terminal never are. Source ↗
- Nature
Humpback whale season
1 May – 20 Sep · usuallyHumpbacks feed in Stephens Passage and Auke Bay from May until September, and the bubble-net groups work the same water year after year. Boats out of Auke Bay find them most days in midsummer.
- Nature
Salmon run and bears
20 Jul – 15 Sep · usuallyWildlife seasonSockeye run up Steep Creek beside the Mendenhall visitor centre from late July, coho behind them into autumn, and the black bears fish it from below a public boardwalk.
- Season
Wet season
MonsoonRisk21 rainy days and about 321 mm in the month — the real kind of rainy season, not afternoon showers.
from the climate normals
Where is Juneau?
Juneau in September — FAQ
- Is September a good time to visit Juneau?
- September in Juneau: cool, soaked, with clean air — a gamble, with 21 rainy days. It ranks #6 of 12 months for Juneau on SeasonMap's comfort score (59/100).
- What is the weather like in Juneau in September?
- In September, Juneau averages a daily high of 15.1°C and a low of 7°C, with about 321.3 mm of rain over roughly 20.8 rainy days.
- What is the air quality in Juneau in September?
- Juneau has a mean US Air Quality Index of about 27 in September.