Hottest (avg)
#4 / 12
Sits around the middle of the year.
September in context
How it compares to the rest of the year in Anchorage.
Wettest (avg)
#1 / 12
The wettest month of the year.
Daylight Hours
#6 / 12
Around the yearly average.
Windiest (avg)
#7 / 12
Close to the yearly wind average.
Highest UV
#6 / 12
Near the middle of the yearly UV range.
Most Humid
#3 / 12
Humidity sits on the higher side.
Monthly climate breakdown
A detailed look at the typical climate conditions for September.
Thermal profile
Temperature
Typical daytime high
- Nighttime low
-
- Feels like (avg)
-
Light window
Sunshine
12.9 h
Average daylight
- UV index (max)
- 4
- Typical sun hours
- 06:28 - 19:19
Wet-day pattern
Rain & Snow
Typical rainfall
- Rainy days
- 19 days
- Cloud cover (avg)
- 73%
- Snowfall
-
Air feel
Humidity & Wind
82%
Average humidity
- Wind (avg)
-
- Wind (max gusts)
-
Historical daily baseline
Daily climate explorer
Pick a day to inspect the usual conditions through September in Anchorage. Based on a 30-year historical climate baseline, not a forecast.
Primary control
Select a day
Scroll to compare daily conditions. The summary updates with your selection.
Secondary context
Monthly trend
Median daytime highs across the month, with a softer low line.
Median temperatureMedian lowTypical range
Day 15 selected for September. Temperature 12.1°C.
Historical disruption baseline
Typical disruptions in September
Based on 30 years of historical data, these are the disruption patterns most likely to affect plans in September.
Cold High impact
Cold feels-like nights Measures: Cold feels-like nights (min <=5C). Observed about 51% of days (15.4 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
15.4 days / month
- Share of days
- ~51% of days
- Upper edge
- Up to ~5°C (P95)
Why this matters
Cold feels-like nights are possible on ~15 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Rain High impact
Rain disruption Measures: Likely rain disruption days. Observed about 31% of days (9.3 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
9.3 days / month
- Share of days
- ~31% of days
- Upper edge
- Up to ~27mm (P95)
Why this matters
Rain disruption risk appears on ~9 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain High impact
Washout risk Measures: Washout day risk. Observed about 31% of days (9.2 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
9.2 days / month
- Share of days
- ~31% of days
- Upper edge
- Up to ~27mm (P95)
Why this matters
Washout conditions are possible on ~9 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain High impact
Heavy rain days Measures: Heavy rain days (>=10mm). Observed about 15% of days (4.5 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
4.5 days / month
- Share of days
- ~15% of days
- Upper edge
- Up to ~32mm (P95)
Why this matters
Heavy rain is possible on ~4 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Wind High impact
Strong gusts Measures: Strong gust days (>=60 km/h). Observed about 3% of days (0.8 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.8 days / month
- Share of days
- ~3% of days
- Upper edge
- Up to ~92km/h (P95)
Why this matters
Strong gusts are possible on ~1 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Wind High impact
Stormy conditions Measures: Storm-impact proxy days. Observed about 3% of days (0.8 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.8 days / month
- Share of days
- ~3% of days
- Upper edge
- Up to ~92km/h (P95)
Why this matters
Stormy conditions are possible on ~1 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Show all disruptions (18 more)
Rain High impact
Washout run Measures: Multi-day washout runs. Observed about 2.4 days/month in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
2.4 days / month
- Share of days
- —
- Upper edge
- Up to ~41mm (P95)
Why this matters
Multi-day washout runs are possible on ~2 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain High impact
Very heavy rain Measures: Very heavy rain days (>=25mm). Observed about 2% of days (0.6 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.6 days / month
- Share of days
- ~2% of days
- Upper edge
- Up to ~53mm (P95)
Why this matters
Very heavy rain is possible on ~1 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Visibility Moderate
Fog-likely signal Measures: Fog-likely visibility proxy. Observed about 12% of days (3.5 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
3.5 days / month
- Share of days
- ~12% of days
- Upper edge
- Up to ~97% (P95)
Why this matters
Fog-likely conditions are possible on ~4 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Snow Moderate
Snow days Measures: Snow days (>=0.1mm snowfall). Observed about 6% of days (1.7 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
1.7 days / month
- Share of days
- ~6% of days
- Upper edge
- Up to ~4.7mm (P95)
Why this matters
Snowfall is possible on ~2 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Cloud Minor
Cloudy days Measures: Cloudy days (cloud cover >=60%). Observed about 74% of days (22.1 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
22.1 days / month
- Share of days
- ~74% of days
- Upper edge
- Up to ~100% (P95)
Why this matters
Cloudy skies are possible on ~22 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Rain Minor
Wet days Measures: Wet days (>=0.1mm). Observed about 71% of days (21.3 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
21.3 days / month
- Share of days
- ~71% of days
- Upper edge
- Up to ~21mm (P95)
Why this matters
Measurable rain is possible on ~21 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Humidity Minor
High humidity Measures: High humidity days (RH >=80%). Observed about 65% of days (19.6 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
19.6 days / month
- Share of days
- ~65% of days
- Upper edge
- Up to ~95% (P95)
Why this matters
High humidity is possible on ~20 days. Comfort and pace can drop quickly, so plan shorter outdoor blocks with air-conditioned backup stops.
Rain Minor
Rainy hours Measures: Rain-hours signal (>=3h rain). Observed about 62% of days (18.6 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
18.6 days / month
- Share of days
- ~62% of days
- Upper edge
- Up to ~24h (P95)
Why this matters
Several rainy hours are possible on ~19 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Cloud Minor
Mostly cloudy days Measures: Mostly cloudy days (cloud cover >=80%). Observed about 52% of days (15.7 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
15.7 days / month
- Share of days
- ~52% of days
- Upper edge
- Up to ~100% (P95)
Why this matters
Mostly cloudy skies are possible on ~16 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Rain Minor
Wet most of day Measures: Wet-most-of-day signal (>=6h rain). Observed about 52% of days (15.7 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
15.7 days / month
- Share of days
- ~52% of days
- Upper edge
- Up to ~24h (P95)
Why this matters
Wet-most-of-day conditions are possible on ~16 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Cloud Minor
Overcast days Measures: Overcast days (cloud cover >=95%). Observed about 27% of days (8.0 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
8.0 days / month
- Share of days
- ~27% of days
- Upper edge
- Up to ~100% (P95)
Why this matters
Overcast skies are possible on ~8 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Cold Minor
Cold nights Measures: Cold nights (min <=5C). Observed about 26% of days (7.8 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
7.8 days / month
- Share of days
- ~26% of days
- Upper edge
- Up to ~5°C (P95)
Why this matters
Cold nights are possible on ~8 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Cold Minor
Cold days Measures: Cold days (max <=10C). Observed about 23% of days (6.8 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
6.8 days / month
- Share of days
- ~23% of days
- Upper edge
- Up to ~10°C (P95)
Why this matters
Cold daytime conditions are possible on ~7 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Wind Minor
Gusty days Measures: Gusty days (>=40 km/h). Observed about 15% of days (4.5 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
4.5 days / month
- Share of days
- ~15% of days
- Upper edge
- Up to ~74km/h (P95)
Why this matters
Gusty conditions are possible on ~5 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Other Minor
Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data Measures: Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data. Observed about 12% of days (3.5 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
3.5 days / month
- Share of days
- ~12% of days
- Upper edge
- Up to ~97 (P95)
Why this matters
Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data is possible on ~4 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Cold Minor
Cold snap run Measures: Cold snap runs (>=3 cold days). Observed about 0.7 days/month in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.7 days / month
- Share of days
- —
- Upper edge
- Up to ~10°C (P95)
Why this matters
Cold snap runs are possible on ~1 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Cold Minor
Freezing nights Measures: Freezing nights (min <=0C). Observed about 2% of days (0.6 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.6 days / month
- Share of days
- ~2% of days
- Upper edge
- Up to ~-0°C (P95)
Why this matters
Freezing nights are possible on ~1 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Cold Minor
Hard freeze nights Measures: Hard freeze nights (min <=-2C). Observed about 1% of days (0.2 days/month) in September. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.2 days / month
- Share of days
- ~1% of days
- Upper edge
- Up to ~-3°C (P95)
Why this matters
Hard freeze conditions are possible on ~0 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Travel planning FAQ
Frequently asked questions
Quick answers to the weather questions you ask the most.
Is September a good time to visit Anchorage?
Typical September days in Anchorage reach highs of 12°C (54°F) with nights around 6°C (43°F). It usually feels cool by day and cold after dark. It is among the wetter months, so it is wise to have some indoor backup plans or flexible activities.
What are temperatures like in September?
Daytime temperatures in September typically peak near 12°C (54°F), while nights drop to around 6°C (43°F). Expect cool afternoons and cold evenings.
How much does it rain in September?
Rainfall in September averages 137 mm (5.4 in) across roughly 19 days. Overall it is a very wet time of year, so a light rain jacket and waterproof shoes are very handy.
How many hours of daylight are there in September?
You can expect about 13 hours of daylight in September. Sunrise is typically around 06:28 and sunset near 19:19. Daylight is fairly typical, with enough time for sightseeing.
How strong is the sun in September?
UV levels are moderate (around 4); sunscreen and sunglasses are still a good idea.
Is it windy in September?
In September, average wind speeds are around 6 km/h (4 mph), with gusts on the windiest days reaching about 44 km/h (27 mph). On the ground, it is it often feels breezy, especially in more exposed spots or along the coast.