West Allis, United States — Weather in September 2026

Monthly climate averages for West Allis, United States. Based on 10-year ERA5 reanalysis data.

Dfa Hot-Summer Continental
8.9 /10
Excellent

September is an excellent month in West Allis

Climate Overview

West Allis, United States in September has warm conditions, with highs averaging 22.5°C (73°F). Rain falls on about 10 days this month.

This month falls at the beginning of Autumn.

Daily highs in September gradually drop from around 24°C (75°F) at the start to 20°C (68°F) by month's end.

September sees fairly even rainfall, totalling about 85 mm across the month.

Expect around 10.0h of sunshine at the start of September, decreasing to 8.8h by the end.

The warmest days tend to fall around the 1th, averaging 24.1°C (75°F).

Compared to August, this month is about 3°C cooler with 1 more rainy days. Temperatures begin dropping heading into October.

LIVE Current Weather Local Time
LIVE Air Quality

Monthly September Averages

Temperature
23°C / 16°C
Feels Like
23°C / 15°C
Rain
10 days · 85 mm
Sunshine
9.4h / day
Humidity
73% — Humid
Wind
20 km/h
Wind Direction
SSE (162°)
Gusts
37 km/h
Daylight
12.5 h
Cloud Cover
49%
Clear Sky Days
7.1
UV Index
5.2 — High
Dew Point
14°C — Comfortable
Moon Phase
Waxing Crescent · 11%

Climate Charts

Daily averages based on historical data (2016–2025)

Daily Temperature

32°C 28°C 24°C 20°C 16°C 12°C 8°C 151015202530
High Low

Daily Precipitation

0 mm 2 mm 4 mm 6 mm 8 mm 151015202530
Rainfall

Daily Sunshine

0h 3h 6h 9h 12h 151015202530
Sunshine

Daily Wind Speed

0 6 12 18 24 30 151015202530
Wind Speed
Sun Position
Sunrise 06:32
Daylight 12.5h
Sunset 19:02

What to Expect

Daytime temperatures around 23°C (73°F) are ideal for full-day outdoor exploration.

Rain usually comes in shorter passing showers rather than all-day rain.

1 of the last 5 yearly records were warmer than this month's long-run average.

Compare Months

January
Poor
Temp
-1°C / -7°C
Feels Like
-6°C / -13°C
Rain
8days (57 mm) Wet
Sun
5.2h Fair
Humidity
74% Muggy
UV
2.1 Moderate
Snow Days
11days
View Details
February
Poor
Temp
1°C / -6°C
Feels Like
-4°C / -12°C
Rain
7days (46 mm) Good
Sun
6.9h Fair
Humidity
70% Muggy
UV
3.2 Moderate
Snow Days
9days
View Details
March
Poor
Temp
6°C / -1°C
Feels Like
2°C / -6°C
Rain
10days (85 mm) Wet
Sun
7.8h Good
Humidity
69% Muggy
UV
4.3 Moderate
Snow Days
7days
View Details
April
Poor
Temp
11°C / 3°C
Feels Like
8°C / -1°C
Rain
13days (101 mm) Wet
Sun
9h Good
Humidity
69% Muggy
UV
5.3 High
Snow Days
4days
View Details
May
Good
Temp
17°C / 9°C
Feels Like
15°C / 6°C
Rain
12days (103 mm) Wet
Sun
10.2h Excellent
Humidity
73% Muggy
UV
6.4 High
View Details
June best
Excellent
Temp
23°C / 15°C
Feels Like
24°C / 14°C
Rain
11days (83 mm) Wet
Sun
11.8h Excellent
Humidity
72% Muggy
UV
6.9 High
View Details
July best
Excellent
Temp
26°C / 19°C
Feels Like
28°C / 20°C
Rain
10days (84 mm) Wet
Sun
12.4h Excellent
Humidity
74% Muggy
UV
7 High
View Details
August best
Excellent
Temp
26°C / 19°C
Feels Like
27°C / 19°C
Rain
9days (76 mm) Wet
Sun
11.3h Excellent
Humidity
73% Muggy
UV
6.3 High
View Details
September best
Excellent
Temp
23°C / 16°C
Feels Like
23°C / 15°C
Rain
10days (85 mm) Wet
Sun
9.4h Good
Humidity
73% Muggy
UV
5.2 High
View Details
October
Fair
Temp
16°C / 9°C
Feels Like
13°C / 6°C
Rain
11days (93 mm) Wet
Sun
7.2h Good
Humidity
69% Muggy
UV
3.6 Moderate
Snow Days
1days
View Details
November
Poor
Temp
8°C / 2°C
Feels Like
4°C / -3°C
Rain
8days (53 mm) Wet
Sun
6.1h Fair
Humidity
69% Muggy
UV
2.3 Moderate
Snow Days
4days
View Details
December
Poor
Temp
2°C / -4°C
Feels Like
-3°C / -9°C
Rain
8days (52 mm) Wet
Sun
4.9h Fair
Humidity
72% Muggy
UV
1.8 Low
Snow Days
9days
View Details
Month Temp Feels Like Rain Sun Humidity UV Status
January -1°C / -7°C -6°C / -13°C 8days (57 mm) Wet 5.2h Fair 74% Muggy 2.1 Moderate Poor View Details
February 1°C / -6°C -4°C / -12°C 7days (46 mm) Good 6.9h Fair 70% Muggy 3.2 Moderate Poor View Details
March 6°C / -1°C 2°C / -6°C 10days (85 mm) Wet 7.8h Good 69% Muggy 4.3 Moderate Poor View Details
April 11°C / 3°C 8°C / -1°C 13days (101 mm) Wet 9h Good 69% Muggy 5.3 High Poor View Details
May 17°C / 9°C 15°C / 6°C 12days (103 mm) Wet 10.2h Excellent 73% Muggy 6.4 High Good View Details
June best 23°C / 15°C 24°C / 14°C 11days (83 mm) Wet 11.8h Excellent 72% Muggy 6.9 High Excellent View Details
July best 26°C / 19°C 28°C / 20°C 10days (84 mm) Wet 12.4h Excellent 74% Muggy 7 High Excellent View Details
August best 26°C / 19°C 27°C / 19°C 9days (76 mm) Wet 11.3h Excellent 73% Muggy 6.3 High Excellent View Details
September best 23°C / 16°C 23°C / 15°C 10days (85 mm) Wet 9.4h Good 73% Muggy 5.2 High Excellent View Details
October 16°C / 9°C 13°C / 6°C 11days (93 mm) Wet 7.2h Good 69% Muggy 3.6 Moderate Fair View Details
November 8°C / 2°C 4°C / -3°C 8days (53 mm) Wet 6.1h Fair 69% Muggy 2.3 Moderate Poor View Details
December 2°C / -4°C -3°C / -9°C 8days (52 mm) Wet 4.9h Fair 72% Muggy 1.8 Low Poor View Details

What to Wear

Dress in layers — a mix of long sleeves, light sweaters, and a versatile jacket works best for changeable conditions.

A waterproof jacket or compact umbrella is recommended for occasional showers.

Packing List

UmbrellaWaterproof jacketSunscreen (SPF 30+)SunglassesComfortable walking shoes

Frequently Asked Questions

September is typically excellent for visiting West Allis, with average highs of 23°C (73°F) and around 10 rainy days. West Allis, United States in September has warm conditions, with highs averaging 22.5°C (73°F). Rain falls on about 10 d
West Allis typically sees around 10 rainy days in September with 85 mm (3.3 in) of total rainfall. An umbrella should suffice.
Evenings in West Allis during September are mild at 16°C (61°F). A light cardigan is usually enough.
With highs of 23°C (73°F) and lows of 16°C (61°F) in September, we recommend: Umbrella, Waterproof jacket, Sunscreen (SPF 30+), Sunglasses, Comfortable walking shoes. Comfortable walking shoes are essential.
Yes, September offers some of the best weather conditions in West Allis with comfortable temperatures and lower chances of rain.
The average UV index in West Allis during September is 5 (moderate). Sunscreen and sunglasses are recommended during midday hours.
West Allis gets approximately 13 hours of daylight per day in September, with around 9 hours of sunshine.
Snow is uncommon in West Allis during September based on 10-year climate averages.

Last updated: