Olney, United States — Weather in September 2026

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

Cfa Humid Subtropical
8.3 /10
Excellent

September is an excellent month in Olney

Climate Overview

Olney, United States in September has warm conditions, with highs averaging 25.4°C (78°F). Rain falls on about 11 days this month.

This month falls at the beginning of Autumn.

Daily highs in September gradually drop from around 27°C (81°F) at the start to 23°C (73°F) by month's end.

Rainfall is heaviest during the last third of the month, while the middle tends to be drier.

Expect around 10.0h of sunshine at the start of September, decreasing to 7.0h by the end.

The warmest days tend to fall around the 5th, averaging 27.9°C (82°F).

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

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Monthly September Averages

Temperature
25°C / 17°C
Feels Like
27°C / 18°C
Rain
11 days · 108 mm
Sunshine
8.7h / day
Humidity
74% — Humid
Wind
13 km/h
Wind Direction
NE (38°)
Gusts
33 km/h
Daylight
12.4 h
Cloud Cover
57%
Clear Sky Days
4.7
UV Index
5.2 — High
Dew Point
16°C — Humid
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 10 mm 151015202530
Rainfall

Daily Sunshine

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

Daily Wind Speed

0 4 8 12 16 20 151015202530
Wind Speed
Sun Position
Sunrise 06:50
Daylight 12.4h
Sunset 19:17

What to Expect

Daytime temperatures around 25°C (78°F) are ideal for full-day outdoor exploration.

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

Recent yearly records for September have stayed close to the long-run average.

Compare Months

January
Poor
Temp
5°C / -2°C
Feels Like
1°C / -6°C
Rain
10days (83 mm) Wet
Sun
6.2h Fair
Humidity
67% Muggy
UV
2.7 Moderate
Snow Days
5days
View Details
February
Poor
Temp
9°C / 0°C
Feels Like
5°C / -4°C
Rain
10days (89 mm) Wet
Sun
6.8h Fair
Humidity
67% Muggy
UV
3.5 Moderate
Snow Days
4days
View Details
March
Fair
Temp
13°C / 3°C
Feels Like
10°C / -1°C
Rain
10days (81 mm) Wet
Sun
8.3h Good
Humidity
64% Muggy
UV
4.9 Moderate
Snow Days
2days
View Details
April best
Good
Temp
18°C / 8°C
Feels Like
17°C / 5°C
Rain
10days (84 mm) Wet
Sun
9.1h Good
Humidity
65% Muggy
UV
5.7 High
View Details
May best
Excellent
Temp
22°C / 13°C
Feels Like
23°C / 12°C
Rain
14days (124 mm) Wet
Sun
9.3h Good
Humidity
73% Muggy
UV
6.4 High
View Details
June best
Excellent
Temp
28°C / 18°C
Feels Like
29°C / 19°C
Rain
12days (115 mm) Wet
Sun
11.4h Excellent
Humidity
69% Muggy
UV
7.3 Very High
View Details
July
Fair
Temp
31°C / 21°C
Feels Like
34°C / 24°C
Rain
14days (158 mm) Wet
Sun
11.8h Excellent
Humidity
71% Muggy
UV
7.5 Very High
View Details
August best
Good
Temp
29°C / 20°C
Feels Like
31°C / 22°C
Rain
12days (113 mm) Wet
Sun
10.6h Excellent
Humidity
74% Muggy
UV
6.9 High
View Details
September best
Excellent
Temp
25°C / 17°C
Feels Like
27°C / 18°C
Rain
11days (108 mm) Wet
Sun
8.7h Good
Humidity
74% Muggy
UV
5.2 High
View Details
October
Good
Temp
20°C / 11°C
Feels Like
19°C / 10°C
Rain
8days (79 mm) Wet
Sun
7.9h Good
Humidity
72% Muggy
UV
4.5 Moderate
View Details
November
Fair
Temp
13°C / 5°C
Feels Like
10°C / 1°C
Rain
8days (73 mm) Wet
Sun
7.3h Good
Humidity
68% Muggy
UV
3.1 Moderate
Snow Days
1days
View Details
December
Poor
Temp
7°C / 0°C
Feels Like
4°C / -4°C
Rain
9days (98 mm) Wet
Sun
5.9h Fair
Humidity
70% Muggy
UV
2.3 Moderate
Snow Days
3days
View Details
Month Temp Feels Like Rain Sun Humidity UV Status
January 5°C / -2°C 1°C / -6°C 10days (83 mm) Wet 6.2h Fair 67% Muggy 2.7 Moderate Poor View Details
February 9°C / 0°C 5°C / -4°C 10days (89 mm) Wet 6.8h Fair 67% Muggy 3.5 Moderate Poor View Details
March 13°C / 3°C 10°C / -1°C 10days (81 mm) Wet 8.3h Good 64% Muggy 4.9 Moderate Fair View Details
April best 18°C / 8°C 17°C / 5°C 10days (84 mm) Wet 9.1h Good 65% Muggy 5.7 High Good View Details
May best 22°C / 13°C 23°C / 12°C 14days (124 mm) Wet 9.3h Good 73% Muggy 6.4 High Excellent View Details
June best 28°C / 18°C 29°C / 19°C 12days (115 mm) Wet 11.4h Excellent 69% Muggy 7.3 Very High Excellent View Details
July 31°C / 21°C 34°C / 24°C 14days (158 mm) Wet 11.8h Excellent 71% Muggy 7.5 Very High Fair View Details
August best 29°C / 20°C 31°C / 22°C 12days (113 mm) Wet 10.6h Excellent 74% Muggy 6.9 High Good View Details
September best 25°C / 17°C 27°C / 18°C 11days (108 mm) Wet 8.7h Good 74% Muggy 5.2 High Excellent View Details
October 20°C / 11°C 19°C / 10°C 8days (79 mm) Wet 7.9h Good 72% Muggy 4.5 Moderate Good View Details
November 13°C / 5°C 10°C / 1°C 8days (73 mm) Wet 7.3h Good 68% Muggy 3.1 Moderate Fair View Details
December 7°C / 0°C 4°C / -4°C 9days (98 mm) Wet 5.9h Fair 70% Muggy 2.3 Moderate Poor View Details

What to Wear

Summer clothing like shorts, t-shirts, and sundresses will be comfortable. Bring a light cardigan for air-conditioned spaces.

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

Packing List

UmbrellaWaterproof jacketBreathable clothingSunscreen (SPF 30+)Sun hatSunglassesComfortable walking shoes

Frequently Asked Questions

September is typically excellent for visiting Olney, with average highs of 25°C (78°F) and around 11 rainy days. Olney, United States in September has warm conditions, with highs averaging 25.4°C (78°F). Rain falls on about 11 days t
Olney typically sees around 11 rainy days in September with 108 mm (4.3 in) of total rainfall. Pack a waterproof jacket.
Evenings in Olney during September are mild at 17°C (63°F). A light cardigan is usually enough.
With highs of 25°C (78°F) and lows of 17°C (63°F) in September, we recommend: Umbrella, Waterproof jacket, Breathable clothing, Sunscreen (SPF 30+), Sun hat. Comfortable walking shoes are essential.
Yes, September offers some of the best weather conditions in Olney with comfortable temperatures and lower chances of rain.
The average UV index in Olney during September is 5 (moderate). Sunscreen and sunglasses are recommended during midday hours.
Olney gets approximately 12 hours of daylight per day in September, with around 9 hours of sunshine.
Snow is uncommon in Olney during September based on 10-year climate averages.

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