California, United States — Weather in September 2026

Climate Overview

California, United States in September has warm conditions, with highs averaging 25.3°C (78°F). Rain falls on about 10 days this month. Sea temperature reaches 25.2°C (77°F).

This month falls at the beginning of Autumn.

Daily highs in September gradually drop from around 27°C (80°F) at the start to 24°C (74°F) by month's end.

September sees fairly even rainfall, totalling about 117 mm across the month.

Expect around 10.4h of sunshine at the start of September, decreasing to 6.9h by the end.

The warmest days tend to fall around the 5th, averaging 27.4°C (81°F).

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

Monthly September Averages

Temperature

25°C / 20°C

Feels Like

27°C / 21°C

Rain

10 days · 118 mm

Sunshine

8.9h / day

Humidity

76% — Humid

Wind

19 km/h

Wind Direction

ENE (65°)

Gusts

34 km/h

Daylight

12.4 h

Cloud Cover

55%

Clear Sky Days

5.1

UV Index

5.4 — High

Sea Temperature

25°C

Dew Point

18°C — Humid

Moon Phase

Waxing Crescent · 11%

Climate Charts

Daily averages based on historical data (2016–2025)

Daily Temperature

High Low

Daily Precipitation

Rainfall

Daily Sunshine

Sunshine

Daily Wind Speed

Wind Speed

Sun Position

Sunrise 06:48

Daylight 12.4h

Sunset 19:14

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

Month	Temp	Feels Like	Rain	Sun	Humidity	UV	Status	Details
January	7°C / 1°C	3°C / -4°C	10days (96 mm) Wet	6.4h Fair	70% Muggy	2.7 Moderate	Poor	View Details
February	9°C / 3°C	6°C / -2°C	11days (112 mm) Wet	6.7h Fair	71% Muggy	3.6 Moderate	Poor	View Details
March	13°C / 6°C	10°C / 1°C	10days (98 mm) Wet	8.3h Good	68% Muggy	5.1 High	Fair	View Details
April	18°C / 11°C	17°C / 7°C	10days (90 mm) Wet	9.5h Good	68% Muggy	5.9 High	Good	View Details
May best	22°C / 16°C	23°C / 15°C	12days (118 mm) Wet	9.7h Good	75% Muggy	6.6 High	Excellent	View Details
June best	27°C / 21°C	30°C / 22°C	10days (87 mm) Wet	11.8h Excellent	73% Muggy	7.4 Very High	Excellent	View Details
July	30°C / 24°C	34°C / 27°C	12days (127 mm) Wet	11.9h Excellent	75% Muggy	7.5 Very High	Fair	View Details
August	28°C / 23°C	32°C / 26°C	11days (106 mm) Wet	10.7h Excellent	75% Muggy	6.8 High	Good	View Details
September best	25°C / 20°C	27°C / 21°C	10days (118 mm) Wet	8.9h Good	76% Humid	5.4 High	Excellent	View Details
October best	20°C / 15°C	20°C / 13°C	8days (100 mm) Wet	7.9h Good	73% Muggy	4.6 Moderate	Excellent	View Details
November	14°C / 8°C	12°C / 4°C	8days (75 mm) Wet	7.4h Good	69% Muggy	3.3 Moderate	Fair	View Details
December	9°C / 3°C	6°C / -1°C	11days (105 mm) Wet	6h Fair	72% Muggy	2.4 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

Expand all

Is September a good time to visit California?

September is typically excellent for visiting California, with average highs of 25°C (78°F) and around 10 rainy days. California, United States in September has warm conditions, with highs averaging 25.3°C (78°F). Rain falls on about 10 d

Does it rain a lot in California in September?

California typically sees around 10 rainy days in September with 118 mm (4.6 in) of total rainfall. An umbrella should suffice.

Does it get cold at night in California in September?

Nights stay pleasantly warm in California during September, around 20°C (69°F). Light evening wear is sufficient.

What should I pack for California in September?

With highs of 25°C (78°F) and lows of 20°C (69°F) in September, we recommend: Umbrella, Waterproof jacket, Breathable clothing, Sunscreen (SPF 30+), Sun hat. Comfortable walking shoes are essential.

Is September among the best months weather-wise in California?

Yes, September offers some of the best weather conditions in California with comfortable temperatures and lower chances of rain.

What is the UV index in California in September?

The average UV index in California during September is 5 (moderate). Sunscreen and sunglasses are recommended during midday hours.

How many hours of daylight are there in California in September?

California gets approximately 12 hours of daylight per day in September, with around 9 hours of sunshine.

Does it snow in California in September?

Snow is uncommon in California during September based on 10-year climate averages.

Last updated: