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San Luis Obispo County (San Luis Obispo)
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United States weather

Weather in San Luis Obispo County, California for September 2025

Your guide to San Luis Obispo County weather in September - trends and predictions

    Official Weather Alert ⚠️

  • Special Weather Statement - See hour by hour.

    • Temperatures

  • Until now, September 2025 in San Luis Obispo County is slightly cooler than the historical average by -0.7 °F.

  • Expect cooler weather in the next days in San Luis Obispo County with the forecast suggesting a temperature of 24.6 °F, lower than the historical average.

  • In general, the average temperature in San Luis Obispo County at the beginning of September is 27.7 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 23.1 °F by the end of September.

    • Rain 🌧️

  • Precipitation in San Luis Obispo County during September is a rare event, with an average of fewer than 2 rainy days.

    • More

  • New! Chat with our AI weatherman - it’s amazing and free.

Average dry days
30
Dry days
Average rainy days
0
Rainy days
Average snowy days
0
Snow days
Average temperatures
25°/13°
Temperatures
Average wind speed
13 km/h
Avg max wind
Average humidity
63 %
Avg humidity

San Luis Obispo County Weather September

Move between months or click on a day
August
October
Sun.Mon.Tue.Wed.Thu.Fri.Sat.
1
Sunny
28°
2
Sunny
26°
3
Sunny
28°
4
Sunny
26°
5
Sunny
29°
6
Sunny
28°
7
Sunny
29°
8
Sunny
27°
9
Sunny
25°
10
Sunny
22°
11
Sunny
23°
12
Sunny
25°
13
Sunny
23°
14
Sunny
27°
15
Patchy rain possible
24°
16
Partly cloudy
23°
17
Weather Alert Partly cloudy
35°
18
Weather Alert Patchy rain possible
22°
19
Weather Alert Partly cloudy
26°
20
Partly cloudy
25°
21
Sunny
26°
22
Sunny
26°
23
Patchy rain possible
22°
24
Sunny
22°
25
Partly cloudy
21°
26
Partly cloudy
22°
27
Patchy rain possible
20°
28
Sunny
24°
29
Sunny
26°
30
Sunny
27°

Temperatures trend during September in San Luis Obispo County

See the weather trend as well as the moving average line

September weather in San Luis Obispo County day by day

Click on a date for more information
August October
Date Weather Temperatures Rain UV More
Sept. 1 Sunny
Sunny
 28° /14° 0 mm 7
Sept. 2 Sunny
Sunny
 26° /14° 0 mm 7
Sept. 3 Sunny
Sunny
 28° /15° 0 mm 7
Sept. 4 Sunny
Sunny
 26° /14° 0 mm 7
Sept. 5 Sunny
Sunny
 29° /16° 0 mm 8
Sept. 6 Sunny
Sunny
 28° /16° 0 mm 7
Sept. 7 Sunny
Sunny
 29° /16° 0 mm 8
Sept. 8 Sunny
Sunny
 27° /15° 0 mm 7
Sept. 9 Sunny
Sunny
 25° /13° 0 mm 6
Sept. 10 Sunny
Sunny
 22° /11° 0 mm 6
Sept. 11 Sunny
Sunny
 23° /11° 0 mm 6
Sept. 12 Sunny
Sunny
 25° /11° 0 mm 6
Sept. 13 Sunny
Sunny
 23° /11° 0 mm 6
Sept. 14 Sunny
Sunny
 27° /12° 0 mm 7
Sept. 15 Patchy rain possible
Patchy rain possible
 24° /13° 0 mm 6
Sept. 16 Partly cloudy
Partly cloudy
 23° /13° 0 mm 6
Sept. 17 Partly cloudy
Partly cloudy
 35° /18° 0 mm 1.5
Sept. 18 Patchy rain possible
Patchy rain possible
 22° /17° 0.4 mm 0.5
Sept. 19 Partly cloudy
Partly cloudy
 26° /15° 0 mm 1.6
Sept. 20 Partly cloudy
Partly cloudy
 25° /13° 0 mm 1.8
Sept. 21 Sunny
Sunny
 26° /15° 0 mm 1.8
Sept. 22 Sunny
Sunny
 26° /16° 0 mm 0
Sept. 23 Patchy rain possible
Patchy rain possible
 22° /16° 1.4 mm 4
Sept. 24 Sunny
Sunny
 22° /13° 0 mm 5
Sept. 25 Partly cloudy
Partly cloudy
 21° /13° 0 mm 5
Sept. 26 Partly cloudy
Partly cloudy
 22° /14° 0 mm 5
Sept. 27 Patchy rain possible
Patchy rain possible
 20° /14° 0.2 mm 4
Sept. 28 Sunny
Sunny
 24° /14° 0 mm 5
Sept. 29 Sunny
Sunny
 26° /14° 0 mm 5
Sept. 30 Sunny
Sunny
 27° /15° 0 mm 6
Next
Important Notice
Our weather forecast for San Luis Obispo County in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the San Luis Obispo County forecast closer to your planned date for the most up-to-date weather information.
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San Luis Obispo County in September - FAQ

What are the expected maximum and minimum temperatures in San Luis Obispo County during September?
Enjoy moderate daytime temperatures of up to 25° and cooler nights around 13°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in San Luis Obispo County during September?
Rainfall in San Luis Obispo County during September is rare to nonexistent, with the total expected rainfall being less than 10 mm and approximately 0 days seeing any precipitation. Planning without the concern for rain is generally straightforward during this very dry period.
What are the typical wind conditions in San Luis Obispo County during September?
The average wind speed in San Luis Obispo County during September is 13 km/h, suggesting breezy to windy conditions, depending on your activities.

September rainfall patterns in San Luis Obispo County

Explore the daily rainfall trends and prepare for San Luis Obispo Countys September weather 💧

UV exposure in San Luis Obispo County during September

Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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Location coordinates Where is San Luis Obispo County?

Get accurate weather forecasts for San Luis Obispo County, located at latitude 35.283 and longitude -120.66. Stay updated with localized weather information tailored for San Luis Obispo County.

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