San Francisco Weather

September 2026

Historical data
Average Temperature
20.8 °C
High
/
14.3 °C
Low
6.7mm
Precipitation
33.6°C
Peak Temp
11.9°C
Low Temp
30
Days Count

Temperature Trends

Daily high, low, and average

Weather Extremes

Most notable conditions during this period

Period High

33.6°C
Wednesday, September 9

Compare with historical weather

Load the same period from the previous 15 years.

Weather Insights

Key findings from analysis for selected period

Highly Variable Temperatures

Worth noting

Temperature swings from 11.9°C to 33.6°C (21.7°C range).

Variable Temperatures

Worth noting

Large temperature swings (21.7°C range) for a month.

Dry Weather

Notable

Very little rainfall (7mm total).

⚠️

1 Exceptional Weather Event

Info

The most extreme day in this period:

Sep 9 Heat

Hottest day: 33.6°C

1 High Heat Index Day

Info

1 day where humidity amplified heat sensation (36.9°C heat index). 33.6°C temperature felt like 36.9°C due to 48% humidity.

High Humidity Levels

Info

Average humidity of 77% indicates persistently moist air conditions. Heat sensation amplified during warm periods (20.8°C average temperature).

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Data Source

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