San Francisco weather in September

In September, San Francisco sees average daytime highs of 22°C and overnight lows near 11°C, with 51 mm of rain across 5.4 wet days and about 11.8 hours of daylight. It is the 8th-warmest and 8th-wettest month of the year here.

Highs climb over the month, from about 21°C in the first days to 23°C by the end. The sky is clear or mostly clear about 55% of the time in September, and the air most often feels dry.

Daylight stretches from about 11 h 18 min at the start of September to 12 h 18 min by month's end. Set against the rest of the year, September is San Francisco's 2nd-clearest and 1st-windiest month. For the whole year in context, see San Francisco's year-round climate.

Daytime high: 22°; 8th warmest
Overnight low: 11°; 4th coldest
Rainfall: 51 mm; 5.4 wet days
Daylight: 11 h 48 min; 7:08 AM – 6:57 PM
Cloud cover: 40%; 2nd clearest
Wind: 14 km/h; 1st windiest
Solar energy: 4.97 kWh/m²
Travel score: 7.8; out of 10

San Francisco is city in Argentina.

Founded: 1886

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

← August San Francisco year-round climate October →Best places to visit in September

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 21°C in the first days to 23°C by the end.

A typical September day in San Francisco reaches about 22°C in the afternoon and slips back to 11°C overnight — a 12°C spread between the day's warmth and the night's chill. On most days the high lands between 16°C and 29°C. Set against its neighbours, September runs about 3°C warmer than August and about 3°C cooler than October.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Avg high (°C)	21	21	22	22	22	22	22	22	22	22	22	22	22	22	22	23	23	23	23	23	23	23	23	23	23	23	23	23	23	24
Avg low (°C)	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	11	11	11	11	11	11	11	11	11	11	12	12	12	12

	Avg high (°C)	Avg low (°C)
1	21	10
2	21	10
3	22	10
4	22	10
5	22	10
6	22	10
7	22	10
8	22	10
9	22	10
10	22	10
11	22	10
12	22	10
13	22	10
14	22	10
15	22	10
16	23	10
17	23	11
18	23	11
19	23	11
20	23	11
21	23	11
22	23	11
23	23	11
24	23	11
25	23	11
26	23	11
27	23	12
28	23	12
29	23	12
30	24	12

San Francisco weather by month

How September compares with the rest of the year at a glance. September is the 8th-warmest and 8th-wettest month here — the current month is highlighted below.

Month	High / Low (°C)	Rainfall (mm)	Wet days	Daylight (hours)	Travel score
Jan	30° / 19°	119	9.1	13.8	5.3
Feb	29° / 19°	115	9.1	13.1	5.8
Mar	27° / 17°	138	9.2	12.2	6.8
Apr	24° / 14°	100	8.2	11.3	7.4
May	20° / 11°	47	5.5	10.4	7.1
Jun	18° / 8°	30	4.3	10	6.6
Jul	17° / 6°	20	3.5	10.2	6.7
Aug	20° / 8°	39	3.8	10.9	7.6
Sep	22° / 11°	51	5.4	11.8	7.8
Oct	25° / 14°	116	9.6	12.8	7.2
Nov	28° / 16°	119	8.9	13.6	6.6
Dec	30° / 18°	128	9.6	14	5.5

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 55% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 13% of September, with mostly cloudy or overcast conditions the remaining 32%.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Clearer (%)	66	67	67	67	67	67	68	68	69	70	70	71	71	71	71	71	71	71	71	70	69	68	68	66	65	63	63	62	61	60
Cloudier (%)	34	33	33	33	33	33	32	32	31	30	30	29	29	29	29	29	29	29	29	30	31	32	32	34	35	37	37	38	39	40

	Clearer (%)	Cloudier (%)
1	66	34
2	67	33
3	67	33
4	67	33
5	67	33
6	67	33
7	68	32
8	68	32
9	69	31
10	70	30
11	70	30
12	71	29
13	71	29
14	71	29
15	71	29
16	71	29
17	71	29
18	71	29
19	71	29
20	70	30
21	69	31
22	68	32
23	68	32
24	66	34
25	65	35
26	63	37
27	63	37
28	62	38
29	61	39
30	60	40

Chance of precipitation in September

Any precipitation

San Francisco gets around 51 mm of rain over 5.4 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 19% and peaks near 26% on the wettest days. The odds climb toward the end of the month.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Rain chance (%)	18	18	18	18	18	18	18	18	17	17	17	16	16	16	16	16	16	16	16	17	17	18	19	20	21	22	23	24	25	26

	Rain chance (%)
1	18
2	18
3	18
4	18
5	18
6	18
7	18
8	18
9	17
10	17
11	17
12	16
13	16
14	16
15	16
16	16
17	16
18	16
19	16
20	17
21	17
22	18
23	19
24	20
25	21
26	22
27	23
28	24
29	25
30	26

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the dry band about 82% of days. It rarely turns muggy — the humid and sticky bands barely register.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Dry (%)	83	83	84	84	84	84	84	84	84	84	85	85	85	85	85	85	85	85	84	84	82	80	80	79	78	76	76	75	74	73
Comfortable (%)	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	11	11	12	13	13	14	15	16	16	17	17	17
Humid (%)	6	6	5	5	5	5	5	5	5	5	4	4	4	4	4	4	4	4	4	4	5	5	5	5	5	6	6	6	7	7
Muggy (%)	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	2	2	2	2	2	2	2	2	3

	Dry (%)	Comfortable (%)	Humid (%)	Muggy (%)
1	83	10	6	1
2	83	10	6	1
3	84	10	5	1
4	84	10	5	1
5	84	10	5	1
6	84	10	5	1
7	84	10	5	1
8	84	10	5	1
9	84	10	5	1
10	84	10	5	1
11	85	10	4	1
12	85	10	4	1
13	85	10	4	1
14	85	10	4	1
15	85	10	4	1
16	85	10	4	1
17	85	10	4	1
18	85	10	4	1
19	84	11	4	1
20	84	11	4	1
21	82	12	5	1
22	80	13	5	2
23	80	13	5	2
24	79	14	5	2
25	78	15	5	2
26	76	16	6	2
27	76	16	6	2
28	75	17	6	2
29	74	17	7	2
30	73	17	7	3

Wind in September

Winds average 14 km/h in September, the windiest month of the year.

Across September, daily wind ranges from about 14 km/h on the calmest days to 14 km/h at its breeziest. It stays fairly steady from day to day.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Wind speed (km/h)	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14	14
Feels	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze

	Wind speed (km/h)	Feels
1	14	light breeze
2	14	light breeze
3	14	light breeze
4	14	light breeze
5	14	light breeze
6	14	light breeze
7	14	light breeze
8	14	light breeze
9	14	light breeze
10	14	light breeze
11	14	light breeze
12	14	light breeze
13	14	light breeze
14	14	light breeze
15	14	light breeze
16	14	light breeze
17	14	light breeze
18	14	light breeze
19	14	light breeze
20	14	light breeze
21	14	light breeze
22	14	light breeze
23	14	light breeze
24	14	light breeze
25	14	light breeze
26	14	light breeze
27	14	light breeze
28	14	light breeze
29	14	light breeze
30	14	light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 11 h 18 min at the start of September to 12 h 18 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 60 minutes over September. Sunrise moves from 7:28 AM to 6:50 AM, and sunset from 6:48 PM to 7:06 PM.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Daylight (h)	11.3	11.4	11.4	11.4	11.5	11.5	11.5	11.6	11.6	11.6	11.6	11.7	11.7	11.7	11.8	11.8	11.8	11.9	11.9	11.9	12.0	12.0	12.0	12.1	12.1	12.1	12.2	12.2	12.2	12.3
Sunrise (AM)	7:28	7:27	7:26	7:24	7:23	7:22	7:20	7:19	7:18	7:16	7:15	7:14	7:12	7:11	7:10	7:08	7:07	7:06	7:04	7:03	7:02	7:00	6:59	6:57	6:56	6:55	6:53	6:52	6:51	6:50
Sunset (PM)	6:48	6:48	6:49	6:50	6:50	6:51	6:52	6:52	6:53	6:53	6:54	6:55	6:55	6:56	6:56	6:57	6:58	6:58	6:59	6:59	7:00	7:01	7:01	7:02	7:03	7:03	7:04	7:04	7:05	7:06

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	11.3	7:28	6:48
2	11.4	7:27	6:48
3	11.4	7:26	6:49
4	11.4	7:24	6:50
5	11.5	7:23	6:50
6	11.5	7:22	6:51
7	11.5	7:20	6:52
8	11.6	7:19	6:52
9	11.6	7:18	6:53
10	11.6	7:16	6:53
11	11.6	7:15	6:54
12	11.7	7:14	6:55
13	11.7	7:12	6:55
14	11.7	7:11	6:56
15	11.8	7:10	6:56
16	11.8	7:08	6:57
17	11.8	7:07	6:58
18	11.9	7:06	6:58
19	11.9	7:04	6:59
20	11.9	7:03	6:59
21	12.0	7:02	7:00
22	12.0	7:00	7:01
23	12.0	6:59	7:01
24	12.1	6:57	7:02
25	12.1	6:56	7:03
26	12.1	6:55	7:03
27	12.2	6:53	7:04
28	12.2	6:52	7:04
29	12.2	6:51	7:05
30	12.3	6:50	7:06

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.97 kWh/m².

For context, solar energy here swings from a low near 2.55 kWh/m² to a high of 7.19 kWh/m² in December across the year — September's 4.97 kWh/m² falls in the middle.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Solar energy (kWh/m²)	4.4	4.4	4.5	4.5	4.5	4.6	4.6	4.7	4.7	4.8	4.8	4.9	4.9	5.0	5.0	5.1	5.1	5.1	5.2	5.2	5.2	5.2	5.2	5.3	5.3	5.3	5.3	5.3	5.3	5.3
Level	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright

	Solar energy (kWh/m²)	Level
1	4.4	Bright
2	4.4	Bright
3	4.5	Bright
4	4.5	Bright
5	4.5	Bright
6	4.6	Bright
7	4.6	Bright
8	4.7	Bright
9	4.7	Bright
10	4.8	Bright
11	4.8	Bright
12	4.9	Bright
13	4.9	Bright
14	5.0	Bright
15	5.0	Bright
16	5.1	Bright
17	5.1	Bright
18	5.1	Bright
19	5.2	Bright
20	5.2	Bright
21	5.2	Bright
22	5.2	Bright
23	5.2	Bright
24	5.3	Bright
25	5.3	Bright
26	5.3	Bright
27	5.3	Bright
28	5.3	Bright
29	5.3	Bright
30	5.3	Bright

Planning a trip in September

Is September a good time to visit San Francisco?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

7.8

Sightseeing

1st-best month of the year

5.6

Beach & pool

8th-best month of the year

September is one of the better times to visit San Francisco for general sightseeing.

What to pack for San Francisco in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, San Francisco sees daytime highs around 22°C and nights near 11°C. Worth packing: light clothes and sun protection. About 5 days see rain.

light clothessun protection

UV index in San Francisco in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in San Francisco peaks around January 17 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 21 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
UV index (midday)	14	13	11	7	4	3	3	5	7	10	11	13
Level	Extreme	Extreme	Extreme	High	Moderate	Moderate	Moderate	Moderate	High	Very high	Extreme	Extreme

	UV index (midday)	Level
Jan	14	Extreme
Feb	13	Extreme
Mar	11	Extreme
Apr	7	High
May	4	Moderate
Jun	3	Moderate
Jul	3	Moderate
Aug	5	Moderate
Sep	7	High
Oct	10	Very high
Nov	11	Extreme
Dec	13	Extreme

Location & terrain

Where is San Francisco?

San Francisco sits at 31.4°S, 62.1°W, 120 m above sea level, in Argentina. The nearest listed city is San Jorge, 57 km away.

Topography around San Francisco

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of San Francisco.

Within 3 km, the terrain around San Francisco has only modest variations in elevation — a maximum elevation change of 13 m around an average of 114 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 24 m; within 80 km, only modest variations in elevation — a maximum elevation change of 103 m.

The land around San Francisco is covered by artificial surfaces (50%) and cropland (30%) within 3 km, cropland (94%) within 16 km, and cropland (88%) within 80 km.

3 km

13 m

artificial surfaces 50%

16 km

24 m

cropland 94%

80 km

103 m

cropland 88%

treesgrasslandcroplandartificial surfaceswater

← August San Francisco year-round climate October →Best places to visit in September

September weather nearby: San Jorge 57 km · Rafaela 60 km · Sunchales 73 km · Las Varillas 78 km · Morteros 80 km · Arroyito 92 km · Gálvez 106 km · Esperanza 109 km

Argentina travel facts

Travel advisory: Level 1; Exercise Normal Precautions
Power plugs: Type C / I; 220 V · 50 Hz
Prices: ≈ 46% of US; price level, 2025
GDP per capita: $14,898; 2025
Happiness: 6.4 / 10; World Happiness, 2025
Homicide rate: 4.5; per 100k, 2023
Road deaths: 14.1; per 100k/yr, 2019
Income group: Upper middle; World Bank
English: High; EF EPI 575
Religion

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for San Francisco (-31.425°, -62.084°, elevation 120 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).

	Avg high (°C)	Avg low (°C)
1	21	10
2	21	10
3	22	10
4	22	10
5	22	10
6	22	10
7	22	10
8	22	10
9	22	10
10	22	10
11	22	10
12	22	10
13	22	10
14	22	10
15	22	10
16	23	10
17	23	11
18	23	11
19	23	11
20	23	11
21	23	11
22	23	11
23	23	11
24	23	11
25	23	11
26	23	11
27	23	12
28	23	12
29	23	12
30	24	12

	Clearer (%)	Cloudier (%)
1	66	34
2	67	33
3	67	33
4	67	33
5	67	33
6	67	33
7	68	32
8	68	32
9	69	31
10	70	30
11	70	30
12	71	29
13	71	29
14	71	29
15	71	29
16	71	29
17	71	29
18	71	29
19	71	29
20	70	30
21	69	31
22	68	32
23	68	32
24	66	34
25	65	35
26	63	37
27	63	37
28	62	38
29	61	39
30	60	40

	Rain chance (%)
1	18
2	18
3	18
4	18
5	18
6	18
7	18
8	18
9	17
10	17
11	17
12	16
13	16
14	16
15	16
16	16
17	16
18	16
19	16
20	17
21	17
22	18
23	19
24	20
25	21
26	22
27	23
28	24
29	25
30	26

	Dry (%)	Comfortable (%)	Humid (%)	Muggy (%)
1	83	10	6	1
2	83	10	6	1
3	84	10	5	1
4	84	10	5	1
5	84	10	5	1
6	84	10	5	1
7	84	10	5	1
8	84	10	5	1
9	84	10	5	1
10	84	10	5	1
11	85	10	4	1
12	85	10	4	1
13	85	10	4	1
14	85	10	4	1
15	85	10	4	1
16	85	10	4	1
17	85	10	4	1
18	85	10	4	1
19	84	11	4	1
20	84	11	4	1
21	82	12	5	1
22	80	13	5	2
23	80	13	5	2
24	79	14	5	2
25	78	15	5	2
26	76	16	6	2
27	76	16	6	2
28	75	17	6	2
29	74	17	7	2
30	73	17	7	3

	Avg high (°C)	Avg low (°C)
1	21	10
2	21	10
3	22	10
4	22	10
5	22	10
6	22	10
7	22	10
8	22	10
9	22	10
10	22	10
11	22	10
12	22	10
13	22	10
14	22	10
15	22	10
16	23	10
17	23	11
18	23	11
19	23	11
20	23	11
21	23	11
22	23	11
23	23	11
24	23	11
25	23	11
26	23	11
27	23	12
28	23	12
29	23	12
30	24	12

	Clearer (%)	Cloudier (%)
1	66	34
2	67	33
3	67	33
4	67	33
5	67	33
6	67	33
7	68	32
8	68	32
9	69	31
10	70	30
11	70	30
12	71	29
13	71	29
14	71	29
15	71	29
16	71	29
17	71	29
18	71	29
19	71	29
20	70	30
21	69	31
22	68	32
23	68	32
24	66	34
25	65	35
26	63	37
27	63	37
28	62	38
29	61	39
30	60	40

	Rain chance (%)
1	18
2	18
3	18
4	18
5	18
6	18
7	18
8	18
9	17
10	17
11	17
12	16
13	16
14	16
15	16
16	16
17	16
18	16
19	16
20	17
21	17
22	18
23	19
24	20
25	21
26	22
27	23
28	24
29	25
30	26

	Dry (%)	Comfortable (%)	Humid (%)	Muggy (%)
1	83	10	6	1
2	83	10	6	1
3	84	10	5	1
4	84	10	5	1
5	84	10	5	1
6	84	10	5	1
7	84	10	5	1
8	84	10	5	1
9	84	10	5	1
10	84	10	5	1
11	85	10	4	1
12	85	10	4	1
13	85	10	4	1
14	85	10	4	1
15	85	10	4	1
16	85	10	4	1
17	85	10	4	1
18	85	10	4	1
19	84	11	4	1
20	84	11	4	1
21	82	12	5	1
22	80	13	5	2
23	80	13	5	2
24	79	14	5	2
25	78	15	5	2
26	76	16	6	2
27	76	16	6	2
28	75	17	6	2
29	74	17	7	2
30	73	17	7	3

	Avg high (°C)	Avg low (°C)
1	21	10
2	21	10
3	22	10
4	22	10
5	22	10
6	22	10
7	22	10
8	22	10
9	22	10
10	22	10
11	22	10
12	22	10
13	22	10
14	22	10
15	22	10
16	23	10
17	23	11
18	23	11
19	23	11
20	23	11
21	23	11
22	23	11
23	23	11
24	23	11
25	23	11
26	23	11
27	23	12
28	23	12
29	23	12
30	24	12

	Clearer (%)	Cloudier (%)
1	66	34
2	67	33
3	67	33
4	67	33
5	67	33
6	67	33
7	68	32
8	68	32
9	69	31
10	70	30
11	70	30
12	71	29
13	71	29
14	71	29
15	71	29
16	71	29
17	71	29
18	71	29
19	71	29
20	70	30
21	69	31
22	68	32
23	68	32
24	66	34
25	65	35
26	63	37
27	63	37
28	62	38
29	61	39
30	60	40

	Rain chance (%)
1	18
2	18
3	18
4	18
5	18
6	18
7	18
8	18
9	17
10	17
11	17
12	16
13	16
14	16
15	16
16	16
17	16
18	16
19	16
20	17
21	17
22	18
23	19
24	20
25	21
26	22
27	23
28	24
29	25
30	26

	Dry (%)	Comfortable (%)	Humid (%)	Muggy (%)
1	83	10	6	1
2	83	10	6	1
3	84	10	5	1
4	84	10	5	1
5	84	10	5	1
6	84	10	5	1
7	84	10	5	1
8	84	10	5	1
9	84	10	5	1
10	84	10	5	1
11	85	10	4	1
12	85	10	4	1
13	85	10	4	1
14	85	10	4	1
15	85	10	4	1
16	85	10	4	1
17	85	10	4	1
18	85	10	4	1
19	84	11	4	1
20	84	11	4	1
21	82	12	5	1
22	80	13	5	2
23	80	13	5	2
24	79	14	5	2
25	78	15	5	2
26	76	16	6	2
27	76	16	6	2
28	75	17	6	2
29	74	17	7	2
30	73	17	7	3