San Diego weather in September

In September, San Diego sees average daytime highs of 30°C and overnight lows near 22°C, with 471 mm of rain across 29.4 wet days and about 12.1 hours of daylight. It is the 5th-warmest and 3rd-wettest month of the year here.

Day-to-day highs hold fairly steady near 30°C through the month. The sky is clear or mostly clear about 1% of the time in September, and the air most often feels muggy.

Daylight stretches from about 12 h 12 min at the start of September to 11 h 54 min by month's end. Set against the rest of the year, September is San Diego's 10th-clearest and 12th-windiest month. For the whole year in context, see San Diego's year-round climate.

Daytime high: 30°; 5th warmest
Overnight low: 22°; 8th coldest
Rainfall: 471 mm; 29.4 wet days
Daylight: 12 h 06 min; 5:45 AM – 5:49 PM
Cloud cover: 90%; 10th clearest
Wind: 4 km/h; 12th windiest
Solar energy: 4.68 kWh/m²
Travel score: 2.6; out of 10

← August San Diego 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

Day-to-day highs hold fairly steady near 30°C through the month.

A typical September day in San Diego reaches about 30°C in the afternoon and slips back to 22°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 27°C and 32°C. Set against its neighbours, September runs on par with August and about 1°C warmer 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)	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	29	29	29	29	29	29	29	29	29	29	29	29
Avg low (°C)	22	22	22	22	22	22	22	22	22	22	22	22	22	22	22	22	22	22	22	22	22	22	22	22	22	22	22	22	22	22

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

How September really feels in San Diego

Once humidity and wind are folded in, September averages 0 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C

heat index over the day's high

Days feeling ≤ 0°C

wind chill below the day's low

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

San Diego weather by month

How September compares with the rest of the year at a glance. September is the 5th-warmest and 3rd-wettest month here — the current month is highlighted below.

Month	High / Low (°C)	Rainfall (mm)	Wet days	Daylight (hours)	Travel score
Jan	30° / 20°	53	7	11.5	5.8
Feb	30° / 21°	74	8	11.7	5.5
Mar	30° / 21°	189	14.5	11.9	4.7
Apr	29° / 22°	410	24.2	12.2	3.4
May	29° / 23°	569	30.6	12.5	2.7
Jun	30° / 22°	385	28.2	12.6	2.8
Jul	30° / 22°	260	27.3	12.5	2.7
Aug	30° / 22°	379	28.8	12.3	2.6
Sep	30° / 22°	471	29.4	12.1	2.6
Oct	29° / 22°	508	30	11.8	2.9
Nov	28° / 21°	355	26.3	11.5	3.5
Dec	29° / 21°	130	16	11.4	4.8

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 1% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 4% of September, with mostly cloudy or overcast conditions the remaining 95%.

	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 (%)	5	6	6	6	6	6	6	6	6	6	6	6	5	5	5	4	4	4	4	4	4	4	4	4	4	4	4	4	5	5
Cloudier (%)	95	94	94	94	94	94	94	94	94	94	94	94	95	95	95	96	96	96	96	96	96	96	96	96	96	96	96	96	95	95

	Clearer (%)	Cloudier (%)
1	5	95
2	6	94
3	6	94
4	6	94
5	6	94
6	6	94
7	6	94
8	6	94
9	6	94
10	6	94
11	6	94
12	6	94
13	5	95
14	5	95
15	5	95
16	4	96
17	4	96
18	4	96
19	4	96
20	4	96
21	4	96
22	4	96
23	4	96
24	4	96
25	4	96
26	4	96
27	4	96
28	4	96
29	5	95
30	5	95

Chance of precipitation in September

Any precipitation

San Diego gets around 471 mm of rain over 29.4 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 98% and peaks near 99% on the wettest days.

	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 (%)	97	97	97	97	97	97	97	98	98	98	98	98	98	98	98	98	99	99	99	99	99	99	99	98	98	98	98	98	98	98

	Rain chance (%)
1	97
2	97
3	97
4	97
5	97
6	97
7	97
8	98
9	98
10	98
11	98
12	98
13	98
14	98
15	98
16	98
17	99
18	99
19	99
20	99
21	99
22	99
23	99
24	98
25	98
26	98
27	98
28	98
29	98
30	98

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the muggy band about 78% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

	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
Humid (%)	1	1	1	1	1	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Muggy (%)	86	86	86	85	85	84	85	84	83	82	81	80	79	78	77	77	76	75	74	74	74	73	73	73	73	73	74	74	74	74
Oppressive (%)	13	13	13	14	14	15	15	16	17	18	19	20	21	22	23	23	24	25	26	26	26	27	27	27	27	27	26	26	26	26

	Humid (%)	Muggy (%)	Oppressive (%)
1	1	86	13
2	1	86	13
3	1	86	13
4	1	85	14
5	1	85	14
6	1	84	15
7	0	85	15
8	0	84	16
9	0	83	17
10	0	82	18
11	0	81	19
12	0	80	20
13	0	79	21
14	0	78	22
15	0	77	23
16	0	77	23
17	0	76	24
18	0	75	25
19	0	74	26
20	0	74	26
21	0	74	26
22	0	73	27
23	0	73	27
24	0	73	27
25	0	73	27
26	0	73	27
27	0	74	26
28	0	74	26
29	0	74	26
30	0	74	26

Wind in September

Winds average 4 km/h in September, the calmest month.

Across September, daily wind ranges from about 4 km/h on the calmest days to 4 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)	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4
Feels	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm

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

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 12 min at the start of September to 11 h 54 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 18 minutes over September. Sunrise moves from 5:46 AM to 5:44 AM, and sunset from 5:58 PM to 5:40 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)	12.2	12.2	12.2	12.2	12.2	12.2	12.1	12.1	12.1	12.1	12.1	12.1	12.1	12.1	12.1	12.1	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	12.0	11.9	11.9	11.9	11.9
Sunrise (AM)	5:46	5:46	5:46	5:46	5:46	5:46	5:46	5:46	5:46	5:46	5:46	5:46	5:46	5:46	5:45	5:45	5:45	5:45	5:45	5:45	5:45	5:45	5:45	5:45	5:45	5:45	5:45	5:45	5:44	5:44
Sunset (PM)	5:58	5:58	5:57	5:57	5:56	5:55	5:55	5:54	5:53	5:53	5:52	5:51	5:51	5:50	5:49	5:49	5:48	5:47	5:47	5:46	5:45	5:45	5:44	5:43	5:43	5:42	5:42	5:41	5:40	5:40

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	12.2	5:46	5:58
2	12.2	5:46	5:58
3	12.2	5:46	5:57
4	12.2	5:46	5:57
5	12.2	5:46	5:56
6	12.2	5:46	5:55
7	12.1	5:46	5:55
8	12.1	5:46	5:54
9	12.1	5:46	5:53
10	12.1	5:46	5:53
11	12.1	5:46	5:52
12	12.1	5:46	5:51
13	12.1	5:46	5:51
14	12.1	5:46	5:50
15	12.1	5:45	5:49
16	12.1	5:45	5:49
17	12.0	5:45	5:48
18	12.0	5:45	5:47
19	12.0	5:45	5:47
20	12.0	5:45	5:46
21	12.0	5:45	5:45
22	12.0	5:45	5:45
23	12.0	5:45	5:44
24	12.0	5:45	5:43
25	12.0	5:45	5:43
26	12.0	5:45	5:42
27	11.9	5:45	5:42
28	11.9	5:45	5:41
29	11.9	5:44	5:40
30	11.9	5:44	5:40

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.68 kWh/m².

For context, solar energy here swings from a low near 4.37 kWh/m² to a high of 5.87 kWh/m² in February across the year — September's 4.68 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)	4.8	4.8	4.8	4.8	4.8	4.8	4.8	4.8	4.8	4.7	4.7	4.7	4.7	4.7	4.7	4.7	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6	4.6
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	4.8	Bright
2	4.8	Bright
3	4.8	Bright
4	4.8	Bright
5	4.8	Bright
6	4.8	Bright
7	4.8	Bright
8	4.8	Bright
9	4.8	Bright
10	4.7	Bright
11	4.7	Bright
12	4.7	Bright
13	4.7	Bright
14	4.7	Bright
15	4.7	Bright
16	4.7	Bright
17	4.6	Bright
18	4.6	Bright
19	4.6	Bright
20	4.6	Bright
21	4.6	Bright
22	4.6	Bright
23	4.6	Bright
24	4.6	Bright
25	4.6	Bright
26	4.6	Bright
27	4.6	Bright
28	4.6	Bright
29	4.6	Bright
30	4.6	Bright

Planning a trip in September

Is September a good time to visit San Diego?

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

2.6

Sightseeing

11th-best month of the year

3.6

Beach & pool

12th-best month of the year

September is a weaker month for outdoor sightseeing in San Diego.

What to pack for San Diego in September

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

In September, San Diego sees daytime highs around 30°C and nights near 22°C. Pack light clothes and rain gear. Worth having: sun protection. About 29 days see rain.

light clothesrain gearsun protection

UV index in San Diego in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 13 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in San Diego peaks around April 12 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 12 at about 10 (very high).

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)	11	13	13	14	12	13	12	13	13	12	10	10
Level	Extreme	Extreme	Extreme	Extreme	Extreme	Extreme	Extreme	Extreme	Extreme	Extreme	Extreme	Very high

	UV index (midday)	Level
Jan	11	Extreme
Feb	13	Extreme
Mar	13	Extreme
Apr	14	Extreme
May	12	Extreme
Jun	13	Extreme
Jul	12	Extreme
Aug	13	Extreme
Sep	13	Extreme
Oct	12	Extreme
Nov	10	Extreme
Dec	10	Very high

Air quality in San Diego in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.

Air quality in San Diego is worst in March — around 34 µg/m³ PM2.5 (moderate), about 3.6× the cleanest month (December, 9 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
PM2.5 (µg/m³)	11	19	34	23	20	21	21	17	13	12	10	9
Level	Good	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Good	Good	Good

	PM2.5 (µg/m³)	Level
Jan	11	Good
Feb	19	Moderate
Mar	34	Moderate
Apr	23	Moderate
May	20	Moderate
Jun	21	Moderate
Jul	21	Moderate
Aug	17	Moderate
Sep	13	Moderate
Oct	12	Good
Nov	10	Good
Dec	9	Good

Location & terrain

Where is San Diego?

San Diego sits at 10.3°N, 73.2°W, 180 m above sea level, in Colombia. The nearest listed city is Valledupar, 17 km away.

Topography around San Diego

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

Within 3 km, the terrain around San Diego has only modest variations in elevation — a maximum elevation change of 215 m around an average of 170 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,747 m; within 80 km, extreme variations in elevation — a maximum elevation change of 5,632 m.

The land around San Diego is covered by grassland (49%) and trees (40%) within 3 km, trees (55%) and grassland (38%) within 16 km, and trees (64%) and grassland (31%) within 80 km.

3 km

215 m

grassland 49%

16 km

1,747 m

trees 55%

80 km

5,632 m

trees 64%

treesshrubsgrasslandcroplandartificial surfacesbare terrain

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

September weather nearby: Valledupar 17 km · Agustín Codazzi 34 km · Villanueva 38 km · San Juan del Cesar 52 km · Becerril 71 km · Fonseca 71 km · Machiques 75 km · Barrancas 81 km

Colombia travel facts

Travel advisory: Level 3; Reconsider Travel
Power plugs: Type A / B; 120 / 240 V · 60 Hz
Prices: ≈ 38% of US; price level, 2025
GDP per capita: $8,562; 2025
Happiness: 6.0 / 10; World Happiness, 2025
Safe drinking water: 74%; of population, 2024
Homicide rate: 24.9; per 100k, 2023
Road deaths: 15.4; per 100k/yr, 2019
Income group: Upper middle; World Bank
English: Low; EF EPI 480
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 Diego (10.3338°, -73.1805°, elevation 180 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. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. 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	30	22
2	30	22
3	30	22
4	30	22
5	30	22
6	30	22
7	30	22
8	30	22
9	30	22
10	30	22
11	30	22
12	30	22
13	30	22
14	30	22
15	30	22
16	30	22
17	30	22
18	30	22
19	29	22
20	29	22
21	29	22
22	29	22
23	29	22
24	29	22
25	29	22
26	29	22
27	29	22
28	29	22
29	29	22
30	29	22

	Clearer (%)	Cloudier (%)
1	5	95
2	6	94
3	6	94
4	6	94
5	6	94
6	6	94
7	6	94
8	6	94
9	6	94
10	6	94
11	6	94
12	6	94
13	5	95
14	5	95
15	5	95
16	4	96
17	4	96
18	4	96
19	4	96
20	4	96
21	4	96
22	4	96
23	4	96
24	4	96
25	4	96
26	4	96
27	4	96
28	4	96
29	5	95
30	5	95

	Rain chance (%)
1	97
2	97
3	97
4	97
5	97
6	97
7	97
8	98
9	98
10	98
11	98
12	98
13	98
14	98
15	98
16	98
17	99
18	99
19	99
20	99
21	99
22	99
23	99
24	98
25	98
26	98
27	98
28	98
29	98
30	98

	Humid (%)	Muggy (%)	Oppressive (%)
1	1	86	13
2	1	86	13
3	1	86	13
4	1	85	14
5	1	85	14
6	1	84	15
7	0	85	15
8	0	84	16
9	0	83	17
10	0	82	18
11	0	81	19
12	0	80	20
13	0	79	21
14	0	78	22
15	0	77	23
16	0	77	23
17	0	76	24
18	0	75	25
19	0	74	26
20	0	74	26
21	0	74	26
22	0	73	27
23	0	73	27
24	0	73	27
25	0	73	27
26	0	73	27
27	0	74	26
28	0	74	26
29	0	74	26
30	0	74	26

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

	Clearer (%)	Cloudier (%)
1	5	95
2	6	94
3	6	94
4	6	94
5	6	94
6	6	94
7	6	94
8	6	94
9	6	94
10	6	94
11	6	94
12	6	94
13	5	95
14	5	95
15	5	95
16	4	96
17	4	96
18	4	96
19	4	96
20	4	96
21	4	96
22	4	96
23	4	96
24	4	96
25	4	96
26	4	96
27	4	96
28	4	96
29	5	95
30	5	95

	Rain chance (%)
1	97
2	97
3	97
4	97
5	97
6	97
7	97
8	98
9	98
10	98
11	98
12	98
13	98
14	98
15	98
16	98
17	99
18	99
19	99
20	99
21	99
22	99
23	99
24	98
25	98
26	98
27	98
28	98
29	98
30	98

	Humid (%)	Muggy (%)	Oppressive (%)
1	1	86	13
2	1	86	13
3	1	86	13
4	1	85	14
5	1	85	14
6	1	84	15
7	0	85	15
8	0	84	16
9	0	83	17
10	0	82	18
11	0	81	19
12	0	80	20
13	0	79	21
14	0	78	22
15	0	77	23
16	0	77	23
17	0	76	24
18	0	75	25
19	0	74	26
20	0	74	26
21	0	74	26
22	0	73	27
23	0	73	27
24	0	73	27
25	0	73	27
26	0	73	27
27	0	74	26
28	0	74	26
29	0	74	26
30	0	74	26

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

	Clearer (%)	Cloudier (%)
1	5	95
2	6	94
3	6	94
4	6	94
5	6	94
6	6	94
7	6	94
8	6	94
9	6	94
10	6	94
11	6	94
12	6	94
13	5	95
14	5	95
15	5	95
16	4	96
17	4	96
18	4	96
19	4	96
20	4	96
21	4	96
22	4	96
23	4	96
24	4	96
25	4	96
26	4	96
27	4	96
28	4	96
29	5	95
30	5	95

	Rain chance (%)
1	97
2	97
3	97
4	97
5	97
6	97
7	97
8	98
9	98
10	98
11	98
12	98
13	98
14	98
15	98
16	98
17	99
18	99
19	99
20	99
21	99
22	99
23	99
24	98
25	98
26	98
27	98
28	98
29	98
30	98

	Humid (%)	Muggy (%)	Oppressive (%)
1	1	86	13
2	1	86	13
3	1	86	13
4	1	85	14
5	1	85	14
6	1	84	15
7	0	85	15
8	0	84	16
9	0	83	17
10	0	82	18
11	0	81	19
12	0	80	20
13	0	79	21
14	0	78	22
15	0	77	23
16	0	77	23
17	0	76	24
18	0	75	25
19	0	74	26
20	0	74	26
21	0	74	26
22	0	73	27
23	0	73	27
24	0	73	27
25	0	73	27
26	0	73	27
27	0	74	26
28	0	74	26
29	0	74	26
30	0	74	26