La Jolla weather in September

In September, La Jolla sees average daytime highs of 74°F and overnight lows near 65°F, with 0.1 in of rain across 0.6 wet days and about 12.2 hours of daylight. It is the 2nd-warmest and 9th-wettest month of the year here.

Day-to-day highs hold fairly steady near 74°F through the month. The sky is clear or mostly clear about 81% of the time in September, and the air most often feels humid.

Daylight stretches from about 12 h 42 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is La Jolla's 2nd-clearest and 6th-windiest month. For the whole year in context, see La Jolla's year-round climate.

Daytime high
74°
2nd warmest
Overnight low
65°
11th coldest
Rainfall
0.1 in
0.6 wet days
Daylight
12 h 12 min
5:37 AM – 5:49 PM
Cloud cover
21%
2nd clearest
Wind
7 mph
6th windiest
Solar energy
6.16 kWh/m²
Travel score
9.2
out of 10

La Jolla is neighborhood in San Diego, California, United States.

Founded
1850

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

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 74°F through the month.

A typical September day in La Jolla reaches about 74°F in the afternoon and slips back to 65°F overnight — a 9°F spread between the day's warmth and the night's chill. On most days the high lands between 69°F and 80°F. Set against its neighbours, September runs on par with August and about 3°F warmer than October.

60°70°80°151015202530
Avg high (°F)Avg low (°F)
17566
27566
37566
47566
57566
67566
77466
87466
97466
107466
117465
127465
137465
147465
157465
167465
177465
187465
197365
207365
217365
227365
237365
247364
257364
267364
277364
287364
297364
307364

La Jolla weather by month

How September compares with the rest of the year at a glance. September is the 2nd-warmest and 9th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysDaylight (hours)Travel score
Jan62° / 52°2.05.510.16.1
Feb62° / 53°2.56.210.85.9
Mar63° / 54°1.55.211.86.3
Apr64° / 56°0.62.912.87.2
May66° / 58°0.31.613.77.7
Jun69° / 61°0.00.214.18.4
Jul72° / 64°0.10.313.99.0
Aug74° / 66°0.00.113.29.4
Sep74° / 65°0.10.612.29.2
Oct71° / 62°0.5211.28.4
Nov67° / 57°0.72.910.37.6
Dec62° / 53°1.64.99.96.4

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 81% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 9% of September, with mostly cloudy or overcast conditions the remaining 9%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1946
2946
3946
4946
5946
6937
7937
8937
9937
10928
11928
12928
13928
14928
15919
16919
17919
189010
199010
208911
218911
228911
238812
248812
258713
268713
278614
288614
298614
308614

Chance of precipitation in September

Any precipitation

La Jolla gets around 0.1 in of rain over 0.6 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 2% and peaks near 3% on the wettest days.

0%10%20%30%151015202530
Rain chance (%)
11
21
31
41
51
61
71
81
92
102
112
122
132
142
152
162
173
183
193
203
213
223
233
243
253
263
273
283
293
303

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the humid band about 52% of days. Sticky, muggy-or-worse air turns up on roughly 19% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
101458271
211555281
311654281
411754271
511853271
611953261
712151261
812251251
912351241
1012451231
1122551211
1222651201
1322652191
1422752181
1532851171
1632852161
1732853151
1842853141
1942853141
2042854131
2142855130
2252854130
2352854130
2462854120
2562953120
2662953120
2773051120
2883150110
2983248110
3093447100

Wind in September

Winds average 7 mph in September.

Across September, daily wind ranges from about 6 mph on the calmest days to 7 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 42 min at the start of September to 11 h 42 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 60 minutes over September. Sunrise moves from 5:27 AM to 5:47 AM, and sunset from 6:10 PM to 5:30 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.75:276:10
212.75:286:09
312.65:296:07
412.65:296:06
512.65:306:05
612.55:316:03
712.55:316:02
812.55:326:01
912.45:335:59
1012.45:335:58
1112.45:345:56
1212.35:355:55
1312.35:355:54
1412.35:365:52
1512.25:375:51
1612.25:375:49
1712.25:385:48
1812.15:395:47
1912.15:395:45
2012.15:405:44
2112.05:415:42
2212.05:415:41
2312.05:425:40
2411.95:435:38
2511.95:445:37
2611.95:445:35
2711.85:455:34
2811.85:465:33
2911.75:465:31
3011.75:475:30

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6.16 kWh/m².

For context, solar energy here swings from a low near 3.12 kWh/m² to a high of 7.89 kWh/m² in June across the year — September's 6.16 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
16.7Intense
26.7Intense
36.7Intense
46.6Intense
56.6Intense
66.5Intense
76.5Intense
86.5Intense
96.4Intense
106.4Intense
116.3Intense
126.3Intense
136.3Intense
146.2Intense
156.2Intense
166.2Intense
176.1Intense
186.1Intense
196.0Intense
206.0Bright
215.9Bright
225.9Bright
235.9Bright
245.8Bright
255.8Bright
265.7Bright
275.7Bright
285.6Bright
295.6Bright
305.5Bright
Planning a trip in September

Is September a good time to visit La Jolla?

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

9.2
Sightseeing
2nd-best month of the year
7.2
Beach & pool
2nd-best month of the year

September is one of the better times to visit La Jolla for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for La Jolla in September

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

In September, La Jolla sees daytime highs around 74°F and nights near 65°F. Pack sun protection. Worth having: light clothes.

sun protectionlight clothes

Sea temperature near La Jolla in September

The nearest coast averages about 70°F in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea offshore is warmest in August at about 70°F and coldest in February near 59°F.

It's comfortable for a long swim from Jul 8 to Oct 6 — about 3 months when the water holds above 68°F.

60°65°70°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingcomfortable to swim
Sea temperature (°F)Comfort
Jan60Cool
Feb59Cool
Mar60Cool
Apr61Cool
May64Cool
Jun66Cool
Jul69Refreshing
Aug70Refreshing
Sep70Refreshing
Oct67Cool
Nov64Cool
Dec61Cool

UV index in La Jolla in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 8 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in La Jolla peaks around June 23 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 11 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highHighModerateJun 23UV 11Dec 17UV 3
UV index (midday)Level
Jan4Moderate
Feb5Moderate
Mar5High
Apr8Very high
May8Very high
Jun11Extreme
Jul11Extreme
Aug10Extreme
Sep8Very high
Oct6High
Nov4Moderate
Dec3Moderate

Air quality in La Jolla 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 La Jolla is worst in September — around 26 µg/m³ PM2.5 (moderate), about 3.4× the cleanest month (May, 8 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateSep 1625 µg/m³May 168 µg/m³
PM2.5 (µg/m³)Level
Jan12Good
Feb12Moderate
Mar12Moderate
Apr11Good
May8Good
Jun11Good
Jul11Good
Aug15Moderate
Sep26Moderate
Oct14Moderate
Nov12Moderate
Dec16Moderate
Location & terrain

Where is La Jolla?

La Jolla sits at 32.8°N, 117.3°W, 105 ft above sea level, in United States. The nearest listed city is Mira Mesa, 8.7 mi away.

Topography around La Jolla

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of La Jolla.

Within 2 miles, the terrain around La Jolla has only modest variations in elevation — a maximum elevation change of 810 ft around an average of 128 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 814 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 6,450 ft.

The land around La Jolla is covered by water (58%) and artificial surfaces (25%) within 2 miles, water (57%) and artificial surfaces (25%) within 10 miles, and water (37%) and shrubs (20%) within 50 miles.

2 miles
810 ft
10 miles
814 ft
50 miles
6,450 ft
treesshrubsgrasslandartificial surfacesbare terrainwater
September weather nearby: Mira Mesa 8.7 mi · San Diego 11 mi · Rancho Penasquitos 12 mi · Coronado 12 mi · Encinitas 13 mi · National City 16 mi · La Mesa 16 mi · Lemon Grove 16 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

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 La Jolla (32.8473°, -117.2742°, elevation 105 ft), 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. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. 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).