Santa Cruz weather in September

In September, Santa Cruz sees average daytime highs of 64°F and overnight lows near 58°F, with 0.1 in of rain across 0.6 wet days and about 12.3 hours of daylight. It is the 1st-warmest and 10th-wettest month of the year here.

Day-to-day highs hold fairly steady near 64°F through the month. The sky is clear or mostly clear about 86% of the time in September, and the air most often feels dry.

Daylight stretches from about 12 h 48 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Santa Cruz's 2nd-clearest and 10th-windiest month. For the whole year in context, see Santa Cruz's year-round climate.

Daytime high
64°
1st warmest
Overnight low
58°
12th coldest
Rainfall
0.1 in
0.6 wet days
Daylight
12 h 12 min
5:55 AM – 6:09 PM
Cloud cover
17%
2nd clearest
Wind
7 mph
10th windiest
Solar energy
5.78 kWh/m²
Travel score
7.9
out of 10

Santa Cruz is city in and county seat of Santa Cruz County, California, United States.

Density
1,567/km²
people per km²
Founded
1791

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 64°F through the month.

A typical September day in Santa Cruz reaches about 64°F in the afternoon and slips back to 58°F overnight — a 6°F spread between the day's warmth and the night's chill. On most days the high lands between 60°F and 69°F. Set against its neighbours, September runs on par with August and on par with October.

50°60°70°80°151015202530
Avg high (°F)Avg low (°F)
16458
26458
36458
46458
56458
66458
76458
86458
96458
106458
116458
126458
136458
146458
156458
166458
176458
186458
196458
206458
216458
226458
236458
246458
256458
266457
276457
286457
296457
306457

Santa Cruz weather by month

How September compares with the rest of the year at a glance. September is the 1st-warmest and 10th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysDaylight (hours)Travel score
Jan56° / 49°5.79.69.83.8
Feb56° / 49°5.69.410.63.8
Mar56° / 50°3.99.111.74.1
Apr57° / 51°1.8512.94.7
May58° / 52°0.8313.95.4
Jun60° / 54°0.20.914.56.5
Jul62° / 56°0.00.114.37.2
Aug63° / 57°0.00.113.47.8
Sep64° / 58°0.10.612.37.9
Oct63° / 56°1.22.9117.1
Nov59° / 52°2.66.1105.2
Dec56° / 49°5.39.69.53.9

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 86% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 7% of September, with mostly cloudy or overcast conditions the remaining 8%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1955
2946
3946
4946
5946
6946
7946
8946
9946
10946
11946
12946
13946
14937
15937
16928
17928
18928
19928
20928
21919
22919
239010
248911
258911
268911
278911
288812
298812
308812

Chance of precipitation in September

Any precipitation

Santa Cruz 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 4% on the wettest days.

0%10%20%30%151015202530
Rain chance (%)
10
20
31
41
51
61
71
81
91
102
112
122
132
142
152
163
173
183
193
203
213
223
233
243
253
263
273
284
294
304

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 59% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)
153452
254442
354442
455432
555432
656422
756422
856422
956422
1057412
1157412
1257412
1358411
1458411
1558411
1658411
1758411
1858411
1958411
2058411
2159401
2260400
2361390
2461390
2562380
2663370
2764360
2865350
2966340
3067330

Wind in September

Winds average 7 mph in September.

Across September, daily wind ranges from about 7 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
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 48 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 66 minutes over September. Sunrise moves from 5:43 AM to 6:07 AM, and sunset from 6:33 PM to 5:47 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:436:33
212.85:446:31
312.85:456:30
412.75:456:28
512.75:466:27
612.65:476:25
712.65:486:24
812.65:496:22
912.55:506:20
1012.55:506:19
1112.45:516:17
1212.45:526:16
1312.45:536:14
1412.35:546:13
1512.35:556:11
1612.25:556:09
1712.25:566:08
1812.25:576:06
1912.15:586:05
2012.15:596:03
2112.06:006:02
2212.06:016:00
2311.96:015:58
2411.96:025:57
2511.96:035:55
2611.86:045:54
2711.86:055:52
2811.76:065:51
2911.76:075:49
3011.76:075:47

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.78 kWh/m².

For context, solar energy here swings from a low near 2.37 kWh/m² to a high of 7.7 kWh/m² in June across the year — September's 5.78 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
16.4Intense
26.4Intense
36.3Intense
46.3Intense
56.2Intense
66.2Intense
76.2Intense
86.1Intense
96.1Intense
106.0Intense
116.0Bright
125.9Bright
135.9Bright
145.8Bright
155.8Bright
165.8Bright
175.7Bright
185.7Bright
195.6Bright
205.6Bright
215.5Bright
225.5Bright
235.4Bright
245.4Bright
255.3Bright
265.3Bright
275.3Bright
285.2Bright
295.2Bright
305.1Bright
Planning a trip in September

Hazard calendar for Santa Cruz

In seasonPeak

None of Santa Cruz's seasonal hazards are active in September. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Santa Cruz's rainy season runs November–March, when most of the year's rain falls.

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

Is September a good time to visit Santa Cruz?

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

7.9
Sightseeing
1st-best month of the year
2.5
Beach & pool
1st-best month of the year

September is one of the better times to visit Santa Cruz for general sightseeing.

What to pack for Santa Cruz in September

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

In September, Santa Cruz sees daytime highs around 64°F and nights near 58°F. Worth packing: sun protection.

sun protection

Sea temperature near Santa Cruz in September

The nearest coast averages about 58°F in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 9 mi away) is warmest in September at about 58°F and coldest in April near 54°F.

The water stays below 68°F all year — cool enough that most swimmers want a wetsuit.

52°54°56°58°60°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°F)Comfort
Jan55Bracing
Feb55Bracing
Mar55Bracing
Apr54Bracing
May54Bracing
Jun55Bracing
Jul57Bracing
Aug58Bracing
Sep58Bracing
Oct58Bracing
Nov57Bracing
Dec55Bracing

UV index in Santa Cruz in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Santa Cruz peaks around June 23 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 13 at about 2 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 9 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highHighModerateJun 23UV 10Dec 13UV 2
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar5Moderate
Apr7High
May8Very high
Jun10Extreme
Jul10Extreme
Aug10Very high
Sep6High
Oct5High
Nov2Moderate
Dec2Moderate

Air quality in Santa Cruz 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 Santa Cruz is worst in August — around 17 µg/m³ PM2.5 (moderate), about 2.9× the cleanest month (June, 6 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodAug 1816 µg/m³Jun 186 µg/m³
PM2.5 (µg/m³)Level
Jan7Good
Feb9Good
Mar8Good
Apr7Good
May7Good
Jun6Good
Jul6Good
Aug17Moderate
Sep11Good
Oct10Good
Nov9Good
Dec6Good
Location & terrain

Where is Santa Cruz?

Santa Cruz sits at 37.0°N, 122.0°W, 36 ft above sea level, in United States. The nearest listed city is Live Oak, 3.1 mi away.

Topography around Santa Cruz

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

Within 2 miles, the terrain around Santa Cruz has only modest variations in elevation — a maximum elevation change of 755 ft around an average of 131 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,520 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 4,820 ft.

The land around Santa Cruz is covered by artificial surfaces (44%) and trees (30%) within 2 miles, water (46%) and trees (42%) within 10 miles, and water (33%), trees (29%) and grassland (25%) within 50 miles.

2 miles
755 ft
10 miles
2,520 ft
50 miles
4,820 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Live Oak 3.1 mi · Watsonville 16 mi · Los Gatos 18 mi · Saratoga 20 mi · Campbell 22 mi · Morgan Hill 24 mi · Marina 24 mi · Cupertino 24 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 Santa Cruz (36.9741°, -122.0308°, elevation 36 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).