Rancho Santa Margarita weather in September

In September, Rancho Santa Margarita sees average daytime highs of 85°F and overnight lows near 64°F, with 0.2 in of rain across 1.3 wet days and about 12.2 hours of daylight. It is the 3rd-warmest and 9th-wettest month of the year here.

Highs ease over the month, from about 88°F in the first days to 83°F by the end. The sky is clear or mostly clear about 86% of the time in September, and the air most often feels comfortable.

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 Rancho Santa Margarita's 2nd-clearest and 12th-windiest month. For the whole year in context, see Rancho Santa Margarita's year-round climate.

Daytime high
85°
3rd warmest
Overnight low
64°
10th coldest
Rainfall
0.2 in
1.3 wet days
Daylight
12 h 12 min
5:39 AM – 5:51 PM
Cloud cover
16%
2nd clearest
Wind
3 mph
12th windiest
Solar energy
6.15 kWh/m²
Travel score
6.9
out of 10

Rancho Santa Margarita is city in Orange County, California, United States.

Density
1,466/km²
people per km²
Founded
2000

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

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 88°F in the first days to 83°F by the end.

A typical September day in Rancho Santa Margarita reaches about 85°F in the afternoon and slips back to 64°F overnight — a 22°F spread between the day's warmth and the night's chill. On most days the high lands between 76°F and 94°F. Set against its neighbours, September runs about 3°F cooler than August and about 7°F warmer than October.

60°80°100°151015202530
Avg high (°F)Avg low (°F)
18866
28866
38866
48766
58766
68766
78765
88765
98665
108665
118665
128664
138564
148564
158564
168564
178563
188563
198563
208463
218463
228462
238462
248462
258462
268362
278362
288361
298361
308361

Rancho Santa Margarita weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 9th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysDaylight (hours)Travel score
Jan64° / 44°3.66.4106.5
Feb64° / 46°4.46.810.76.4
Mar67° / 48°2.66.511.76.9
Apr71° / 51°1.23.912.87.9
May74° / 56°0.62.313.78.7
Jun80° / 60°0.10.614.28.6
Jul86° / 65°0.10.6146.7
Aug88° / 66°0.10.313.26.1
Sep85° / 64°0.21.312.26.9
Oct79° / 57°0.92.811.28.5
Nov70° / 49°1.23.210.38.0
Dec64° / 44°2.55.39.86.6

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 5% 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 (%)
1937
2946
3946
4946
5946
6946
7946
8946
9946
10937
11937
12937
13937
14937
15937
16928
17928
18928
19928
20919
219010
229010
239010
248911
258911
268911
278911
288911
298812
308812

Chance of precipitation in September

Any precipitation

Rancho Santa Margarita gets around 0.2 in of rain over 1.3 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 4% and peaks near 5% on the wettest days.

0%10%20%30%151015202530
Rain chance (%)
13
23
33
43
54
64
74
84
94
104
114
124
134
144
154
164
174
184
194
205
215
225
235
245
255
265
275
285
295
305

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the comfortable band about 45% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
1938449
21038439
31139429
41140409
51240399
61341379
71442368
81443358
91544337
101645327
111746316
121847305
131848295
141949284
152049274
162149263
172250253
182349253
192449242
202549242
212648232
222748232
232848222
242947212
253147212
263246202
273446192
283645172
293845162
304044152

Wind in September

Winds average 3 mph in September, the calmest month.

Across September, daily wind ranges from about 3 mph on the calmest days to 3 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
13calm
23calm
33calm
43calm
53calm
63calm
73calm
83calm
93calm
103calm
113calm
123calm
133calm
143calm
153calm
163calm
173calm
183calm
193calm
203calm
213calm
223calm
233calm
243calm
253calm
263calm
273calm
283calm
293calm
303calm

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 5:28 AM to 5:49 AM, and sunset from 6:12 PM to 5:31 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.75:286:12
212.75:296:11
312.75:306:09
412.65:306:08
512.65:316:07
612.65:326:05
712.55:326:04
812.55:336:02
912.55:346:01
1012.45:346:00
1112.45:355:58
1212.35:365:57
1312.35:365:55
1412.35:375:54
1512.25:385:52
1612.25:395:51
1712.25:395:49
1812.15:405:48
1912.15:415:47
2012.15:415:45
2112.05:425:44
2212.05:435:42
2312.05:435:41
2411.95:445:39
2511.95:455:38
2611.85:465:37
2711.85:465:35
2811.85:475:34
2911.75:485:32
3011.75:495:31

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6.15 kWh/m².

For context, solar energy here swings from a low near 2.99 kWh/m² to a high of 7.98 kWh/m² in June across the year — September's 6.15 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
235.8Bright
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 Rancho Santa Margarita?

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

6.9
Sightseeing
6th-best month of the year
9.0
Beach & pool
2nd-best month of the year

September is a reasonable time to visit Rancho Santa Margarita for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Rancho Santa Margarita in September

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

In September, Rancho Santa Margarita sees daytime highs around 85°F and nights near 64°F. Pack light clothes and sun protection.

light clothessun protection

Sea temperature near Rancho Santa Margarita in September

The nearest coast averages about 69°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 16 mi away) is warmest in August at about 69°F and coldest in February near 59°F.

It's comfortable for a long swim from Jul 13 to Sep 28 — about 2.6 months when the water holds above 68°F.

60°65°70°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingcomfortable to swim
Sea temperature (°F)Comfort
Jan59Cool
Feb59Cool
Mar59Cool
Apr60Cool
May63Cool
Jun65Cool
Jul68Refreshing
Aug69Refreshing
Sep69Refreshing
Oct67Cool
Nov64Cool
Dec60Cool

UV index in Rancho Santa Margarita in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 8 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Rancho Santa Margarita peaks around June 23 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 16 at about 3 (moderate).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateVery highExtremeVery highHighModerateJun 23UV 10Dec 16UV 3
UV index (midday)Level
Jan4Moderate
Feb5Moderate
Mar5Moderate
Apr8Very high
May8Very high
Jun11Extreme
Jul10Extreme
Aug10Extreme
Sep8Very high
Oct6High
Nov3Moderate
Dec3Moderate

Air quality in Rancho Santa Margarita 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 Rancho Santa Margarita is worst in September — around 49 µg/m³ PM2.5 (poor), about 4.0× the cleanest month (May, 12 µg/m³).

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

0204060JanFebMarAprMayJunJulAugSepOctNovDecModeratePoorModerateSep 1447 µg/m³May 1713 µg/m³
PM2.5 (µg/m³)Level
Jan18Moderate
Feb19Moderate
Mar19Moderate
Apr17Moderate
May12Moderate
Jun17Moderate
Jul19Moderate
Aug32Moderate
Sep49Poor
Oct21Moderate
Nov21Moderate
Dec18Moderate
Location & terrain

Where is Rancho Santa Margarita?

Rancho Santa Margarita sits at 33.6°N, 117.6°W, 948 ft above sea level, in United States. The nearest listed city is Mission Viejo, 5.0 mi away.

Topography around Rancho Santa Margarita

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

Within 2 miles, the terrain around Rancho Santa Margarita has only modest variations in elevation — a maximum elevation change of 764 ft around an average of 1,007 ft above sea level; within 10 miles, very significant variations in elevation — a maximum elevation change of 5,564 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 9,967 ft.

The land around Rancho Santa Margarita is covered by artificial surfaces (41%) and trees (35%) within 2 miles, trees (43%) and artificial surfaces (21%) within 10 miles, and water (27%) and artificial surfaces (25%) within 50 miles.

2 miles
764 ft
10 miles
5,564 ft
50 miles
9,967 ft
treesshrubsgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Mission Viejo 5.0 mi · Lake Forest 5.0 mi · Ladera Ranch 5.0 mi · Laguna Hills 6.8 mi · Laguna Woods 7.5 mi · Aliso Viejo 8.7 mi · Stonegate 9.3 mi · Laguna Niguel 9.9 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 Rancho Santa Margarita (33.6409°, -117.6031°, elevation 948 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).