Sylmar weather in September

In September, Sylmar sees average daytime highs of 86°F and overnight lows near 62°F, with 0.1 in of rain across 0.6 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 84°F by the end. 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 Sylmar's 2nd-clearest and 12th-windiest month. For the whole year in context, see Sylmar's year-round climate.

Daytime high
86°
3rd warmest
Overnight low
62°
10th coldest
Rainfall
0.1 in
0.6 wet days
Daylight
12 h 12 min
5:42 AM – 5:54 PM
Cloud cover
14%
2nd clearest
Wind
3 mph
12th windiest
Solar energy
6.23 kWh/m²
Travel score
6.8
out of 10

Sylmar is neighborhood of Los Angeles, California, United States.

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 84°F by the end.

A typical September day in Sylmar reaches about 86°F in the afternoon and slips back to 62°F overnight — a 24°F spread between the day's warmth and the night's chill. On most days the high lands between 76°F and 95°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)
18965
28865
38865
48864
58864
68864
78764
88764
98764
108763
118663
128663
138662
148662
158562
168562
178562
188562
198561
208561
218561
228561
238561
248561
258460
268460
278460
288460
298460
308359

Sylmar 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°3.55.6106.5
Feb64° / 45°3.86.710.76.5
Mar67° / 47°2.65.911.77.1
Apr72° / 50°0.93.112.88.1
May76° / 55°0.41.813.88.8
Jun81° / 59°0.10.514.28.4
Jul87° / 64°0.10.414.16.5
Aug89° / 65°0.00.113.35.9
Sep86° / 62°0.10.612.26.8
Oct79° / 56°0.72.511.18.5
Nov70° / 49°0.82.710.28.2
Dec63° / 43°2.359.86.6

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 6% of September, with mostly cloudy or overcast conditions the remaining 7%. 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
14946
15937
16937
17937
18937
19937
20937
21919
22919
23919
24919
25919
269010
279010
289010
299010
309010

Chance of precipitation in September

Any precipitation

Sylmar 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 5% on the wettest days.

0%10%20%30%151015202530
Rain chance (%)
11
21
31
41
51
62
72
82
92
102
111
121
132
142
152
162
172
182
192
202
212
222
232
243
253
263
274
284
294
305

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 53% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
13647161
23746151
33846152
43945152
54044142
64144142
74243132
84442121
94542121
104641111
114841101
124940101
13513991
14513991
15533881
16553780
17563680
18573580
19583480
20593470
21603370
22613270
23623170
24633070
25643060
26652960
27662860
28682750
29692650
30702550

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 4 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
214calm
224calm
234calm
244calm
254calm
264calm
274calm
284calm
294calm
304calm

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 5:31 AM to 5:52 AM, and sunset from 6:16 PM to 5:34 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:316:16
212.75:326:15
312.75:326:13
412.65:336:12
512.65:346:10
612.65:356:09
712.55:356:08
812.55:366:06
912.55:376:05
1012.45:376:03
1112.45:386:02
1212.45:396:00
1312.35:405:59
1412.35:405:57
1512.25:415:56
1612.25:425:54
1712.25:435:53
1812.15:435:52
1912.15:445:50
2012.15:455:49
2112.05:455:47
2212.05:465:46
2312.05:475:44
2411.95:485:43
2511.95:485:41
2611.85:495:40
2711.85:505:38
2811.85:515:37
2911.75:515:35
3011.75:525:34

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6.23 kWh/m².

For context, solar energy here swings from a low near 2.96 kWh/m² to a high of 8.13 kWh/m² in June across the year — September's 6.23 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
16.8Intense
26.8Intense
36.8Intense
46.7Intense
56.7Intense
66.6Intense
76.6Intense
86.5Intense
96.5Intense
106.5Intense
116.4Intense
126.4Intense
136.3Intense
146.3Intense
156.3Intense
166.2Intense
176.2Intense
186.1Intense
196.1Intense
206.0Intense
216.0Intense
226.0Bright
235.9Bright
245.9Bright
255.8Bright
265.8Bright
275.7Bright
285.7Bright
295.6Bright
305.6Bright
Planning a trip in September

Is September a good time to visit Sylmar?

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

6.8
Sightseeing
7th-best month of the year
9.1
Beach & pool
1st-best month of the year

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

What to pack for Sylmar in September

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

In September, Sylmar sees daytime highs around 86°F and nights near 62°F. Pack light clothes and sun protection.

light clothessun protection

Sea temperature near Sylmar in September

The nearest coast averages about 68°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 30 mi away) is warmest in August at about 68°F and coldest in February near 59°F.

It's comfortable for a long swim from Aug 4 to Sep 13 — about 1.3 months when the water holds above 68°F.

60°65°70°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshing
Sea temperature (°F)Comfort
Jan59Bracing
Feb59Bracing
Mar59Bracing
Apr59Cool
May62Cool
Jun65Cool
Jul67Cool
Aug68Refreshing
Sep68Refreshing
Oct66Cool
Nov63Cool
Dec60Cool

UV index in Sylmar 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 Sylmar peaks around June 23 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 15 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 15UV 3
UV index (midday)Level
Jan4Moderate
Feb5Moderate
Mar5Moderate
Apr8Very high
May8Very high
Jun11Extreme
Jul11Extreme
Aug11Extreme
Sep8Very high
Oct6High
Nov3Moderate
Dec3Moderate

Air quality in Sylmar 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 Sylmar is worst in December — around 29 µg/m³ PM2.5 (moderate), about 2.4× the cleanest month (May, 12 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateDec 1428 µg/m³May 1812 µg/m³
PM2.5 (µg/m³)Level
Jan18Moderate
Feb17Moderate
Mar17Moderate
Apr15Moderate
May12Good
Jun14Moderate
Jul25Moderate
Aug26Moderate
Sep24Moderate
Oct18Moderate
Nov23Moderate
Dec29Moderate
Location & terrain

Where is Sylmar?

Sylmar sits at 34.3°N, 118.4°W, 1,253 ft above sea level, in United States. The nearest listed city is San Fernando, 1.9 mi away.

Topography around Sylmar

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

Within 2 miles, the terrain around Sylmar has significant variations in elevation — a maximum elevation change of 1,299 ft around an average of 1,306 ft above sea level; within 10 miles, very significant variations in elevation — a maximum elevation change of 4,239 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 10,013 ft.

The land around Sylmar is covered by artificial surfaces (73%) within 2 miles, artificial surfaces (41%) and shrubs (20%) within 10 miles, and grassland (26%) within 50 miles.

2 miles
1,299 ft
10 miles
4,239 ft
50 miles
10,013 ft
treesshrubsgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: San Fernando 1.9 mi · North Hills 5.6 mi · Northridge 7.5 mi · Santa Clarita 8.1 mi · Canyon Country 8.1 mi · Van Nuys 8.1 mi · Valley Glen 8.7 mi · Sunland 8.7 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 Sylmar (34.3078°, -118.4493°, elevation 1,253 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).