Porterville weather in September

In September, Porterville sees average daytime highs of 87°F and overnight lows near 64°F, with 0.1 in of rain across 0.4 wet days and about 12.2 hours of daylight. It is the 3rd-warmest and 10th-wettest month of the year here.

Highs ease over the month, from about 91°F in the first days to 84°F by the end. The sky is clear or mostly clear about 87% 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 Porterville's 2nd-clearest and 5th-windiest month. For the whole year in context, see Porterville's year-round climate.

Daytime high
87°
3rd warmest
Overnight low
64°
10th coldest
Rainfall
0.1 in
0.4 wet days
Daylight
12 h 12 min
5:44 AM – 5:57 PM
Cloud cover
13%
2nd clearest
Wind
4 mph
5th windiest
Solar energy
6.22 kWh/m²
Travel score
6.3
out of 10

Porterville is city in Tulare County, California, United States.

Density
1,224/km²
people per km²
Founded
1902

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 91°F in the first days to 84°F by the end.

A typical September day in Porterville reaches about 87°F in the afternoon and slips back to 64°F overnight — a 24°F spread between the day's warmth and the night's chill. On most days the high lands between 78°F and 96°F. Set against its neighbours, September runs about 6°F cooler than August and about 10°F warmer than October.

60°80°100°151015202530
Avg high (°F)Avg low (°F)
19267
29167
39167
49167
59166
69066
79066
89066
98965
108965
118965
128865
138864
148864
158764
168764
178763
188763
198663
208662
218662
228662
238562
248562
258561
268461
278461
288460
298360
308360

How September really feels in Porterville

Once humidity and wind are folded in, September averages 8 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
8
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

The story in September is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Porterville weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 10th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysDaylight (hours)Travel score
Jan58° / 42°3.28.89.84.6
Feb61° / 44°3.21010.65.0
Mar65° / 47°3.39.711.76.1
Apr70° / 50°1.76.212.97.3
May78° / 57°0.93.513.98.2
Jun87° / 64°0.20.814.46.3
Jul94° / 70°0.00.314.24.0
Aug93° / 69°0.00.213.44.1
Sep87° / 64°0.10.412.26.3
Oct77° / 55°0.72.811.18.5
Nov65° / 46°1.8610.16.7
Dec58° / 41°2.98.29.64.6

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 87% 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 6%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1964
2964
3964
4964
5964
6964
7964
8955
9955
10955
11955
12955
13955
14946
15946
16946
17946
18946
19946
20946
21946
22946
23937
24937
25937
26937
27937
28928
29928
30919

Chance of precipitation in September

Any precipitation

Porterville gets around 0.1 in of rain over 0.4 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 2% and peaks near 4% on the wettest days.

0%10%20%30%151015202530
Rain chance (%)
11
21
31
41
51
61
71
81
90
100
110
121
131
141
151
161
171
181
192
202
212
222
232
243
253
263
274
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 82% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
1722062
2741952
3751852
4751852
5751852
6761842
7781741
8781741
9791731
10801631
11811621
12811621
13811621
14831520
15831520
16841510
17841510
18841510
19841420
20841420
21841420
22851320
23851320
24851320
25851320
26851320
27851320
28851320
29851320
30851320

Wind in September

Winds average 4 mph in September.

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
104calm
114calm
124calm
134calm
144calm
154calm
164calm
174calm
184calm
194calm
204calm
214calm
224calm
234calm
243calm
253calm
263calm
273calm
283calm
293calm
303calm

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 5:32 AM to 5:55 AM, and sunset from 6:20 PM to 5:36 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:326:20
212.85:326:18
312.75:336:17
412.75:346:15
512.75:356:14
612.65:366:12
712.65:366:11
812.55:376:09
912.55:386:08
1012.55:396:06
1112.45:406:05
1212.45:406:03
1312.35:416:02
1412.35:426:00
1512.35:435:59
1612.25:445:57
1712.25:445:56
1812.15:455:54
1912.15:465:53
2012.15:475:51
2112.05:485:49
2212.05:485:48
2312.05:495:46
2411.95:505:45
2511.95:515:43
2611.85:525:42
2711.85:535:40
2811.85:535:39
2911.75:545:37
3011.75:555:36

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6.22 kWh/m².

For context, solar energy here swings from a low near 2.52 kWh/m² to a high of 8.25 kWh/m² in June across the year — September's 6.22 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
86.6Intense
96.5Intense
106.5Intense
116.4Intense
126.4Intense
136.3Intense
146.3Intense
156.3Intense
166.2Intense
176.2Intense
186.1Intense
196.1Intense
206.0Intense
216.0Bright
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 Porterville?

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

6.3
Sightseeing
5th-best month of the year
8.9
Beach & pool
1st-best month of the year

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

What to pack for Porterville in September

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

In September, Porterville sees daytime highs around 87°F and nights near 64°F. Pack light clothes and sun protection.

light clothessun protection

UV index in Porterville in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Porterville peaks around June 20 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 15 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 20UV 10Dec 15UV 2
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar5Moderate
Apr7High
May8Very high
Jun11Extreme
Jul10Very high
Aug10Very high
Sep7Very high
Oct5High
Nov3Moderate
Dec2Moderate

Air quality in Porterville 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 Porterville is worst in September — around 69 µg/m³ PM2.5 (unhealthy), about 7.3× the cleanest month (May, 10 µg/m³).

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

020406080JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodModerateUnhealthyModerateSep 1665 µg/m³May 2410 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb13Moderate
Mar15Moderate
Apr12Good
May10Good
Jun10Good
Jul17Moderate
Aug33Moderate
Sep69Unhealthy
Oct36Poor
Nov16Moderate
Dec14Moderate
Location & terrain

Where is Porterville?

Porterville sits at 36.1°N, 119.0°W, 459 ft above sea level, in United States. The nearest listed city is Tulare, 21 mi away.

Topography around Porterville

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

Within 2 miles, the terrain around Porterville has only modest variations in elevation — a maximum elevation change of 417 ft around an average of 469 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,926 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 13,510 ft.

The land around Porterville is covered by artificial surfaces (55%) and grassland (20%) within 2 miles, grassland (47%) and trees (25%) within 10 miles, and trees (36%) and grassland (35%) within 50 miles.

2 miles
417 ft
10 miles
1,926 ft
50 miles
13,510 ft
treesshrubsgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Tulare 21 mi · Visalia 24 mi · Delano 24 mi · Corcoran 30 mi · Wasco 37 mi · Dinuba 39 mi · Hanford 40 mi · Shafter 42 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 Porterville (36.0652°, -119.0168°, elevation 459 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. 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).