Istres weather in September

In September, Istres sees average daytime highs of 26°C and overnight lows near 16°C, with 74 mm of rain across 6.3 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 3rd-wettest month of the year here.

Highs ease over the month, from about 28°C in the first days to 24°C by the end. The sky is clear or mostly clear about 56% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 hours at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Istres's 4th-clearest and 11th-windiest month. For the whole year in context, see Istres's year-round climate.

Daytime high
26°
4th warmest
Overnight low
16°
9th coldest
Rainfall
74 mm
6.3 wet days
Daylight
12 h 18 min
6:26 AM – 6:43 PM
Cloud cover
39%
4th clearest
Wind
14 km/h
11th windiest
Solar energy
4.76 kWh/m²
Travel score
7.5
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 28°C in the first days to 24°C by the end.

A typical September day in Istres reaches about 26°C in the afternoon and slips back to 16°C overnight — a 10°C spread between the day's warmth and the night's chill. On most days the high lands between 22°C and 29°C. Set against its neighbours, September runs about 5°C cooler than August and about 5°C warmer than October.

10°15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
12818
22818
32818
42818
52817
62817
72717
82717
92717
102717
112717
122617
132616
142616
152616
162616
172616
182516
192516
202516
212515
222515
232515
242415
252415
262415
272415
282415
292415
302314

Istres weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 3rd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan12° / 526.59.13.4
Feb13° / 385.410.24.1
Mar16° / 375.711.66.0
Apr19° / 10°60813.26.7
May23° / 14°506.514.57.5
Jun28° / 18°274.315.27.1
Jul31° / 20°152.814.95.9
Aug30° / 20°233.613.85.9
Sep26° / 16°746.312.37.5
Oct21° / 13°828.410.86.8
Nov16° / 859.49.55.0
Dec12° / 5078.83.6

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 56% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 15% of September, with mostly cloudy or overcast conditions the remaining 29%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
17624
27624
37624
47624
57624
67525
77525
87525
97525
107525
117426
127426
137426
147228
157228
167228
177129
187030
196931
206931
216931
226733
236733
246733
256634
266634
276634
286634
296535
306535

Chance of precipitation in September

Any precipitation

Istres gets around 74 mm of rain over 6.3 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 21% and peaks near 23% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%151015202530
Rain chance (%)
116
216
317
417
518
618
719
819
920
1020
1121
1221
1322
1422
1522
1623
1723
1823
1923
2023
2123
2223
2323
2423
2523
2623
2723
2823
2923
3023

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 42% of days. Sticky, muggy-or-worse air turns up on roughly 8% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1392125141
2402225131
3402225121
4402325111
5412325110
6412425100
740252590
840252590
940262580
1040272580
1139272580
1239282580
1339282580
1439292480
1539292470
1639302470
1740302370
1840312270
1941312270
2041312160
2142322160
2242322060
2343322050
2443321950
2544321950
2645321950
2746321940
2847311840
2948301830
3049301830

Wind in September

Winds average 14 km/h in September.

Across September, daily wind ranges from about 14 km/h on the calmest days to 14 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
114light breeze
214light breeze
314light breeze
414light breeze
514light breeze
614light breeze
714light breeze
814light breeze
914light breeze
1014light breeze
1114light breeze
1214light breeze
1314light breeze
1414light breeze
1514light breeze
1614light breeze
1714light breeze
1814light breeze
1914light breeze
2014light breeze
2114light breeze
2214light breeze
2314light breeze
2414light breeze
2514light breeze
2614light breeze
2714light breeze
2814light breeze
2914light breeze
3014light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 hours at the start of September to 11 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 84 minutes over September. Sunrise moves from 6:08 AM to 6:42 AM, and sunset from 7:11 PM to 6:17 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.06:087:11
213.06:097:09
312.96:117:08
412.96:127:06
512.86:137:04
612.86:147:02
712.76:157:00
812.76:166:58
912.66:186:56
1012.66:196:55
1112.56:206:53
1212.56:216:51
1312.46:226:49
1412.46:236:47
1512.36:246:45
1612.36:266:43
1712.26:276:41
1812.26:286:39
1912.16:296:37
2012.16:306:36
2112.06:316:34
2212.06:336:32
2311.96:346:30
2411.96:356:28
2511.86:366:26
2611.86:376:24
2711.76:386:22
2811.76:406:20
2911.66:416:19
3011.66:426:17

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.76 kWh/m².

For context, solar energy here swings from a low near 1.6 kWh/m² to a high of 7.31 kWh/m² in July across the year — September's 4.76 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.6Bright
25.5Bright
35.5Bright
45.4Bright
55.4Bright
65.3Bright
75.3Bright
85.2Bright
95.1Bright
105.1Bright
115.0Bright
125.0Bright
134.9Bright
144.8Bright
154.8Bright
164.7Bright
174.7Bright
184.6Bright
194.5Bright
204.5Bright
214.4Bright
224.4Bright
234.3Bright
244.3Bright
254.2Bright
264.2Bright
274.1Bright
284.1Bright
294.0Bright
304.0Moderate
Planning a trip in September

Is September a good time to visit Istres?

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

7.5
Sightseeing
1st-best month of the year
7.2
Beach & pool
4th-best month of the year

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

What to pack for Istres in September

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

In September, Istres sees daytime highs around 26°C and nights near 16°C. Worth packing: light clothes and sun protection. About 6 days see rain.

light clothessun protection

Sea temperature near Istres in September

The nearest coast averages about 21°C 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 18 km away) is warmest in August at about 22°C and coldest in February near 12°C.

It's comfortable for a long swim from Jun 28 to Sep 24 — about 2.9 months when the water holds above 20°C.

10°15°20°25°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°C)Comfort
Jan13Bracing
Feb12Bracing
Mar13Bracing
Apr14Bracing
May16Cool
Jun19Cool
Jul21Refreshing
Aug22Refreshing
Sep21Refreshing
Oct19Cool
Nov17Cool
Dec14Bracing

UV index in Istres in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 5 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Istres peaks around July 15 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJul 15UV 9Dec 22UV 1
UV index (midday)Level
Jan1Low
Feb2Moderate
Mar4Moderate
Apr6High
May6High
Jun7Very high
Jul9Very high
Aug7High
Sep5High
Oct3Moderate
Nov2Low
Dec1Low

Air quality in Istres 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 Istres is worst in March — around 17 µg/m³ PM2.5 (moderate), and holds fairly steady the rest of the year.

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

01020JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodMar 2417 µg/m³Nov 1911 µg/m³
PM2.5 (µg/m³)Level
Jan13Moderate
Feb15Moderate
Mar17Moderate
Apr17Moderate
May15Moderate
Jun16Moderate
Jul14Moderate
Aug15Moderate
Sep13Moderate
Oct13Moderate
Nov11Good
Dec12Moderate
Location & terrain

Where is Istres?

Istres sits at 43.5°N, 5.0°E, 14 m above sea level, in France. The nearest listed city is Miramas, 8.0 km away.

Topography around Istres

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Istres.

Within 3 km, the terrain around Istres has only modest variations in elevation — a maximum elevation change of 116 m around an average of 21 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 201 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,897 m.

The land around Istres is covered by water (30%), artificial surfaces (28%) and trees (20%) within 3 km, grassland (26%), water (24%) and trees (20%) within 16 km, and trees (38%) and water (31%) within 80 km.

3 km
116 m
16 km
201 m
80 km
1,897 m
treesshrubsgrasslandcroplandartificial surfacesbare terrainwaterwetland
September weather nearby: Miramas 8.0 km · Fos-sur-Mer 9.0 km · Port-de-Bouc 12 km · Martigues 13 km · Salon-de-Provence 17 km · Marignane 21 km · Vitrolles 22 km · Les Pennes-Mirabeau 28 km

France travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / E
230 V · 50 Hz
Prices
≈ 77% of US
price level, 2025
GDP per capita
$48,986
2025
Happiness
6.6 / 10
World Happiness, 2025
Safe drinking water
100%
of population, 2024
Homicide rate
1.3
per 100k, 2023
Road deaths
5.1
per 100k/yr, 2019
Income group
High
World Bank
English
Moderate
EF EPI 539
Religion
Roman Catholic 47%none 33%Muslim 4%Protestant 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 Istres (43.5134°, 4.9875°, elevation 14 m), 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).