La Roche-sur-Yon weather in September

In September, La Roche-sur-Yon sees average daytime highs of 22°C and overnight lows near 12°C, with 53 mm of rain across 7.7 wet days and about 12.4 hours of daylight. It is the 4th-warmest and 9th-wettest month of the year here.

Highs ease over the month, from about 23°C in the first days to 20°C by the end. The sky is clear or mostly clear about 29% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 12 min at the start of September to 11 h 30 min by month's end. Set against the rest of the year, September is La Roche-sur-Yon's 3rd-clearest and 10th-windiest month. For the whole year in context, see La Roche-sur-Yon's year-round climate.

Daytime high
22°
4th warmest
Overnight low
12°
9th coldest
Rainfall
53 mm
7.7 wet days
Daylight
12 h 18 min
6:50 AM – 7:10 PM
Cloud cover
56%
3rd clearest
Wind
13 km/h
10th windiest
Solar energy
4.06 kWh/m²
Travel score
6.9
out of 10
Air quality
Good
PM10 15.3 µg/m³ · 2019

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 23°C in the first days to 20°C by the end.

A typical September day in La Roche-sur-Yon reaches about 22°C in the afternoon and slips back to 12°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 18°C and 27°C. Set against its neighbours, September runs about 3°C cooler than August and about 4°C warmer than October.

10°15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12414
22314
32313
42313
52313
62313
72313
82313
92313
102313
112213
122213
132212
142212
152212
162212
172212
182212
192112
202112
212112
222112
232112
242112
252012
262011
272011
282011
292011
302011

How September really feels in La Roche-sur-Yon

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

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

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

La Roche-sur-Yon weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 9th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan / 7611.38.81.8
Feb10° / 589.6102.2
Mar13° / 5510.311.63.6
Apr16° / 5710.713.34.6
May19° / 10°6210.914.85.8
Jun22° / 13°47915.66.7
Jul24° / 15°417.515.37.4
Aug25° / 15°467.5147.4
Sep22° / 12°537.712.46.9
Oct17° / 10°781210.65.2
Nov13° / 7912.19.23.2
Dec10° / 8412.28.42.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 29% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 19% of September, with mostly cloudy or overcast conditions the remaining 51%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15347
25347
35347
45347
55347
65347
75347
85248
95248
105248
115248
125149
135248
145149
155149
165050
174951
184951
194852
204852
214852
224654
234555
244555
254456
264357
274258
284258
294258
304159

Chance of precipitation in September

Any precipitation

La Roche-sur-Yon gets around 53 mm of rain over 7.7 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 27% and peaks near 34% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%151015202530
Rain chance (%)
122
221
321
422
522
622
722
823
923
1024
1124
1225
1325
1425
1526
1626
1727
1827
1928
2028
2129
2229
2330
2430
2531
2632
2732
2833
2933
3034

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 57% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
14734172
24834162
35034151
45134141
55134141
65333131
75433121
85433121
95633110
105633110
115633110
125733100
135733100
14593290
15593290
16593290
17603280
18603280
19613270
20613270
21613270
22613270
23613270
24613270
25613270
26613270
27613270
28613270
29613270
30623260

Wind in September

Winds average 13 km/h in September.

Across September, daily wind ranges from about 13 km/h on the calmest days to 13 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
113light breeze
213light breeze
313light breeze
413light breeze
513light breeze
613light breeze
713light breeze
813light breeze
913light breeze
1013light breeze
1113light breeze
1213light breeze
1313light breeze
1413light breeze
1513light breeze
1613light breeze
1713light breeze
1813light breeze
1913light breeze
2013light breeze
2113light breeze
2213light breeze
2313light breeze
2413light breeze
2513light breeze
2613light breeze
2713light breeze
2813light breeze
2913light breeze
3013light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 12 min at the start of September to 11 h 30 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 102 minutes over September. Sunrise moves from 6:30 AM to 7:09 AM, and sunset from 7:41 PM to 6:41 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.26:307:41
213.16:327:39
313.16:337:37
413.06:347:35
512.96:367:33
612.96:377:30
712.86:387:28
812.86:407:26
912.76:417:24
1012.76:427:22
1112.66:447:20
1212.66:457:18
1312.56:467:16
1412.46:487:14
1512.46:497:12
1612.36:507:10
1712.36:527:08
1812.26:537:06
1912.26:547:04
2012.16:567:02
2112.06:576:59
2212.06:586:57
2311.97:006:55
2411.97:016:53
2511.87:026:51
2611.87:046:49
2711.77:056:47
2811.67:066:45
2911.67:086:43
3011.57:096:41

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.06 kWh/m².

For context, solar energy here swings from a low near 1.04 kWh/m² to a high of 6.19 kWh/m² in June across the year — September's 4.06 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.8Bright
24.7Bright
34.7Bright
44.6Bright
54.6Bright
64.5Bright
74.5Bright
84.5Bright
94.4Bright
104.3Bright
114.3Bright
124.2Bright
134.2Bright
144.1Bright
154.1Bright
164.0Bright
174.0Moderate
183.9Moderate
193.9Moderate
203.8Moderate
213.7Moderate
223.7Moderate
233.6Moderate
243.6Moderate
253.5Moderate
263.4Moderate
273.4Moderate
283.3Moderate
293.2Moderate
303.2Moderate
Planning a trip in September

Is September a good time to visit La Roche-sur-Yon?

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

6.9
Sightseeing
3rd-best month of the year
4.7
Beach & pool
4th-best month of the year

September is a reasonable time to visit La Roche-sur-Yon for sightseeing.

What to pack for La Roche-sur-Yon in September

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

In September, La Roche-sur-Yon sees daytime highs around 22°C and nights near 12°C. Little to plan around — just the basics. About 8 days see rain.

Sea temperature near La Roche-sur-Yon in September

The nearest coast averages about 18°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 33 km away) is warmest in August at about 20°C and coldest in February near 10°C.

The water stays below 20°C all year — cool enough that most swimmers want a wetsuit.

10°15°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshing
Sea temperature (°C)Comfort
Jan10Bracing
Feb10Bracing
Mar10Bracing
Apr12Bracing
May15Bracing
Jun17Cool
Jul19Cool
Aug20Cool
Sep18Cool
Oct17Cool
Nov14Bracing
Dec12Bracing

UV index in La Roche-sur-Yon 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 La Roche-sur-Yon peaks around July 24 at about 7 (very high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near January 1 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 7 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJul 24UV 7Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb2Low
Mar4Moderate
Apr5High
May6High
Jun7High
Jul7Very high
Aug7Very high
Sep5Moderate
Oct3Moderate
Nov2Low
Dec1Low
Location & terrain

Where is La Roche-sur-Yon?

La Roche-sur-Yon sits at 46.7°N, 1.4°W, 73 m above sea level, in France. The nearest listed city is Les Sables-d'Olonne, 33 km away.

Topography around La Roche-sur-Yon

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of La Roche-sur-Yon.

Within 3 km, the terrain around La Roche-sur-Yon has only modest variations in elevation — a maximum elevation change of 51 m around an average of 63 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 135 m; within 80 km, significant variations in elevation — a maximum elevation change of 339 m.

The land around La Roche-sur-Yon is covered by artificial surfaces (46%) and trees (26%) within 3 km, cropland (40%), grassland (31%) and trees (22%) within 16 km, and cropland (32%), water (27%) and grassland (26%) within 80 km.

3 km
51 m
16 km
135 m
80 km
339 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Les Sables-d'Olonne 33 km · Les Herbiers 39 km · Challans 40 km · Fontenay-le-Comte 53 km · Vertou 56 km · Bouguenais 59 km · Rezé 59 km · Cholet 60 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 La Roche-sur-Yon (46.6697°, -1.4276°, elevation 73 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. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).