Vernon weather in September

In September, Vernon sees average daytime highs of 20°C and overnight lows near 11°C, with 44 mm of rain across 8.5 wet days and about 12.4 hours of daylight. It is the 4th-warmest and 12th-wettest month of the year here.

Highs ease over the month, from about 22°C in the first days to 19°C by the end. The sky is clear or mostly clear about 21% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 18 min at the start of September to 11 h 30 min by month's end. Set against the rest of the year, September is Vernon's 3rd-clearest and 9th-windiest month. For the whole year in context, see Vernon's year-round climate.

Daytime high
20°
4th warmest
Overnight low
11°
9th coldest
Rainfall
44 mm
8.5 wet days
Daylight
12 h 24 min
6:38 AM – 6:59 PM
Cloud cover
64%
3rd clearest
Wind
12 km/h
9th windiest
Solar energy
3.42 kWh/m²
Travel score
6.4
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 22°C in the first days to 19°C by the end.

A typical September day in Vernon reaches about 20°C in the afternoon and slips back to 11°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 16°C and 25°C. Set against its neighbours, September runs about 4°C cooler than August and about 5°C warmer than October.

10°15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12212
22212
32212
42212
52112
62112
72112
82112
92112
102111
112111
122111
132111
142011
152011
162011
172011
182011
192011
202011
212010
221910
231910
241910
251910
261910
271910
281910
291810
301810

How September really feels in Vernon

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.

Vernon weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 12th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 5311.10.98.50.8
Feb / 46101.19.81.2
Mar11° / 5110.50.411.62.8
Apr15° / 5111013.44.2
May18° / 6211.50155.4
Jun21° / 12°5810.2015.96.3
Jul24° / 14°509.1015.67.0
Aug24° / 14°569.2014.26.9
Sep20° / 11°448.5012.46.4
Oct16° / 6210.9010.54.6
Nov10° / 5911.20.28.92.3
Dec / 6812.40.98.11.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 21% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 16% of September, with mostly cloudy or overcast conditions the remaining 63%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
13862
23862
33862
43862
53862
63862
73763
83763
93763
103763
113763
123862
133862
143862
153862
163961
173862
183862
193862
203862
213862
223763
233763
243664
253664
263466
273367
283268
293268
303070

Chance of precipitation in September

Any precipitation

Vernon gets around 44 mm of rain over 8.5 wet days in September, the driest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 29% and peaks near 36% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)
126
226
326
426
526
626
726
827
927
1027
1127
1227
1327
1427
1528
1628
1728
1828
1929
2029
2130
2230
2331
2431
2532
2633
2734
2835
2935
3036

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 72% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
16029101
2622891
3622891
4642781
5642781
6642781
7672670
8672670
9682570
10692560
11702460
12712360
13712360
14732250
15742150
16752140
17762040
18762040
19772030
20772030
21772030
22772120
23772120
24772120
25772120
26762220
27762220
28772120
29772120
30772120

Wind in September

Winds average 12 km/h in September.

Across September, daily wind ranges from about 12 km/h on the calmest days to 13 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
112calm
212calm
312calm
412calm
512calm
612calm
712calm
812light breeze
912light breeze
1012light breeze
1112light breeze
1212light breeze
1312light breeze
1412light breeze
1512light breeze
1612light breeze
1712light breeze
1812light breeze
1912light breeze
2012light breeze
2112light breeze
2212light breeze
2312light breeze
2412light breeze
2512light breeze
2612light breeze
2713light breeze
2813light breeze
2913light breeze
3013light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 18 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 108 minutes over September. Sunrise moves from 6:16 AM to 6:59 AM, and sunset from 7:32 PM to 6:28 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.36:167:32
213.26:177:30
313.26:197:28
413.16:207:26
513.06:217:23
613.06:237:21
712.96:247:19
812.96:267:17
912.86:277:15
1012.76:297:13
1112.76:307:10
1212.66:327:08
1312.56:337:06
1412.56:357:04
1512.46:367:01
1612.46:386:59
1712.36:396:57
1812.26:416:55
1912.26:426:52
2012.16:446:50
2112.06:456:48
2212.06:476:46
2311.96:486:44
2411.96:506:41
2511.86:516:39
2611.76:536:37
2711.76:546:35
2811.66:566:32
2911.66:576:30
3011.56:596:28

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.42 kWh/m².

For context, solar energy here swings from a low near 0.78 kWh/m² to a high of 5.54 kWh/m² in June across the year — September's 3.42 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.0Bright
24.0Moderate
33.9Moderate
43.9Moderate
53.9Moderate
63.8Moderate
73.8Moderate
83.7Moderate
93.7Moderate
103.6Moderate
113.6Moderate
123.6Moderate
133.5Moderate
143.5Moderate
153.5Moderate
163.4Moderate
173.4Moderate
183.3Moderate
193.3Moderate
203.2Moderate
213.2Moderate
223.1Moderate
233.1Moderate
243.0Moderate
253.0Moderate
262.9Moderate
272.9Moderate
282.8Moderate
292.8Moderate
302.7Moderate
Planning a trip in September

Is September a good time to visit Vernon?

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

6.4
Sightseeing
3rd-best month of the year
3.4
Beach & pool
4th-best month of the year

September is a reasonable time to visit Vernon for sightseeing.

What to pack for Vernon in September

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

In September, Vernon sees daytime highs around 20°C and nights near 11°C. Worth packing: rain gear. About 9 days see rain.

rain gear

UV index in Vernon in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 4 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Vernon peaks around August 11 at about 7 (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.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateLowAug 11UV 7Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb2Low
Mar3Moderate
Apr5Moderate
May6High
Jun7High
Jul7High
Aug7High
Sep4Moderate
Oct3Moderate
Nov1Low
Dec1Low

Air quality in Vernon 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 Vernon is worst in April — around 18 µg/m³ PM2.5 (moderate), and holds fairly steady the rest of the year.

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

01020JanFebMarAprMayJunJulAugSepOctNovDecModerateModerateApr 1018 µg/m³Jul 2012 µg/m³
PM2.5 (µg/m³)Level
Jan15Moderate
Feb15Moderate
Mar18Moderate
Apr18Moderate
May15Moderate
Jun14Moderate
Jul12Good
Aug13Moderate
Sep13Moderate
Oct13Moderate
Nov13Moderate
Dec13Moderate
Location & terrain

Where is Vernon?

Vernon sits at 49.1°N, 1.5°E, 29 m above sea level, in France. The nearest listed city is Mantes-la-Jolie, 22 km away.

Topography around Vernon

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

Within 3 km, the terrain around Vernon has only modest variations in elevation — a maximum elevation change of 161 m around an average of 80 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 177 m; within 80 km, significant variations in elevation — a maximum elevation change of 324 m.

The land around Vernon is covered by trees (53%) within 3 km, cropland (45%) and trees (36%) within 16 km, and cropland (50%) and trees (30%) within 80 km.

3 km
161 m
16 km
177 m
80 km
324 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Mantes-la-Jolie 22 km · Mantes-la-Ville 22 km · Limay 23 km · Évreux 24 km · Louviers 26 km · Les Mureaux 34 km · Verneuil-sur-Seine 39 km · Elbeuf 40 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 Vernon (49.0929°, 1.4633°, elevation 29 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. 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).