Calais weather in September

In September, Calais sees average daytime highs of 18°C and overnight lows near 14°C, with 68 mm of rain across 11.2 wet days and about 12.4 hours of daylight. It is the 3rd-warmest and 5th-wettest month of the year here.

Highs ease over the month, from about 18°C in the first days to 17°C by the end. The sky is clear or mostly clear about 22% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 24 min at the start of September to 11 h 30 min by month's end. Set against the rest of the year, September is Calais's 6th-clearest and 7th-windiest month. For the whole year in context, see Calais's year-round climate.

Daytime high
18°
3rd warmest
Overnight low
14°
10th coldest
Rainfall
68 mm
11.2 wet days
Daylight
12 h 24 min
6:35 AM – 6:58 PM
Cloud cover
63%
6th clearest
Wind
21 km/h
7th windiest
Solar energy
3.31 kWh/m²
Travel score
5.5
out of 10

Calais is commune in Pas-de-Calais, France.

Air quality
Moderate
PM2.5 10.2 µg/m³ · 2019
Density
2,222/km²
people per km²

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 18°C in the first days to 17°C by the end.

A typical September day in Calais reaches about 18°C in the afternoon and slips back to 14°C overnight — a 3°C spread between the day's warmth and the night's chill. On most days the high lands between 15°C and 20°C. Set against its neighbours, September runs about 2°C cooler than August and about 3°C warmer than October.

10°15°20°25°151015202530
Avg high (°C)Avg low (°C)
11915
21815
31815
41815
51815
61815
71815
81815
91815
101815
111815
121815
131815
141815
151815
161814
171814
181714
191714
201714
211714
221714
231714
241714
251714
261714
271714
281714
291713
301613

How September really feels in Calais

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.

Calais weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 5th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 7914.30.88.21.0
Feb / 6011.419.71.0
Mar / 5110.50.511.51.7
Apr11° / 459.3013.52.7
May14° / 10°519.8015.33.9
Jun16° / 13°498.7016.25.2
Jul19° / 15°519.6015.86.1
Aug19° / 16°6510014.36.2
Sep18° / 14°6811.2012.45.5
Oct15° / 12°9614.3010.43.9
Nov11° / 10116.40.28.72.3
Dec / 94150.77.81.4

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 22% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 20% of September, with mostly cloudy or overcast conditions the remaining 58%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14555
24456
34456
44555
54555
64357
74357
84456
94456
104357
114357
124357
134357
144357
154258
164357
174258
184258
194258
204258
214258
224258
234258
244258
254159
264159
274060
283961
293961
303862

Chance of precipitation in September

Any precipitation

Calais gets around 68 mm of rain over 11.2 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 38% and peaks near 45% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
132
232
332
432
533
633
734
835
935
1036
1136
1236
1337
1437
1537
1638
1738
1839
1939
2040
2140
2240
2341
2441
2542
2643
2743
2844
2945
3045

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 58% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)
1434017
2443917
3463816
4473616
5493616
6503516
7513415
8523315
9533215
10543214
11553114
12563113
13573112
14593011
15603010
16603010
1761309
1862308
1963307
2063316
2163316
2264315
2364324
2464324
2565323
2665323
2767312
2867312
2968302
3069301

Wind in September

Winds average 21 km/h in September.

Across September, daily wind ranges from about 21 km/h on the calmest days to 22 km/h at its breeziest. It stays fairly steady from day to day.

0510152025151015202530
Wind speed (km/h)Feels
121breezy
221breezy
321breezy
421breezy
521breezy
621breezy
721breezy
821breezy
922breezy
1022breezy
1122breezy
1222breezy
1322breezy
1422breezy
1522breezy
1622breezy
1722breezy
1822breezy
1922breezy
2022breezy
2122breezy
2222breezy
2322breezy
2422breezy
2522breezy
2622breezy
2722breezy
2822breezy
2922breezy
3022breezy

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 24 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 114 minutes over September. Sunrise moves from 6:11 AM to 6:58 AM, and sunset from 7:33 PM to 6:25 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.46:117:33
213.36:137:31
313.26:157:29
413.26:167:26
513.16:187:24
613.06:197:22
713.06:217:19
812.96:237:17
912.86:247:15
1012.86:267:12
1112.76:277:10
1212.66:297:08
1312.66:317:05
1412.56:327:03
1512.46:347:01
1612.46:356:58
1712.36:376:56
1812.26:396:54
1912.26:406:51
2012.16:426:49
2112.06:446:47
2212.06:456:44
2311.96:476:42
2411.96:486:39
2511.86:506:37
2611.76:526:35
2711.76:536:32
2811.66:556:30
2911.56:576:28
3011.56:586:25

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.31 kWh/m².

For context, solar energy here swings from a low near 0.68 kWh/m² to a high of 5.74 kWh/m² in June across the year — September's 3.31 kWh/m² falls in the middle.

01234151015202530
Solar energy (kWh/m²)Level
14.0Moderate
23.9Moderate
33.9Moderate
43.8Moderate
53.8Moderate
63.7Moderate
73.7Moderate
83.6Moderate
93.6Moderate
103.5Moderate
113.5Moderate
123.5Moderate
133.4Moderate
143.4Moderate
153.3Moderate
163.3Moderate
173.2Moderate
183.2Moderate
193.1Moderate
203.1Moderate
213.0Moderate
223.0Moderate
233.0Moderate
242.9Moderate
252.8Moderate
262.8Moderate
272.7Moderate
282.7Moderate
292.6Moderate
302.6Moderate
Planning a trip in September

Is September a good time to visit Calais?

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

5.5
Sightseeing
3rd-best month of the year
1.6
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Calais for sightseeing.

What to pack for Calais in September

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

In September, Calais sees daytime highs around 18°C and nights near 14°C. Worth packing: rain gear and a windbreaker. About 11 days see rain.

rain geara windbreaker

Sea temperature near Calais in September

The nearest coast averages about 17°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 18°C and coldest in March near 8°C.

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

5°10°15°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°C)Comfort
Jan9Bracing
Feb8Bracing
Mar8Bracing
Apr9Bracing
May11Bracing
Jun14Bracing
Jul16Cool
Aug18Cool
Sep17Cool
Oct16Cool
Nov13Bracing
Dec11Bracing

UV index in Calais 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 Calais peaks around June 22 at about 6 (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 6 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateLowJun 22UV 6Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb1Low
Mar3Moderate
Apr4Moderate
May6High
Jun7High
Jul6High
Aug7High
Sep4Moderate
Oct2Moderate
Nov1Low
Dec1Low
Location & terrain

Where is Calais?

Calais sits at 51.0°N, 1.9°E, 6 m above sea level, in France. The nearest listed city is Boulogne-sur-Mer, 30 km away.

Topography around Calais

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

Within 3 km, the terrain around Calais has only modest variations in elevation — a maximum elevation change of 20 m around an average of 3 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 250 m; within 80 km, significant variations in elevation — a maximum elevation change of 290 m.

The land around Calais is covered by artificial surfaces (48%) and grassland (23%) within 3 km, water (45%) and cropland (30%) within 16 km, and water (47%) and cropland (30%) within 80 km.

3 km
20 m
16 km
250 m
80 km
290 m
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
September weather nearby: Boulogne-sur-Mer 30 km · Grande-Synthe 32 km · Outreau 33 km · Saint-Pol-sur-Mer 35 km · Saint-Omer 36 km · Dunkirk 38 km · Coudekerque-Branche 38 km · Dover 43 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 Calais (50.9519°, 1.8563°, elevation 6 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).