Boulogne-sur-Mer weather in May

In May, Boulogne-sur-Mer sees average daytime highs of 14°C and overnight lows near 10°C, with 57 mm of rain across 10.7 wet days and about 15.2 hours of daylight. It is the 6th-warmest and 8th-wettest month of the year here.

Highs climb over the month, from about 13°C in the first days to 16°C by the end. The sky is clear or mostly clear about 25% of the time in May, and the air most often feels dry.

Daylight stretches from about 14 h 30 min at the start of May to 15 h 54 min by month's end. Set against the rest of the year, May is Boulogne-sur-Mer's 5th-clearest and 9th-windiest month. For the whole year in context, see Boulogne-sur-Mer's year-round climate.

Daytime high
14°
6th warmest
Overnight low
10°
7th coldest
Rainfall
57 mm
10.7 wet days
Daylight
15 h 18 min
5:12 AM – 8:28 PM
Cloud cover
63%
5th clearest
Wind
19 km/h
9th windiest
Solar energy
5.47 kWh/m²
Travel score
4.2
out of 10
Air quality
Moderate
PM2.5 11.8 µg/m³ · 2019

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 13°C in the first days to 16°C by the end.

A typical May day in Boulogne-sur-Mer reaches about 14°C in the afternoon and slips back to 10°C overnight — a 5°C spread between the day's warmth and the night's chill. On most days the high lands between 11°C and 19°C. Set against its neighbours, May runs about 3°C warmer than April and about 3°C cooler than June.

10°15°20°151015202531
Avg high (°C)Avg low (°C)
1139
2139
3139
4139
5139
6149
7149
8149
9149
10149
11149
121410
131410
141410
151410
161410
171510
181510
191510
201510
211510
221511
231511
241511
251511
261511
271611
281611
291611
301611
311611

How May really feels in Boulogne-sur-Mer

Once humidity and wind are folded in, May 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

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

Boulogne-sur-Mer weather by month

How May compares with the rest of the year at a glance. May is the 6th-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 8814.30.98.20.9
Feb / 6411.60.99.71.0
Mar / 5310.80.511.51.9
Apr12° / 4810.1013.53.0
May14° / 10°5710.7015.24.2
Jun17° / 13°529.5016.25.5
Jul19° / 15°5510.2015.86.2
Aug20° / 15°7010.4014.36.2
Sep18° / 13°6911.2012.45.5
Oct15° / 11°10114.3010.43.9
Nov11° / 10715.90.18.72.2
Dec / 10614.70.77.81.3

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 25% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 17% of May, with mostly cloudy or overcast conditions the remaining 59%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13961
23961
33961
43862
53961
64060
74060
84060
94060
104159
114159
124159
134159
144159
154159
164258
174258
184357
194357
204357
214357
224357
234357
244357
254258
264258
274258
284258
294258
304159
314159

Chance of precipitation in May

Any precipitation

Boulogne-sur-Mer gets around 57 mm of rain over 10.7 wet days in May. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 36% and peaks near 37% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
137
237
336
436
536
635
735
835
935
1035
1135
1235
1335
1436
1536
1636
1736
1836
1936
2036
2136
2236
2336
2435
2535
2635
2735
2835
2935
3035
3135

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

Most of May feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, May lands in the dry band about 94% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)
19910
29910
39820
49820
59730
69730
79640
89640
99640
109640
119550
129550
139550
149550
159550
169550
179550
189460
199460
209460
219370
229370
239280
249280
259190
2690100
2789110
2888120
2987121
3086131
3185141

Wind in May

Winds average 19 km/h in May.

Across May, daily wind ranges from about 18 km/h on the calmest days to 19 km/h at its breeziest. It stays fairly steady from day to day.

0510152025151015202531
Wind speed (km/h)Feels
119light breeze
219light breeze
319light breeze
419light breeze
519light breeze
619light breeze
719light breeze
819light breeze
919light breeze
1019light breeze
1119light breeze
1219light breeze
1319light breeze
1419light breeze
1519light breeze
1619light breeze
1719light breeze
1819light breeze
1919light breeze
2018light breeze
2118light breeze
2218light breeze
2318light breeze
2418light breeze
2518light breeze
2618light breeze
2718light breeze
2818light breeze
2918light breeze
3018light breeze
3118light breeze

Sunrise & sunset in May

DaylightNight

Daylight runs from about 14 h 30 min at the start of May to 15 h 54 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 84 minutes over May. Sunrise moves from 5:37 AM to 4:54 AM, and sunset from 8:04 PM to 8:47 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.55:378:04
214.55:358:06
314.65:338:08
414.65:318:09
514.75:308:11
614.75:288:12
714.85:268:14
814.95:248:16
914.95:238:17
1015.05:218:19
1115.05:198:20
1215.15:188:22
1315.15:168:23
1415.25:158:25
1515.25:138:26
1615.35:128:28
1715.35:108:29
1815.45:098:31
1915.45:088:32
2015.55:068:33
2115.55:058:35
2215.55:048:36
2315.65:038:38
2415.65:018:39
2515.75:008:40
2615.74:598:41
2715.74:588:43
2815.84:578:44
2915.84:568:45
3015.84:558:46
3115.94:548:47

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.47 kWh/m².

For context, solar energy here swings from a low near 0.71 kWh/m² to a high of 5.83 kWh/m² in June across the year — May's 5.47 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.1Bright
25.1Bright
35.1Bright
45.1Bright
55.2Bright
65.2Bright
75.2Bright
85.3Bright
95.3Bright
105.3Bright
115.3Bright
125.4Bright
135.4Bright
145.4Bright
155.4Bright
165.5Bright
175.5Bright
185.5Bright
195.5Bright
205.5Bright
215.6Bright
225.6Bright
235.6Bright
245.6Bright
255.6Bright
265.6Bright
275.6Bright
285.6Bright
295.7Bright
305.7Bright
315.7Bright
Planning a trip in May

Is May a good time to visit Boulogne-sur-Mer?

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

4.2
Sightseeing
5th-best month of the year
0.1
Beach & pool
6th-best month of the year

May is a reasonable time to visit Boulogne-sur-Mer for sightseeing.

What to pack for Boulogne-sur-Mer in May

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

In May, Boulogne-sur-Mer sees daytime highs around 14°C and nights near 10°C. Worth packing: a warm layer, rain gear and sun protection. About 11 days see rain.

a warm layerrain gearsun protection

Sea temperature near Boulogne-sur-Mer in May

The nearest coast averages about 11°C in May — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea offshore is warmest in August at about 18°C and coldest in February near 8°C.

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

5°10°15°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshing
Sea temperature (°C)Comfort
Jan9Bracing
Feb8Bracing
Mar8Bracing
Apr9Bracing
May11Bracing
Jun14Bracing
Jul16Cool
Aug18Cool
Sep18Cool
Oct16Cool
Nov13Bracing
Dec11Bracing

UV index in Boulogne-sur-Mer in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Boulogne-sur-Mer peaks around June 20 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 20UV 6Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb1Low
Mar3Moderate
Apr4Moderate
May6High
Jun7High
Jul6High
Aug6High
Sep4Moderate
Oct2Moderate
Nov1Low
Dec1Low
Location & terrain

Where is Boulogne-sur-Mer?

Boulogne-sur-Mer sits at 50.7°N, 1.6°E, 43 m above sea level, in France. The nearest listed city is Outreau, 3.0 km away.

Topography around Boulogne-sur-Mer

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

Within 3 km, the terrain around Boulogne-sur-Mer has only modest variations in elevation — a maximum elevation change of 187 m around an average of 54 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 274 m; within 80 km, significant variations in elevation — a maximum elevation change of 290 m.

The land around Boulogne-sur-Mer is covered by artificial surfaces (34%), trees (23%) and grassland (22%) within 3 km, water (42%) within 16 km, and water (45%) and cropland (31%) within 80 km.

3 km
187 m
16 km
274 m
80 km
290 m
treesgrasslandcroplandartificial surfacesbare terrainwater
May weather nearby: Outreau 3.0 km · Calais 30 km · Berck-Plage 36 km · Berck 36 km · Saint-Omer 46 km · Dover 49 km · Folkestone 51 km · Deal 57 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 Boulogne-sur-Mer (50.7249°, 1.6137°, elevation 43 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).