Grande-Synthe in Fall
In fall (September, October and November), Grande-Synthe sees average daytime highs around 15°C and overnight lows near 10°C, with 184 mm of precipitation over about 35 wet days across the season. It is the 2nd-warmest season and the wettest season of the year.
Over the season highs ease from about 20°C in early September to 9°C by late November. The sky is clear or mostly clear about 15% of the time across fall, and the air most often feels dry.
Fall is Grande-Synthe's 2nd-best season to visit on our travel score. For the whole year in context, see Grande-Synthe's year-round climate.
- Avg daytime high
- 15°C
- 2nd-warmest season
- Avg overnight low
- 10°C
- Precipitation
- 184 mm
- 35 wet days
- Avg wind
- 16 km/h
- Travel score
- 4.1
- 2nd-best season
- Months
- Sep · Oct · Nov
Temperature in Grande-Synthe in Fall
Over the season highs ease from about 20°C in early September to 9°C by late November.
A typical fall day in Grande-Synthe reaches about 15°C and drops to 10°C overnight. The warmest of the three months is September, the coolest November.
How fall really feels in Grande-Synthe
Once humidity and wind are folded in, fall brings about 0 days that feel above 32°C and 0 that feel at or below 0°C.
fall sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.
Grande-Synthe weather by month
How the three fall months (September, October and November) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 7° / 3° | 56 | 11.8 | 0.9 | 8.2 | 0.9 |
| Feb | 8° / 3° | 47 | 10 | 0.8 | 9.6 | 1.1 |
| Mar | 10° / 5° | 46 | 10.6 | 0.5 | 11.5 | 2.3 |
| Apr | 13° / 7° | 44 | 10.2 | 0.1 | 13.5 | 3.7 |
| May | 16° / 10° | 54 | 10.7 | 0 | 15.3 | 5.1 |
| Jun | 19° / 12° | 54 | 9.9 | 0 | 16.2 | 6.0 |
| Jul | 22° / 15° | 54 | 10.5 | 0 | 15.8 | 6.5 |
| Aug | 22° / 15° | 63 | 10.5 | 0 | 14.3 | 6.5 |
| Sep | 19° / 13° | 55 | 9.8 | 0 | 12.4 | 5.9 |
| Oct | 15° / 10° | 65 | 11.9 | 0 | 10.4 | 4.2 |
| Nov | 11° / 6° | 65 | 12.8 | 0.3 | 8.7 | 2.3 |
| Dec | 8° / 4° | 68 | 12.5 | 0.8 | 7.8 | 1.1 |
Cloud cover in Fall
The sky is clear or mostly clear about 15% of the time across fall.
Chance of precipitation in Fall
Grande-Synthe gets around 184 mm of rain and snow over 35 wet days across fall. The line is the day-by-day chance of measurable precipitation.
Humidity in Fall
Most of fall feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Fall
Winds average 16 km/h across fall.
Sunrise & sunset in Fall
Daylight runs from about 13 h 24 min in early September to 8 h 06 min by late November. The lit band spans sunrise to sunset each day.
Solar energy in Fall
Average shortwave solar energy reaching the ground each day across fall, about 2.1 kWh/m².
Is fall a good time to visit Grande-Synthe?
Our two travel scores rate fall for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
fall is a reasonable time to visit Grande-Synthe for sightseeing.
What to pack for Grande-Synthe in Fall
From fall's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In fall, Grande-Synthe sees daytime highs around 15°C and nights near 10°C. Pack a warm layer. Worth having: rain gear. About 35 days see rain.
Sea temperature near Grande-Synthe in Fall
The nearest coast averages about 15°C across fall — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 13 km away) is warmest in August at about 18°C and coldest in February near 7°C.
The water stays below 20°C all year — cool enough that most swimmers want a wetsuit.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 8 | 7 | 7 | 9 | 12 | 15 | 17 | 18 | 18 | 15 | 13 | 10 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Cool | Cool | Cool | Cool | Bracing | Bracing |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 8 | Bracing |
| Feb | 7 | Bracing |
| Mar | 7 | Bracing |
| Apr | 9 | Bracing |
| May | 12 | Bracing |
| Jun | 15 | Bracing |
| Jul | 17 | Cool |
| Aug | 18 | Cool |
| Sep | 18 | Cool |
| Oct | 15 | Cool |
| Nov | 13 | Bracing |
| Dec | 10 | Bracing |
UV index in Grande-Synthe in Fall
Clear-sky midday UV across fall averages around 2. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Grande-Synthe 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.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 1 | 1 | 3 | 4 | 6 | 6 | 6 | 6 | 4 | 2 | 1 | 1 |
| Level | Low | Low | Moderate | Moderate | High | High | High | High | Moderate | Moderate | Low | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 1 | Low |
| Feb | 1 | Low |
| Mar | 3 | Moderate |
| Apr | 4 | Moderate |
| May | 6 | High |
| Jun | 6 | High |
| Jul | 6 | High |
| Aug | 6 | High |
| Sep | 4 | Moderate |
| Oct | 2 | Moderate |
| Nov | 1 | Low |
| Dec | 1 | Low |
Where is Grande-Synthe?
Grande-Synthe sits at 51.0°N, 2.3°E, 2 m above sea level, in France. The nearest listed city is Saint-Pol-sur-Mer, 3.0 km away.
Topography around Grande-Synthe
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Grande-Synthe.
Within 3 km, the terrain around Grande-Synthe has only modest variations in elevation — a maximum elevation change of 42 m around an average of 5 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 52 m; within 80 km, significant variations in elevation — a maximum elevation change of 290 m.
The land around Grande-Synthe is covered by artificial surfaces (50%) and trees (22%) within 3 km, water (39%) and cropland (37%) within 16 km, and water (38%) and cropland (34%) within 80 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
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 Grande-Synthe (51.0154°, 2.2997°, elevation 2 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.