Reference Data in Boulogne-sur-Mer 12 indicators covering reference data for Boulogne-sur-Mer. IndicatorLatest Year10-yr change Rank Cooling and heating degree days - Cities and FUAs — Cooling degree 4.78 Degree days 2025 down 75.7% 1149th Cooling and heating degree days - Cities and FUAs — Change in cooling -11.59 Degree days 2025 down 447.8% 730th Cooling and heating degree days - Cities and FUAs 1,510 Degree days 2025 down 7.4% 682nd Cooling and heating degree days - Cities and FUAs — Change in heating -365.41 Degree days 2025 down 49.6% 747th Precipitation - Cities and FUAs — Extreme precipitation days 5 Days per year 2024 up 100.0% 745th Precipitation - Cities and FUAs — Change in extreme precipitation 2.68 Days per year 2024 up 1,363.6% 366th Dependency ratio - Cities and FUAs 33.4 Percentage of population aged 15-64 years 2022 up 37.4% 401st Wind threats - Cities and FUAs — Exposure to wind threats 100 Percentage of area 2023 unchanged 1st Coastal flooding - Cities and FUAs — Built-up area exposure to 0.9549 Percentage of built-up area 2022 up 30.3% 111th Main mode of transport to work - Cities and FUAs — Employed persons 25,771 Persons 2022 up 7.2% 275th Internet speed - Cities and FUAs — Downloading speed 17.2 Percentage of national value 2025 down 57.0% 266th Internet speed - Cities and FUAs — Uploading speed 15.1 Percentage of national value 2025 down 70.7% 390th