Reference Data in Istanbul 11 indicators covering reference data for Istanbul. IndicatorLatest Year10-yr change Rank Cooling and heating degree days - Cities and FUAs — Cooling degree 269.54 Degree days 2025 down 1.8% 425th Cooling and heating degree days - Cities and FUAs — Change in cooling 72.11 Degree days 2025 down 6.6% 248th Cooling and heating degree days - Cities and FUAs 1,016 Degree days 2025 down 15.4% 882nd Cooling and heating degree days - Cities and FUAs — Change in heating -311.25 Degree days 2025 down 147.2% 639th Precipitation - Cities and FUAs — Extreme precipitation days 3.52 Days per year 2024 down 0.9% 917th Precipitation - Cities and FUAs — Change in extreme precipitation -1.11 Days per year 2024 down 3.1% 1106th Dependency ratio - Cities and FUAs 11.6 Percentage of population aged 15-64 years 2024 up 38.1% 1168th Wind threats - Cities and FUAs — Exposure to wind threats 0 Percentage of area 2023 — 273rd Coastal flooding - Cities and FUAs — Built-up area exposure to 0.0405 Percentage of built-up area 2022 up 33.7% 210th Internet speed - Cities and FUAs — Downloading speed 34.5 Percentage of national value 2025 up 143.0% 57th Internet speed - Cities and FUAs — Uploading speed 67.5 Percentage of national value 2025 up 338.3% 23rd