Dew point is the most honest measure of "sticky" weather. It's the temperature at which air becomes saturated with moisture. Unlike relative humidity, dew point doesn't change with temperature — making it far more reliable for comparing comfort across climates.
The two humidity metrics
- Dew point — Above 18°C feels muggy. Above 21°C feels oppressive. Below 10°C feels dry. This is the metric we weight most heavily for comfort scoring.
- Relative humidity — The familiar percentage. Useful but misleading: 70% humidity at 15°C feels fine, 70% at 35°C is unbearable. We show it because people expect it, but dew point drives the scoring.
Why it matters
Humidity determines whether you can comfortably eat outdoors, exercise, or sleep with windows open. Two cities at the same temperature can feel completely different based on moisture levels. Coastal Mediterranean cities are typically drier than Southeast Asian cities at the same latitude.
What it doesn't capture
- Indoor humidity depends on building ventilation and air conditioning, which vary widely and aren't measurable from satellite data.
See it in action
The Climate Lab on every city page shows both dew point and relative humidity month by month.