Meteorology · Humidity — Dewpoint Depression
A small dewpoint depression (air temperature close to the dewpoint) indicates:
- AFalling air pressure
- BVery dry air
- CCertain clear skies
- DHigh relative humidity, with fog or low cloud likely✓ Correct
Explanation
When the air temperature and dewpoint are nearly equal (small depression), the air is near saturation — relative humidity is high and fog, mist, or low stratus can form, especially if the air cools further. A large depression indicates dry air and a lower chance of fog.
Authority: WMO; Bowditch (Pub. No. 9)
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