Surface Temperature

Surface temperature, measured at ground level (0cm depth), represents the actual temperature of the earth's surface rather than the surrounding air, making it essential for predicting frost formation, ground fog, and the temperature inversions that trap mist in valleys. Unlike air temperature measured at 2 meters, surface temperature responds more rapidly to radiational cooling and heating, often differing from air temperature by 2-5°C or more.

On clear nights with light winds, the ground radiates heat to space faster than air can replenish it, causing surface temperatures to plummet below air temperature and below the dew point, forming frost on vegetation and ground fog in low areas. This temperature differential drives the stunning visual phenomenon of mist layers at dawn, where cold surface air laden with condensation sits below warmer clear air above. For frost photographers, surface temperature below 0°C combined with positive air temperature creates ideal hoar frost conditions without excessive ice buildup.

Landscape photographers targeting fog-filled valleys monitor surface temperature trends to predict when valley floors will cool below the dew point while ridges remain clear, creating those dramatic fog inversion scenes. Surface temperature also affects wildlife behavior, particularly reptiles and insects that depend on ground warmth for activity. PhotoWeather tracks surface temperature in relation to air temperature and dew point to predict frost windows, forecast ground fog formation, and alert photographers to temperature inversion opportunities that create layered atmospheric effects. Understanding the surface-to-air temperature gradient helps photographers anticipate exactly where and when fog will form in complex terrain, choosing viewpoints that look down into fog-filled valleys from clear ridges above. Typical surface temperatures range from 5°C below to 15°C above air temperature depending on surface type, solar exposure, wind speed, and cloud cover.