What relationship would you expect to find between the air temperature and dewpoint rmperature at ground level if the area is covered by fog?

When an area is covered by fog, the air temperature and dew point temperature are typically very close to each other, often within a degree or two. This is because fog forms when the air becomes saturated with moisture, causing the dew point to rise to near the current air temperature. As a result, you would expect to find a minimal difference between the two temperatures in foggy conditions.