During what conditions is the difference between ground temperatures and air temperatures usually less?

The correct choice pertains to overcast or cloudy conditions because these weather patterns tend to act as a blanket for the earth's surface, reducing heat loss at night and limiting temperature contrasts between the ground and the air.

On clear and sunny days, the sun heats the ground more effectively than the air above it, leading to a greater difference between ground and air temperatures. In the morning, temperatures can be cooler due to overnight cooling effects, while in the evening, as the sun sets, the ground loses heat more rapidly compared to the slower cooling of the air, resulting in another significant temperature difference.

In contrast, during overcast or cloudy conditions, the clouds reflect some of the outgoing radiation back down, thereby keeping the ground warmer compared to clear skies. This phenomenon results in a smaller temperature gradient, with both ground and air temperatures being more similar. Consequently, under these cloudy conditions, the difference between ground and air temperatures diminishes.