Water is a heat sink so can have warm air rising over it.

Thermals explained as simple as I can.

All things equal, flat land/no wind.

Land has various colors/materials.

Dark colors or masses like water absorb solar heat. Light colors or vegetated (insulated) do not.

Now assuming cold air, or just cooler, air mass in place the warmed surfaces heat the air above and hot air rises.

Now throw in variables of terrain wind and weather and thermals can be fickle but one constant is found most everywhere. Sunrise which usually occurs at the coldest time of day so thermals are most prevalent and likely to be generated after sunrise as the sun heats the ground surface.

The inverse can be true as the sun sets and the ground effect diminishes.

Deer will walk the thermal tunnel on the top 2/3 rds of a hill too. They bed on the leeward side so they can see in front of them down the hill and get the air from behind them. Terrain has a huge effect, just like a rock creates an eddie in the river.