Is evaporation faster on a cloudy day?

Does Cloud Cover Affect Evaporation?

It might seem like water disappears into thin air no matter the weather, but the truth is, evaporation doesn’t happen at the same pace every day—and cloud cover plays a big role. On sunny days, the sun’s energy warms the surface of lakes, puddles, and even damp clothes on a line, giving water molecules enough energy to break free and become vapor. This process speeds up when it's warm because the added heat reduces the energy barrier for evaporation.

On cloudy days, however, the story changes. Clouds act like a blanket, blocking a significant portion of sunlight from reaching the ground. With less solar energy available, surface temperatures stay cooler, which slows down the rate at which water evaporates. So even though evaporation can still occur on overcast days, it’s generally much slower compared to clear, sunny conditions.

Temperature and sunlight are key drivers of evaporation, and cloudy days usually bring both lower light levels and cooler temperatures. This double effect means less energy is available to turn liquid water into vapor. That’s why you’ll often notice damp ground lingering after rain on cloudy days, while on sunny days, everything dries up much faster.

Even humidity and wind play supporting roles, but when comparing similar conditions, a sunny day will almost always lead to faster evaporation than a cloudy one. So, next time you’re waiting for the laundry to dry or watching a puddle after a storm, look up at the sky—your answer lies there.