Description
What causes dewdrops like those in this macro photo to form? It's all relative, as in relative humidity – the ratio of how much moisture is in the air versus how much it's able to hold at a given temperature. That may sound complex, but think of it this way: when the air is cool (say at night), it can hold less moisture before it's 'full', or has reached the dew point . That moisture has to go somewhere, and a lawnful of grass includes a whole lot of surface area, so that's where a lot of the excess water winds up. As daylight heats the air, it'll be able to take on more moisture through evaporation , putting a damper on the dampness.