One of the most noticeable changes in spring is the greening of lawns. Grass mostly goes dormant underneath the snowpack in winter. When the snow melts away in spring, it does not immediately turn green and start growing. The grass won't come out of dormancy until the soil warms enough, at least 50 degrees or warmer depending on the type of grass. Another factor is moisture in the topsoil. Rain can be sporadic this time of year and the soil can be fully saturated or as dry as dust. If the soil is very dry, then the grass won't turn green or grow until it rains enough.
There is a myth that grass requires lightning to turn green. This myth is founded on the concept that certain nutrients are added to the soil by lightning strikes. While true in principal, lightning does not add enough of anything to the soil to make a difference.