 In a dry state like Wyoming, most rain and snow is good, but did you know that some precipitation is better than others for growing vegetation? The timing of precipitation is what's important. In fact, when the precipitation falls will not only impact how much plants produce, but also what species of plants grow. On many Wyoming range lands, we are concerned with the grass production for livestock grazing. Rain that falls right before and during spring green up of grasses will influence their production the most. Grasses are generally divided into two groups, cool and warm season. Cool season grasses grow in the cool spring, while warm season grasses grow in the early to mid part of summer. If an area is dominated by cool season grasses, you can bet that most of the rains fall in the spring. Areas receiving most of the rain during summer monsoons will typically have warm season grasses. Winter snow typically provides little benefit for grasses because by the time the grasses are growing, the snow is usually soaked too deep into the soil or it's sublimated into the atmosphere. From the University of Wyoming Cooperative Extension Service, I'm Barton Stam exploring the nature of Wyoming.