What Will the Weather Be? (Let's-Read-and-Find-Out Science 2, 1)

Meteorologists today know more than ever before. They use weather maps, satellites, balloons, and planes to measure temperature, air pressure, wind direction, and speed. But changes outside are not always predictable, because our weather depends on the air hundreds of miles away. Sometimes meteorologists tell us to take our umbrellas when we don't need them. Other times they say we don't need a jacket when we do. Will it rain? Will it snow? Now even the experts know for sure.