A very bad natural disaster is a drought. A drought is when there is a lack of precipitation (i.e. rain, snow, hail, sleet) over an extended period of time. The length of time is usually a season or more with the result being a water shortage for plants, people or animals.
This article explains Dew. The wetness on a lawn in the morning is dew. Looking at the dew, you often wonder if there was rain overnight.