Hour, a unit for measuring time, defined as either 1/24 of a day or 3600 seconds (60 minutes). Used alone, the word hour refers to clock time, a composite of mean solar time and atomic time. There are other types of hours, such as sidereal hours (9.83 seconds shorter than clock-time hours), but these are primarily of theoretical interest. Scientists, who are most concerned with precise time intervals, tend to use decimal fractions of the various types of days and multiples of seconds instead of hours. (Seconds and days are based on measurable physical phenomena; the hour is derived from seconds and days.)
Chinook, the American name for a warm, dry wind that blows down a mountainside.
We hear about humidity in just about every weather report on the nightly news. There are several different ways meteorologists measure humidity, but relative humidity is the most common measurement. What is relative humidity, though? Find out in this