Spring Time

According to the astronomical definition, Spring begins on the 21st of March and lasts until 20th of June, the vernal equinox in the northern hemisphere. According to this definition, therefore, the traditional mid-summer's day is the first day of summer. The meteorological definition (used in order to express whether 'Spring' has been hot or cold or wet, for example) has Spring starting on the 1st of March, since this more in line with weather conditions thought to be typical of Spring. The phenological definition of Spring relates to the blossoming of a range of plant species. It therefore varies according to the climate (as in 'Spring comes late to the north-east'). Calendars typically give the first, but the second and third are more in line with common use.

Severe weather most often occurs during the spring, when warm air begins to invade from lower latitudes while cold air is still pushing from the polar regions. Flooding is also most common in and near mountainous areas during this time of year because of snowmelt, many times accelerated by warm rains. In the United States, Tornado Alley is most active by far this time of year, especially since the Rocky Mountains prevent the surging hot and cold air masses from spreading eastward and instead force them directly at each other. Besides tornadoes, supercell thunderstorms can also produce dangerously large hail and very high winds, for which a severe thunderstorm warning or tornado warning is usually issued. Even more so than winter, the jet streams play an important role in severe weather in the springtime.

Spring is seen as a time of growth, renewal, of new life (both plant and animal) being born. The term is also used more generally as a metaphor for the start of better times.