Meteorological spring began on March 1st, and you could certainly feel it this weekend. Meteorological spring is defined as the months of March, April and May. This period is the transition between the three coldest and three warmest months of the year.
Meteorological spring always begins on March 1. It always ends on May 31. Meteorologists and climatologists prefer this period for spring because it aligns with the annual temperature cycle. This way it is easier to track changes in weather patterns such as rising temperatures, melting snow, and the emergence of seasonal rainfall. This applies to meteorological summer (June, July and August), meteorological autumn (September, October and November), and meteorological winter (December, January and February).
While meteorological seasons are based on climate patterns and the calendar, astronomical spring is based on the earth's tilt and orbit. The vernal equinox that marks the start of astronomical spring, occurs when the sun crosses the equator. The timing of astronomical spring changes slightly each year. this year it begins on March 20.
According to the astronomical calendar, March 1 is still winter. Nearly 3 weeks of March are winter. According to the astronomical calendar, December 1 is still autumn and nearly 3 weeks of December are autumn. However, average temperatures are warmer in March than in December across Montana. With the meteorological seasons, it makes sense that the warmer month of March would be considered spring and the colder December be winter.
