Orlando, FLA. – It is time to turn your calendar to September, which also happens to be the official start of meteorological fall!
Some might say, fall doesn’t begin for a few weeks but for meteorologists, fall has officially arrived.
What is the difference between meteorological and astronomical seasons?
Climatologists and meteorologists break down the four seasons into groups of three months based on the annual temperatures. The coldest months of December, January and February make up meteorological winter, whereas the hottest months of June, July and August make up the hottest months during meteorological summer. Each season starts the first of the month and ends at the end of the third month. For example, summer begins June 1 and ends Aug. 31.
Astronomical seasons, which most people are used to hearing about, are based on the sun’s position in the sky. This means summer and winter season begins when the sun passes the farthest point north of the equator or at its solstice. And spring and fall begin when the sun is exactly above the equator, meaning equal hours of daytime and nighttime.
Why do meteorologists use different dates?
According to the National Oceanic Atmospheric Administration, weather observations and forecasting led to the creation of these seasons, which are closely tied to our monthly civil calendar compared to astronomical seasons. Having a more consistent length of seasons makes it much easier to calculate season statistics that are very useful for those who depend on weather forecasts, like agriculture and commerce.
How much do the start dates differ?
Seasonal start dates can fluctuate between the 20-22 every three months and include time of day, where meteorological season starts remain consistently the first of every third month. Below is an example of 2021 seasons.
- Summer Solstice: June 20 at 11:32 p.m.
- Meteorological Summer: June 1
- Autumnal Equinox: Sept. 22 at 3:21 p.m.
- Meteorological Fall: Sept. 1
- Winter Solstice: Dec. 21 at 10:59 a.m.
- Meteorological Winter: Dec. 1