“It was one of those March days when the sun shines hot and the wind blows cold, when it is summer in the light, and winter in the shade.”

~ Charles Dickens, “Great Expectations”

It’s already March! Monday of this week – March 1 – was the first day of meteorological spring –not to be confused with the astronomical spring that begins on March 20. The weather prediction for yesterday included rain and will include a chance next week as well.

Question: Falling between these two dates, is the precipitation considered a “spring shower” or a “late season winter storm”? Whichever it may be, it’s much-needed. But why the discrepancy as to the beginning of the new season?

So, what’s the difference? The short answer: Meteorological spring is based on annual temperature cycles and astronomical spring is based on the position of the Earth in relation to the sun. Now the long answer…

Meteorological season lengths stay the same year-to-year (with the exception of leap year); it also allows the four seasons to be closer in length. According to NOAA, this method of breaking down the seasons leads to a more consistent way in which to compare monthly and seasonal climatological statistics (which are valuable in agriculture, weather forecasting, etc.).

Meteorological Spring: March, April, May
Meteorological Summer: June, July, August
Meteorological Fall: September, October, November
Meteorological Winter: December, January, February

There is a reason the old saying, “In like a lion, out like a lamb” is used to describe March. March often displays a transition from the cold winter to the warm summer; an example could be found this week: on Tuesday it was warm and sunny and on Wednesday was cold and rainy.

The astronomical classification is based on the Earth’s travel around the sun. Within a year’s time we see two equinoxes and two solstices. Essentially, the equinoxes refer to the times of the year when we see equal amounts of daylight and darkness; the sun is directly over the equator. The two solstices refer to the times when the Earth is tilted toward or away from the sun. The summer solstice – the longest day and shortest night of the year – is when the Earth is tilted toward the sun. The winter solstice – the shortest day and longest night of the year – is when the Earth is tilted away from the sun. The variability with the astronomical season length makes it very difficult for climatologists and meteorologists to compare the year-to-year weather statistics. Thus, meteorological spring was born!

So if you want to celebrate spring a little early … it’s happening. Otherwise, spring is right around the corner! As the time for long dog walks draws near, will it be with sunglasses or an umbrella?

Sue Kilpatrick is a Crescenta Valley
resident and Official Skywarn Spotter for the
National Weather Service Reach her at suelkilpatrick@gmail.com.