- March 1 starts the spring weather.
- This is different from the vernal equinox, which takes place on March 20.
- Weather stations are based on temperatures, not strictly on the position of the sun.
Weather spring arrives on Monday, and although you may be looking forward to warmer weather, you may wonder why this is happening weeks before the vernal equinox.
After a period of record cold and repeated rounds of snow in February, spring could not come early enough for those affected by power and water outages in Texas and neighboring states.
It turns out that spring has arrived, at least according to meteorologists.
The arrival of spring, which you have probably heard of, is known as the vernal equinox.
This is the moment when the most direct rays of the sun are shining on the equator. In 2021, the vernal equinox will take place on Saturday, March 20, at 5:37 am EDT. If you wake up early on a weekend morning, you can see that this year.
Its autumn counterpart, the autumnal equinox, as well as the summer and winter solstices, all occur in late September, June and December, respectively, due to the tilt of the Earth’s axis as it revolves around the sun.
This change in the angle of the sun throughout the year is the reason we have so-called astronomical stations.
(MOST: March temperature perspective)
The orientation of the Earth in relation to the sun at the vernal equinox (spring) of the northern hemisphere, summer solstice, autumn equinox and winter solstice.
(NOAA / NWS)
Why do meteorologists deviate from these seemingly concrete definitions?
Everything has to do with temperatures.
By examining the average high and low daily temperatures throughout the year, you will quickly notice a pattern.
The coldest three months of the year in the Northern Hemisphere are generally from early December to late February, while the warmest three months are typically from early June to late August.
These beautiful and clean three-month buckets are known as winter and summer weather, respectively.
And these three-month clean buckets of temperature do not line up so well with astronomical stations, for example, from late December to late March.
A generic sample trace of the average high (red) and low (blue) daily temperatures during the year. The coldest three months of the year are known as winter weather. The three warmest months are the summer weather. The transition between the two is spring and autumn weather.
(NOAA / NWS)
In fact, Alaskan climatologist Brian Brettschneider, based in Alaska, calculated that the winter weather from December 1 to February 28 is a better fit for the coldest time of the year in most of the United States and Canada.
On a analysis of dozens of US citiesBrettschneider found that only Honolulu, Hawaii, had its 90-day coldest stretch extended until March.
For anyone living in the northern United States, this makes sense.
It seems a little silly when we say that “winter has come” a few days before Christmas, when many parts of the north have already had at least a significant snowfall or cold wave.
The meteorological spring – from March 1st to May 31st – is the transition between the coldest three months and the warmest three months of the year.
Another advantage of weather stations is the ease of calculating seasonal statistics, since every weather station starts on the first day of the month.
A March of increased daylight and temperatures
Most of the United States will get an entire hour of daylight at dusk when daylight saving time arrives on March 14.
Even if there was no daylight saving time, most areas in the northern United States would gain an extra 30-45 minutes of sunlight at night in late March. The southernmost locations would normally only capture an additional 15 to 30 minutes of daylight during the month, if our clocks didn’t work.
Hours of sunset on March 1 (before daylight saving time) and March 31 (after daylight saving time) in 2021 for various U.S. cities.
(Data: NOAA; Table: Infogram)
Although March has a well-deserved storm reputation, including winter storms in the western and northern U.S., with the sun gradually shining higher in the sky, average high temperatures typically rise by about 10 degrees in the midwest, northeast and plains at the end of the month.
(MOST: When to wait for the early 70s and 80s of spring, where you live)
High average daily temperatures on March 1st and 31st in several cities in the USA. The biggest change in temperatures during the month occurs in the northern United States, mainly in the plains and in the midwest.
(Data: NOAA; Table: Infogram)
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