Meteorologists Say Spring Starts Sunday, And Yes We Know That Is Before The Equinox

Astronomical Vs. Meteorological Spring Explained

If you are anything like me, you don't like winter at all. By February, I am desperate for warmer weather and count the days down to March.

Us meteorologists consider "spring" to start on March 1, a few weeks before the official start of the season, the spring equinox.

Despite my dislike for winter, we meteorologists actually have a real reason for starting early: Our definition of seasons is slightly different.

When Spring Technically Starts

Most people define the beginning of spring as the spring equinox (also called the vernal equinox, for those of you who like official terminology). It is defined as the moment the sun's most direct rays shine on the equator, and it is also when there is "nearly" equal 12 hours of light and darkness for everyone on Earth.

In 2026, the vernal equinox will occur on Friday, March 20, at 10:46 a.m. ET.

The fall equivalent, called the autumnal equinox, occurs in late September. And while we are at it, the summer and winter solstices occur in late June and December, respectively. That's when the sun is closest to the poles.

The reason why we have seasons in the first place is because of the tilt of the Earth. It causes the sun's angle in the sky to change throughout the year, which leads to different amounts of sunlight throughout the year.

What Meteorologists Use To Define Seasons

So why do meteorologists go against the grain here?

One word: temperatures.

For those of us in the Northern Hemisphere (you can generally reverse this in the Southern Hemisphere), the coldest three months of the year are usually December through February.

Contrast that with the warmest three months, which are often June to August. These are known as meteorological winter and summer.

Alaska-based climatologist Brian Brettschneider calculated that the Dec. 1-Feb. 28 meteorological winter is a better fit for the coldest time of year in most of the United States and Canada.

In an analysis of dozens of U.S. cities, Brettschneider found only Honolulu, Hawaii, had its coldest 90-day stretch extend deep into March. For the rest of the cities analyzed, the coldest period ended in late February or early March.

Meteorological seasons tend to match better with what people think of seasons. Think of how Christmas is just days after the winter solstice, but most people view winter through the entire month.

By grouping the seasons by temperature, you’re also grouping the seasons more by common weather patterns. People often think of December as winter even though, technically, most of the month is fall.

So meteorological spring – March 1 through May 31 – is the transition between the three coldest and three warmest months of the year.

Also, calculating the monthly average is easier with meteorological seasons since they start on the first of the month vs the end of the month, like every equinox and solstice.

March Has Large Increase In Daylight And Temperatures

March shows even more factors when you have to take into account daylight saving time on March 8. This is the one where you lose an hour of sleep but also pick up an hour of evening light.

But this is a cool fact. Sunsets move later by about 30 to 45 minutes throughout the month on the higher elevations. For the southern parts of the country, it is just a 15 to 30-minute extension.

While March has a well-earned stormy reputation, including winter storms in the West and northern U.S., with the sun gradually shining higher in the sky, average high temperatures typically rise about 10 degrees in the Midwest, Northeast and Plains by month's end.

Rob Shackelford is a meteorologist and climate scientist at weather.com. He received his undergraduate and master’s degrees from the University of Georgia studying meteorology and experimenting with alternative hurricane forecasting tools.