Spring equinox is Friday, bringing longer days and later sunsets to western WA

Say goodbye to winter! The spring equinox is on Friday, March 20, officially at 7:46 a.m. Pacific Time, and highlights the start of the spring season.

Given the Earth’s 23.5-degree tilt as it rotates around the sun annually, that moment Friday morning will be when the Earth’s axis has no tilt toward or away from the sun. If standing on the equator during an equinox, the sun would pass directly overhead. In addition, both the spring and fall equinoxes are the only times of the year when the sun rises directly from due east and sets due west.

Since the winter solstice back in late December, each day has been getting longer. This is the peak time of year when each day is gaining about 3 and a half minutes per day. The length of each day in western Washington just crossed 12 hours of daylight earlier this week.

The region’s first 7:30 p.m. sunset will be on March 25.

This pace will now gradually slow as the calendar rolls into April and May, reaching the summer solstice in late June with close to 16 hours of daylight.

Spring equinox celebrations date back centuries

Many ancient cultures celebrated the spring equinox, also called the vernal equinox. For instance, at Stonehenge in England, people would gather to watch the sun rise on the equinox and welcome spring. Other cultures, such as the Mayans in Mexico, the Persians, and the Japanese, all had celebrations for the start of spring.

Locally, plants and trees are responding to the longer days and milder temperatures. The cherry blossoms on the University of Washington campus are expected to reach their peak in the coming days. Daffodils and other bulbs are rising out of the ground. The equinox marks the start of the spring season as the landscape emerges with color in the coming weeks and months.

If you have not heard, La Niña has ended and transitioned to “neutral” conditions, meaning sea surface temperatures in the eastern Pacific tropical waters west of Peru are close to average.

The seasonal weather outlook for spring from the National Weather Service’s Climate Prediction Center shows equal chances of above, near, or below average temperatures and precipitation. The outlook for summer reflects warmer than average temperatures and odds tipped toward drier than average conditions – continuing a trend so far this century.

In the short term, rain is forecast in western Washington at times through Friday. So as the calendar rolls over for the start of spring, rain is expected before a drying trend this weekend.

Ted Buehner is the KIRO Newsradio meteorologist. Follow him on X and Bluesky. Read more of his stories here.