Spring Officially Starts Monday. Pasadena Already Experienced the Equinox Last Week

This year, Monday, March 20 is designated as the ‘vernal equinox,’ marking the official start of the spring season in the Northern Hemisphere. The celestial event occurs when the Earth’s axis is tilted neither towards nor away from the sun, resulting in equal amounts of daylight and nighttime across the globe.

But in Pasadena, the equinox has already come and gone — on March 15, last Wednesday. The sunrise came at 7:01 a.m. and the sunset at 7:01 p.m. Not to worry, scientists say, this is normal because the Earth is not a perfect circle. The actual timing of the spring equinox varies around the globe. 

After the spring equinox, the Northern Hemisphere experiences earlier sunrises, later sunsets, and the emergence of budding plants. In contrast, the Southern Hemisphere will experience later sunrises, earlier sunsets, and the falling of dry leaves.

The first full moon of spring, which will also be a supermoon, is expected to rise during the equinox, making it a rare celestial event. 

Meanwhile, spring 2023 is starting with Southern California awash in a series of drought-busting atmospheric rivers. Two storms are expected during the week, with heavy rain and gusty winds predicted for Tuesday.

Temperatures are far from Spring-like. While the average temperature in Pasadena on the spring equinox is normally around 70, the National Weather Service predicts a high of just 62 on Monday  —  lower than average Pasadena winter daytime temps.