California will mark a seasonal turning point on March 20 as the March equinox arrives, bringing longer days, later sunsets, and the gradual transition toward warmer spring weather.
This year, the March equinox will occur on March 20, marking the beginning of astronomical spring across the US and the Northern Hemisphere.
People will notice the seasonal shift as daylight gradually extends later into the evening and the Sun appears higher in the sky in the weeks ahead. These changes mark the transition from winter toward the brighter and warmer months of spring.
The Californians will experience the March equinox at 7:46 a.m. Pacific Time on Friday, March 20, 2026, according to the National Weather Service (NWS).
What is March Equinox?
An equinox occurs twice each year, in March and September, when the center of the Sun crosses the plane of Earth’s equator.
According to NASA, the equinox is the moment when Earth reaches a specific point in its orbit around the Sun, allowing sunlight to fall nearly evenly across both hemispheres.
NASA says that at this moment, neither the Northern Hemisphere nor the Southern Hemisphere is tilted toward or away from the Sun. As a result, sunlight reaches both halves of Earth in a nearly even way.
The word “equinox” comes from the Latin words “aequus,” meaning equal, and “nox,” meaning night, reflecting that daylight and darkness are nearly equal around the world at this time of year.
The NWS notes that the March event is also called the vernal equinox, referring to the start of spring in the Northern Hemisphere. It is sometimes called the northward equinox because the Sun’s apparent path in the sky begins moving north after this date.
Why Does This Happen?
Earth experiences seasons because its axis is tilted about 23.5 degrees relative to its orbit around the Sun, according to Griffith Observatory. This tilt causes different parts of the planet to receive varying amounts of sunlight throughout the year.
Earth experiences seasons because its axis is tilted. The planet’s axis leans about 23.5 degrees relative to its orbit around the Sun, as per Griffith Observatory. This tilt means that different parts of Earth receive varying amounts of sunlight throughout the year.
As Earth travels around the Sun, the angle at which sunlight reaches each hemisphere changes. During the March equinox, the planet’s tilt is positioned so that neither hemisphere leans toward the Sun.
After the equinox passes, the Northern Hemisphere gradually tilts toward the Sun, bringing more direct sunlight and steadily increasing daylight hours each day. This pattern continues until the June solstice, the longest day of the year in the Northern Hemisphere.
This pattern continues until the June solstice, which marks the longest day of the year in the Northern Hemisphere.
NASA notes that the seasonal cycle follows a consistent pattern each year:
- March equinox: Beginning of spring
- June solstice: Beginning of summer
- September equinox: Beginning of fall
- December solstice: Beginning of winter
What Will Californians Experience?
Following the March equinox, Californians will begin noticing clear signs of the seasonal shift as daylight hours grow longer each day, with earlier sunrises and later sunsets.
The Sun will also appear higher in the afternoon sky, allowing more sunlight to reach the ground and gradually raising temperatures as spring progresses.
Across California, the transition into spring often brings shifting weather patterns and the early stages of seasonal plant growth.
In 2024, the first day of spring fell on March 19, which was the earliest spring equinox in 128 years, according to the Farmer’s Almanac.
Are Day and Night Really Equal?
Although the equinox is often associated with equal day and night, the two are not the same length.
One reason is atmospheric refraction, which bends sunlight as it passes through Earth’s atmosphere. This bending causes the Sun to appear slightly above the horizon even when it is technically below it.
Another factor involves the way sunrise and sunset are defined. These measurements are based on the moment the upper edge of the Sun appears or disappears at the horizon, rather than the exact center of the Sun.
Because of these factors, daylight on the equinox lasts slightly longer than 12 hours.
The difference also varies depending on latitude. Near the equator, daylight lasts about 12 hours and six minutes, according to NWS. At mid-latitudes similar to California’s location, the day is slightly longer than that.
As a result, the day when daylight and nighttime are exactly 12 hours long typically occurs a few days before or after the equinox.
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