First Day of Spring Facts: Is It Arriving Earlier?

Snow melting, flowers blooming earlier in U.S., research shows.

It may not feel like it in the chilly United States, but it's the first day of spring in the Northern Hemisphere.

The season officially begins at 12:57 p.m. ET on March 20—a precise and fixed point in time defined as when the center of the sun passes directly over the Equator. (See "Vernal Equinox Pictures: First-Day-of-Spring Celebrations.")

But biological signs of spring's arrival are a different science, defined by the timing of events—such as the first appearance of flowers—that change from year to year and place to place.

According to a long-term research project done in Colorado's Rocky Mountains, for instance spring in that region now begins, on average, about three weeks earlier than it did in the 1970s.

The project

DON'T MISS THE REST OF THIS STORY!
Create a free account to continue and get unlimited access to hundreds of Nat Geo articles, plus newsletters.

Create your free account to continue reading

No credit card required. Unlimited access to free content.
Or get a Premium Subscription to access the best of Nat Geo - just $19
SUBSCRIBE

Read This Next

Is banning fishing bad for fishermen? Not in this marine reserve
SeaWorld allegedly violated the Animal Welfare Act. Why is it still open?
'World’s worst shipwreck' was bloodier than we thought

Go Further

Subscriber Exclusive Content

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet