Spring is coming to the Northern Hemisphere, but how can you tell when it will start? No need to Google the vernal equinox; to work out when the season officially begins, you only need to look at the stars.
The beginning of spring in the Northern Hemisphere and autumn in the Southern Hemisphere is marked by the vernal equinox — the point when Earth's axis is side-on to the sun, spreading light and heat equally around the globe. This year it occurs on March 20.
