So last year the most popular search in Canada on March 21st was "when was the first day of spring?" Many were surprised to find out it was the day before.The same is true in 2017. The first day of spring in the Northern Hemisphere is Monday, March 20, 2017 at 6:29 am. The spring equinox marks the beginning of spring in the north and the arrival of fall in the Southern Hemisphere. The first week of spring is one of the most popular weekends for new home buying, so we want our readers to know what day that is. Equinox marks the moment there is exactly the same amount of day as night. The name equinox comes from the Latin words â€œequal nightâ€ â€” aequus and nox. The Vernal Equinox is where the sun crosses the equator on its way north. For the Northern Hemisphere, the days will be longer than nights until September.