The start of spring varies depending on the hemisphere and the calendar system used. In the Northern Hemisphere, spring begins on the spring equinox, which is the day when the sun crosses the celestial equator and day and night are of equal length. The spring equinox usually falls on March 20 or 21.

In the Southern Hemisphere, spring begins on the autumnal equinox, which is the day when the sun crosses the celestial equator and day and night are of equal length. The autumnal equinox usually falls on September 22 or 23.

There are two different calendar systems that are used to track the seasons: the meteorological calendar and the astronomical calendar. The meteorological calendar divides the year into four seasons of three months each. Spring in the meteorological calendar begins on March 1 and ends on May 31.

The astronomical calendar, on the other hand, is based on the Earth's position in relation to the sun. The astronomical seasons are defined by the solstices and equinoxes. The spring equinox marks the beginning of spring in the astronomical calendar.

So, when does spring start? It depends on which calendar system you are using and which hemisphere you are in. But no matter which system you use, spring is a time of new beginnings and fresh starts. It is a time to get out and enjoy the longer days and warmer weather.

Here are some of the signs that spring is coming:

• The days start to get longer. The amount of daylight hours increases as the spring equinox approaches. This means that you will start to see more sunlight in the morning and evening.
• The weather starts to warm up. The average temperature begins to increase in the spring, making it a more comfortable time to be outdoors.
• Flowers start to bloom. Spring is a time for new growth, and you will start to see flowers blooming all around you.
• Birds start to sing. Birdsong is a common sound in the spring, as birds return from their winter migrations.
• Animals start to come out of hibernation. Some animals, such as bears and groundhogs, hibernate during the winter. They will start to come out of hibernation in the spring, when the weather warms up.

These are just a few of the signs that spring is coming. If you are looking forward to the warmer weather and longer days, then keep an eye out for these signs. You won't have to wait long for spring to arrive!