First Day of Spring Calculator — Vernal Equinox Date Finder

First Day of Spring 2025: When Does Spring Start?

The first day of spring, also known as the vernal equinox or spring equinox, marks the astronomical beginning of the spring season. In 2025, the spring equinox in the Northern Hemisphere falls on March 20, while the Southern Hemisphere experiences its spring equinox in September. Use our calculator above to find the exact date and time for any year between 2000 and 2040.

What Is the Vernal Equinox?

The vernal equinox is an astronomical event that occurs when the Sun crosses the celestial equator moving from south to north (in the Northern Hemisphere) or from north to south (in the Southern Hemisphere). On the equinox, day and night are nearly equal in length — the word "equinox" comes from Latin aequus (equal) and nox (night). This event signals the transition from winter to spring and brings longer days, warmer temperatures, and new growth.

Astronomical vs Meteorological Spring

There are two ways to define the start of spring. Astronomical spring is based on the Earth's position relative to the Sun and begins on the date of the vernal equinox, which varies between March 19–21 in the Northern Hemisphere and September 21–24 in the Southern Hemisphere. Meteorological spring follows a fixed calendar and always starts on March 1 in the Northern Hemisphere and September 1 in the Southern Hemisphere, making it easier for weather record-keeping and climate comparisons.

When Is the Spring Equinox?

In the Northern Hemisphere, the spring equinox occurs around March 20 or 21 each year. In the Southern Hemisphere, the spring equinox occurs around September 22 or 23. The exact timing depends on the Earth's orbital position and can shift slightly due to leap years and other gravitational factors. Use our interactive tool above to see the precise UTC date and time for any year from 2000 to 2040.

Why Does the Date of the Equinox Change?

The date of the equinox varies because the Earth's orbit around the Sun takes approximately 365.25 days, while our calendar year is 365 days (with leap years adding an extra day every four years). This mismatch causes the equinox to shift by about 6 hours each year, with leap years resetting the cycle. Additionally, gravitational perturbations from other planets slightly affect Earth's orbit, introducing minor variations in equinox timing.

Traditions and Celebrations Around the Spring Equinox

Many cultures celebrate the spring equinox with festivals and traditions. Nowruz, the Persian New Year, is celebrated at the exact moment of the vernal equinox by over 300 million people worldwide. Holi, the Hindu festival of colors, marks the arrival of spring with bonfires and colorful powders. In Japan, the spring equinox (Shunbun no Hi) is a national holiday for honoring ancestors and celebrating nature. Modern celebrations include spring cleaning, planting gardens, and enjoying the first blooms of the season.

Related Seasonal Tools

Interested in the other seasonal transitions? Check out our First Day of Summer, First Day of Autumn, and First Day of Winter calculators to find the exact dates of every equinox and solstice throughout the year.

Frequently Asked Questions

What is the exact date of the spring equinox in 2025?

In the Northern Hemisphere, the spring equinox in 2025 occurs on March 20. In the Southern Hemisphere, the spring equinox occurs in September 2025. Use the calculator above to see the exact UTC time for your selected year and hemisphere.

Is the first day of spring always March 20?

No, the spring equinox can occur on March 19, 20, or 21 in the Northern Hemisphere, depending on the year. The date varies due to the difference between the calendar year (365 days) and the astronomical year (approximately 365.25 days), as well as leap year cycles.

What is the difference between equinox and solstice?

An equinox occurs when the Sun crosses the celestial equator, making day and night nearly equal in length. A solstice occurs when the Sun reaches its highest or lowest point in the sky, resulting in the longest or shortest day of the year. The spring equinox is one of two equinoxes each year, the other being the autumn equinox.

Why is day and night not exactly equal on the equinox?

While the word "equinox" means "equal night," day and night are not perfectly equal on the equinox. This is due to atmospheric refraction, which causes the Sun to appear above the horizon when it is actually still below it. Additionally, sunrise is defined as when the upper edge of the Sun appears, not its center, adding a few extra minutes of daylight.

When does meteorological spring start?

Meteorological spring starts on March 1 in the Northern Hemisphere and September 1 in the Southern Hemisphere. This fixed-date system is used by meteorologists and climatologists to simplify seasonal record-keeping, as it aligns with the calendar months and allows for consistent comparisons of weather data across years.

How is the spring equinox calculated?

The spring equinox is calculated using astronomical algorithms based on the Earth's orbital mechanics. Our tool uses the Jean Meeus approximation, which accounts for the Earth's elliptical orbit, gravitational perturbations from other planets, and leap year corrections to determine the exact UTC moment when the Sun crosses the celestial equator.

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First Day of Spring