First Day of Spring 2025: Date, Time & Equinox Facts

Spring arrives in the Northern Hemisphere on Thursday, March 20, 2025, at 09:01 UTC—a moment astronomers have pinpointed down to the minute. The vernal equinox marks the Sun’s crossing of the Equator heading north, and for most of the United States, that crossing happens before dawn: 5:01 a.m. Eastern time, 4:01 a.m. Central, 2:01 a.m. Pacific.

Date (Northern Hemisphere): March 20, 2025 · Equinox Time (EST): 5:01 AM · Source: NASA · Meteorological Start: March 1 · Duration: 92 days, 20 hours

The table below consolidates the essential equinox parameters for quick reference.

What is the first day of spring in 2025?

Astronomical vs meteorological definitions

Two systems define the start of spring. Astronomical spring begins when the Sun crosses the Equator moving north—an event called the vernal equinox. Britannica explains that this moment occurs when the Sun sits directly above the Equator, with the Earth’s axis neither tilted toward nor away from the Sun. In 2025, that crossing happens at 09:01 UTC on March 20. Meteorological spring, by contrast, follows the calendar: it always runs March 1 through May 31, regardless of astronomy.

The distinction matters for different audiences. Weather services and climate scientists prefer the meteorological system because it creates consistent, comparable data across years. Gardeners, outdoor enthusiasts, and holiday planners often follow the astronomical system, which aligns with natural light patterns.

Exact time and timezone details

The 09:01 UTC timing translates differently across time zones. For the Eastern United States, it is 5:01 a.m. EST, according to CBS News. In the Central time zone, the equinox arrives at 4:01 a.m. CDT, reports the National Weather Service. The West Coast sees it at 2:01 a.m. PDT, per NASA Science. That means the first day of spring technically starts before dawn for most of the United States.

Planning around the equinox requires knowing which system your context uses: weather services follow the meteorological calendar (March 1), while astronomical events follow the equinox (March 20). Confusing the two creates a three-week discrepancy that compounds across multiple years.

When does 2025 spring equinox start?

Global time variations

The equinox doesn’t happen at the same local moment everywhere. Because UTC is the reference point, regions west of Greenwich see the equinox earlier in their local day, while regions east see it later. For most of Europe, the equinox falls during the morning of March 20. For Asia and Australia, it may register as early as March 20 in local time or push into March 21 depending on the timezone offset.

The National Weather Service notes that time zones genuinely affect when you experience the equinox. West of UTC, the spring start arrives earlier in the local date. East of UTC, it arrives later. This isn’t an illusion—it’s a real consequence of how Earth rotates against the fixed UTC reference.

Why not exactly 12 hours day/night

A common belief holds that day and night are exactly equal on the equinox. NASA Science clarifies why this isn’t precisely true: atmospheric refraction bends sunlight around Earth’s curve, extending daylight slightly beyond the mathematical equal point. The Sun rises before the geometric horizon is reached, and sets after it passes. At higher latitudes, where the Sun traces a shallower path across the sky, the effect is more pronounced. Day and night are close to equal—usually within minutes—but not perfectly matched on the equinox date for most locations.

What this means: the equinox represents near-balance, not perfect equality, and your latitude determines how close you get.

Is March 21 always the first day of spring?

Historical date shifts

March 21 has cultural weight as the traditional first day of spring, but it is not the rule. On the Gregorian calendar at zero longitude, the March equinox usually falls on March 20, according to Wikipedia. The equinox can occur as early as March 19 or as late as March 21, depending on the year. This variation stems from Earth’s elliptical orbit around the Sun and the fact that a full year is approximately 365.25 days—not a clean multiple of 24 hours.

Leap years and the positioning of the February 29 shift the alignment over time. The most recent March 19 equinox occurred in 1796, and the next will not arrive until 2044, according to Wikipedia. For most people alive today, March 20 is the date to remember.

Reasons for March 19-21 range

The Earth’s orbit creates this range because the planet’s speed varies as it travels around the Sun—faster near perihelion in January, slower near aphelion in July. CBS News reports that equinox timing varies yearly due to this orbit. When the accumulated fractional days push the equinox past midnight UTC on a given year, the date shifts. The Gregorian calendar’s leap-year rules manage most of this drift, but a small residual variation persists.

The pattern: equinox timing drifts about six hours later each year, resetting partially with each leap year.

When does spring start in Ireland?

Local equinox timing

Ireland follows the same astronomical system as the rest of the Northern Hemisphere. The vernal equinox on March 20, 2025 at 09:01 UTC marks the start of spring across the island. Because Ireland operates on Greenwich Mean Time (UTC+0), no offset applies—the equinox arrives at 9:01 a.m. local time on March 20. Meteorologically, spring in Ireland also begins March 1, consistent with the rest of the Northern Hemisphere.

The Celtic tradition of celebrating spring around the equinox connects to ancient festivals, though modern Ireland observes no official public holiday tied specifically to March 20. The cultural resonance remains, particularly in rural communities where seasonal transitions historically guided agricultural work.

Cultural celebrations

While Ireland does not have a national “first day of spring” holiday, the vernal equinox aligns with growing interest in Celtic seasonal festivals. Spring markets, community gatherings, and outdoor events increasingly mark the period around March 20. For Irish residents planning outdoor activities, the equinox marks a practical signal: daylight hours are lengthening, temperatures are climbing, and the natural world is responding.

The catch: Irish residents experience the equinox at 9:01 a.m.—mid-morning rather than pre-dawn—giving them a more visible astronomical moment than most Americans get.

How does spring affect moods?

Seasonal mood shifts

The transition from winter to spring brings measurable changes in mood for many people. Increased daylight exposure affects circadian rhythms and serotonin production. The brain responds to longer days by adjusting hormone levels, which can ease symptoms of seasonal affective disorder (SAD). This winter-to-spring mood shift is well-documented in clinical literature, though individual responses vary widely.

The first days of spring—roughly the week surrounding the equinox—often bring a subjective sense of relief even among people who don’t consider themselves affected by seasonal mood changes. Research suggests this response is partly biological: increased sunlight boosts vitamin D production and regulates melatonin, improving sleep quality and daytime alertness.

Sunlight and vitamin D impact

Vitamin D synthesis in skin requires ultraviolet B exposure, which increases as days lengthen in spring. Northern Hemisphere residents who spent winter months with minimal sun exposure often show depleted vitamin D levels by March. The spring equinox marks the point where daylight hours become sufficient for meaningful vitamin D production during typical outdoor activities. Britannica notes that the Sun’s position at the equinox places it higher in the sky than at winter solstice, increasing UVB intensity at mid-latitudes.

The implication: spring equinox timing aligns with biologically significant shifts in light exposure that affect mood and sleep quality.

The table below shows recent equinox times, illustrating how UTC timing shifts annually.

Four consecutive years of March 20 equinoxes, yet the UTC time shifts roughly six hours later each cycle, revealing the predictable drift created by Earth’s orbit.

“In 2025, the equinoxes will occur on March 20, at exactly 09:01 UTC (or 2:01 AM PDT).”

— NASA Science, skywatching guide

“The vernal equinox is one of two moments in the year when the Sun is exactly above the Equator.”

— Britannica, encyclopedic entry on the vernal equinox

For planning purposes in 2025, the choice is straightforward: astronomical spring begins March 20 at 09:01 UTC, while meteorological spring began March 1 and runs through May 31. Anyone scheduling outdoor events or seasonal activities should know which system their context uses. Weather services follow the meteorological calendar; astronomical events follow the equinox. Confusing the two creates a three-week discrepancy that compounds across multiple years.