Equinox & Solstice Calculator

The tropical year is 365.2422 days, so each year's seasonal markers land ~5h49m later — until a leap day yanks them back ~18 hours. Net result: a sawtooth drifting slowly earlier through each century (the Gregorian 400-year cycle over-corrects slightly mid-cycle), spanning March 19–21 for the spring equinox. 2026's dates differ from 2025's by precisely this arithmetic; the polynomial in this tool encodes the whole pattern, leap-wobble included.

No — it's the maximum of solar INPUT, not of temperature: land and especially oceans store heat, so temperature keeps rising while input still exceeds output. The 'seasonal lag' runs ~3–4 weeks over continents (July heat peaks, January cold) and 6–8 weeks near oceans (San Francisco's warmest month is September). Same physics scaled down gives the daily version: peak heat at 3–4 pm, not solar noon. The solstice is the turning of the cause; the effect follows on thermal inertia's schedule.

The sun stands directly over the equator and rises/sets due east/west everywhere — that part is exact. Day and night, however, are NOT equal on the equinox: refraction and the solar disc's width gift every latitude a few extra minutes of 'day' (the true equal-day moment, the equilux, falls days away). And the perennially viral egg-balancing claim is pure theater — eggs balance identically on any date; the equinox exerts no special force on breakfast.

Kepler's second law in your calendar: Earth reaches perihelion (closest to the sun) around January 3 and moves fastest then, so the autumn-equinox-to-spring-equinox half of the orbit takes ~179 days against ~186 for the other half. Northern winters are thus measurably shorter than northern summers (by a week!) — and southern seasons the reverse. The same eccentricity drives the equation of time's January-February lopsidedness that our sunrise tool's faq describes; one ellipse, many fingerprints.