Young Black Haired Girl With Blue Eyes Reveals On The Green Glade With A Spring Tree

Astronomically, the vernal equinox (currently usually 20 March in the Northern Hemisphere, and 22 or 23 September in the Southern Hemisphere), should be the middle of spring (based on the angle of the sun and insolation) and the summer solstice (usually 21 June in the Northern Hemisphere and 21 December in the Southern Hemisphere) should be the middle of summer (because the sun is at its highest), but daytime temperatures lag behind insolation by several weeks because the earth and sea have thermal latency and take time to warm up.
During the vernal equinox the sun's rays are directly above the equator, making day and night (but not daylight and darkness) nearly equal on all parts of the world.
Some cultures, such as those that devised the Celtic and East Asian calendars, call the spring equinox "mid-spring", but others (especially in the USA and sometimes in England) regard it as the "first day of spring". For most temperate regions, signs of spring appear long before the middle of March, but the folklore of 21 March being the "first day of spring" persists, and 21 June as the "first day of summer" is common in the USA. In South Africa, Australia and New Zealand, spring begins on 1 September, and has no relation to the vernal equinox. In Ireland spring traditionally started on 1 February.
In South America, the Tupi-Guarani calendar, from the former inhabitants of what is presently Brazil, Northen Argentina and Paraguay, counted 365 days, plus a fourth part of a day, needing no extra day every four years. The beginning of the solar year was marked by the rising of the M25 Constellation in the horizon, which occurs between June 5 and June 11 in this part of the world. For these native peoples, the four seasons were clearly identified by the solstices and equinoxes. The trajectory of the Sun throughout the year was divided into "The New Age" (Ara Pyau) and "The Old Age" (Ara Ymã). Ara Pyau was spring and summer, and Ara Ymã was autumn and winter. This calendar, which had no graphed or written form, marked activities such as hunting, fishing, planting, harvesting and religious rituals.