For practical purposes: (Northern Hemisphere) or September, October, November (Southern Hemisphere).
However, this victory is hollow. As climate change accelerates, the meteorological definition is becoming increasingly misaligned with lived experience. In many parts of the US and Europe, May now feels like summer (with 30°C/86°F heat waves), while March retains a stubborn winter chill. The three-month block is a relic of a more stable climate. The question “Which are the spring months?” is a Rorschach test for how you view time. If you see time as a celestial clock, you choose the equinox to solstice. If you see it as a data set, you choose March–May. If you see it as a living system, you watch for the first bud. which are spring months
For truth: Watch the maple sap run, listen for the peepers, and ignore the calendar. In many parts of the US and Europe,
would say: late March through late June. But this is awkward for calendars. The phenologist would say: it depends on your latitude and the year’s temperature anomaly. But this is too complex for daily life. The meteorologist has won the popular vote. In global weather reporting, climate data analysis, and most everyday conversation in North America and Europe, March, April, and May are now the de facto spring months. If you see time as a celestial clock,
The most honest answer is that spring is not a set of months but a process —a thermal and biological transition that, on a warming planet, is starting earlier and ending no later. The months of spring are not a destination on the calendar. They are a fleeting, shifting boundary line that we humans, desperate for order, have tried to paint in permanent ink on a world made of water and warmth.
Ask a child, “What are the spring months?” and the answer is almost automatic: March, April, May. Ask a climatologist, an astronomer, a Celtic druid, or a farmer in the Australian outback, and you will receive four different, equally valid answers. The seemingly simple question of which months constitute spring reveals a fascinating collision between celestial mechanics, human culture, meteorology, and the biological reality of a warming planet.