For example, in cities like Sydney (Australia), São Paulo (Brazil), and Cape Town (South Africa), summer officially begins on the December solstice. In 2024, that date is ; in 2025, it will be December 21 as well, though the exact time varies by time zone.
It's important to note that meteorologists and climatologists often use a simpler system for record-keeping: they define summer as the three hottest months of the year, which in the Southern Hemisphere are . This meteorological summer always starts on December 1 , regardless of the solstice.
Thus, while the “official” astronomical summer begins around December 21–22, many practical calendars—and even some national weather services—consider summer to have already begun on the first day of December.
