L’estate si sta allungando e sta accadendo più velocemente di quanto pensassimo

Summer weather is arriving earlier, lasting longer and packing more heat than it used to—and it’s happening faster than scientists had previously measured.

A new study by UBC researchers has found that between 1990 and 2023, the average summer between the tropics and the polar circles grew about six days longer per decade. That’s up from roughly four days per decade found in past research investigating up until the early 2010s.

For many cities, the numbers are even more striking. In Sydney, Australia, summer temperatures now last about 130 days, up from 80 days in 1990, adding 15 days per decade. Toronto summers are expanding by eight days per decade.

The researchers didn’t use the calendar definition of summer (June through August in the Northern Hemisphere and December through February in the Southern Hemisphere). Instead, they defined summer based on the weather: the stretch of days each year when temperatures rise above what was historically typical for a given location during the warmest part of the year—a threshold set using climate data from 1961 to 1990.

The study’s findings have implications for agriculture, water supply, public health and energy systems, many of which have been built around assumptions about when the warm season begins and ends.

“These findings challenge what we believe to be the normal cycle of the seasons,” said lead author Ted Scott, a PhD student in UBC’s department of geography. “When summer happens and how quickly it arrives impact patterns and behaviours in plant and animal life, and human society.”

Then why is it so cold where I live? It used to be much warmer this time of the year.

[Official Hungarian data of how the weather has been changing over the years, and how absurdly more heatwave periods we have now](https://cdn.discordapp.com/attachments/1030024597795504128/1492851803707146381/daysofcoldheat_hungary_budapest.png?ex=69dcd615&is=69db8495&hm=cac3ef2fc98e506ffe5deeffad53a7ed57e6b3edaa68cdafb91fb09fce789aa5)

Days of heat and days w heatwaves, are the rightmost two columns