Overview
- University of British Columbia researchers report Sydney’s climate-defined summer rose from about 76 days in 1990 to 125 days in 2023.
- In Sydney, the typical summer window shifted from early January–early March in the 1960s to early November–late March in 2014–2023.
- The team compared 10 mid‑latitude cities by combining ERA5 climate reanalysis with local weather‑station records for consistent tracking.
- Summers expanded by roughly six days per decade on average across the cities studied, while Sydney lengthened by about 15 days per decade.
- The study finds summers now start and end more abruptly and accumulate more heat, raising bushfire risk, driving up cooling demand, and prompting NSW officials to push emissions cuts and local cooling plans, with news outlets noting a discrepancy over the journal that published the paper.