Guernsey Met has confirmed that the island had its warmest summer since records began in 1843.
Between June and August, there were six days when temperatures reached 30 degrees celcuis or higher, including an all-time high of 36.4°C on 25 June.
The average temperature was just under 19 degrees - almost three degrees above normal.
Senior meteorologist Robert Plummer says the records are usually broken by much smaller margins.
"You expect to go up mainly by something like 0.1 of a degree per decade or something, but in this case we've jumped up 0.9 degrees in just four years, from 2022 to 2026.
"We can't say from that that it's going to keep going at that rate, but you can see that if you did warm at that rate, we would just be heating up just insanely fast.
"There's nothing to tell us that that's exactly what's going to happen, but it's certainly quite alarming.
"When we had our hottest ever day, about 36.4 in Guernsey and 39.3 in Jersey, it didn't just shave a bit off the record, it smashed it.
"It's a little bit unsettling because we can't keep smashing records.
"We won't recognise the climate in a short amount of time if that happens; we just have to hope that it's a bit of a one-off, but time will tell."
In summer 2026, the Bailiwick also received around half its usual rainfall and had an extra 162.7 hours of sunshine.
Summer 2026 in Guernsey - Warmest summer since records began in 1843. pic.twitter.com/eS1sgs6wjx
— Guernsey Met (@GuernseyMet) September 2, 2026
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