Guernsey was 2.6 degrees hotter than normal last month, according to the Met.
Temperatures peaked on 9 September, when it reached 29.5°Celsius.
That was the second hottest September day ever recorded on the island, which undoubtedly contributed to the monthly average temperature reaching 18.3°Celsius.
Guernsey Met says the 30-year average for first month of meteorological autumn is 15.7°C.
Total rainfall was average, but half the month's rain fell on a single day - on 16 September - when 27.2mm was recorded.
The sea temperature, recorded at St Helier harbour in Jersey, was more than a degree warmer in September compared to the 30 year average and is currently 18.4°C.
September 2023 in Guernsey was officially the warmest September on record, based on data from Guernsey Airport. This beats the previous record by 0.7 °C. See below 👇 for a summary of the monthly climate statistics. pic.twitter.com/5fpOJsIUel
— Guernsey Met (@GuernseyMet) October 2, 2023
Direct flights to Sardinia next summer
GST take cut by £3m as Guernsey's tax reform debate looms
Location chosen for more homeless sleeping pods in Guernsey
Enhancements planned for Guernsey's second harbour
European praying mantis spotted in Guernsey garden
Guernsey's leisure centre reopens after near week-long closure
Beau Sejour remaining shut over weekend
Flyers advertising polar opposites delivered in Guernsey
