Throughout September, the weather in the British Isles was dominated by high pressure and a jet stream situated to the north of the islands. The jet stream’s position blocked the colder air from the Arctic from sinking over the country keeping the temperature several degrees above normal.
September’s average temperature was 0.7°C above normal, and this continued over the first three days of October, which also had temperatures above normal. Despite the cold air block, temperatures in September were not spectacularly high, with a maximum of 21.8°C recorded on the 18th. This is considerably lower than the September record of 27.8°C set in 2011.
On the morning of Saturday 4th October, a deep area of low pressure positioned over Iceland finally managed to break the weather block, allowing cold fronts to sweep south across the country.
At 07:52, the temperature had climbed to 15.2°C, but then the cold front passed over resulting in the temperature gradually falling, reaching 10.1°C at 12:38. This brings to an end a run of mild weather and means that the delayed Autumn can now become established over the British Isles.