At an average of 23°C, or 2.3 degrees above normal, last month was the six warmest October since 1922.
The mean temperature was below the norm only in some of the last days of the month, the Met Office said.
The warmest day was October 1 when the mercury rose to 30.4°C. The lowest it fell was 15.5°C on October 26.
Records show that the highest temperature ever reached in October was 34.5°C on October 27, 1999 and the lowest was 8°C on October 30, October 1978.
There were six days with thunderstorms last month, equal to the climate average.