By Philip Eden

It was the warmest October on record, thanks to southerly winds which prevailed throughout the month. But pressure was often low over the British Isles so the weather was also very changeable with frequent heavy rain.

The Central England Temperature (CET) for October 2001 was 13.5C, which was 3.1 degC above the mean for the standard reference period 1971-2000. It was easily the warmest October in the CET record which began in 1659, smashing the previous record of 13.0C set in 1969. It was even fractionally warmer than September; the only other time this happened was in 1672. The anomalous warmth was most pronounced at night - the night-time CET was 3.6 degC above normal while the day-time CET was 2.6 degC above. There were no air frosts at any of the 120 sites monitored during October - an unprecedented event, and throughout the country night minima were frequently above 10C. There were some exceptionally warm days too: the date record was equalled on the 13th when the temperature reached 24.8C at Northolt in London, and a new date record was established on the 30th with readings of 21C at L'Ancresse on Guernsey and 20.3C at Hawarden near Chester.

Rainfall for the month averaged over England and Wales was 129mm which is 60% above the average. October 2000 was much wetter, and there were in all 22 wetter Octobers during the 20th century. In the main population centres in Scotland the provisional monthly total for October 2001 was 121mm which is 59% above normal, while the Northern Ireland total of 84mm exactly equalled the long-term average. Parts of Norfolk and Lincolnshire actually had less rainfall than usual, while several places in the Home Counties and the western Midlands recorded two to three times the normal amount. There was serious flooding in Sussex and Kent around the 9th, in Herefordshire, Cheshire and northeast Wales on the 21st, in Cambridgeshire and Essex around the 23rd, and in the Scottish highlands around the 30th.

Sunshine over England and Wales totalled 90 hours, about 15% below the long-term average for October. The equivalent figures for Scotland were 72 hours (17% below), and for Northern Ireland 82 hours (8% above). Monthly aggregates ranged from a mere 40 hours at Eskdalemuir in Dumfriesshire to 142 hours at St Helier on Jersey and 139 hours at Hunstanton in Norfolk. Several places in southwest Scotland recorded their dullest October since 1982.