February 1998

Despite a very cold start and a cold end to the month, this is the warmest February on Fair Isle since records began in 1974. The previous highest mean daily temperature for the month was 5.7° Celsius recorded in 1992. The mean sea temperature - 1.7° Celsius above the normal 6.5° Celsius - is also the highest February figure recorded. On 23 out of 28 days winds were between south and west in direction at 09 hours.

February 1998 began very cold, with a blast of Arctic air bringing a record minimum temperature of –5.6° Celsius on the 2^nd – with up to 6 cms of lying snow. The weather soon turned mild, with above average temperatures by the 3^rd. The run of mild weather persisted right through until the last two days of the month. This outbreak of arctic air, together with above average sea temperatures, resulted in thunderstorms on the 27^th and a snow cover on the morning of the 28^th. (Another outbreak of Arctic air early in March resulted in further dramatic thunderstorms in the Northern Isles).

With more than twice the usual rainfall (218.1%), this is the wettest February recorded on Fair Isle. Sunshine totals were, not suprisingly, well below average.

Taking Scotland as a whole, this was the warmest winter month on record – the departures from average almost 6° Celsius over the Eastern Highlands, with somewhat lower values in maritime regions.

The reason for the exceptional warmth of February was the unusually large amount of time that Scotland lay under the influence of a ‘warm sector’. Between the 3^rd and 25^th of the month, only 6 days were spent outside such warm sectors. Although mild south-westerly winds across Scotland are common, warm sectors have never lasted so long before. It is interesting to note that, while both Fair Isle and Lerwick had twice the normal rainfall for the month, Fair Isle’s total of 139.5 mm - benefiting from the ‘rain-shadow’ effect of the Scottish mountains - was much lower than the 214.9 mm recorded at Lerwick.

With areas of blocking high pressure never far away from England and Wales, rainfall here was well below average – with less than 25% of the nomal February rainfall over much of south-east England. Sunshine totals were above average every where except over North Wales and North-West England.