Meteorology Section Report: 2011-12

By Philip Eden

The Met Office's automatic weather station (hereafter called the AWS) has functioned continuously throughout the year with no gaps in the record at all.

The overlap continues between the old AWS and the new AWS, so our own automatic station continues to function. The ideal time scale for the overlap is 5% of the station record for long-standing sites, and never less than two years for shorter-lived sites. So that means ideally five years for us – of which we have now completed 2 years and 3 months – although if the old AWS fails before that period is concluded I shan't ask for another overhaul.

Monthly reviews of Hampstead's weather have been posted on my website, and linked to from the Society's website, usually by the 5th of the following month, though this has slipped a little during recent month due to other pre-occupations. The summaries extend back to the mid-1950s. The intention remains to extend the data online further and further back as and when time permits.

Let me now briefly summarise the weather we've experienced during the last year.

SUMMER 2011 was not a good one with temperature and sunshine duration both below the long-term average, and rainfall well above it. There were short warm spells early and late in June and in early-August, but overall this was the coolest summer since 1993. Sunshine hours were the lowest since 2008, and rainfall the highest since 2007.

AUTUMN 2011 was exceptionally warm with a record-breaking heatwave during the closing days of September and the first few days of October. It was also drier and sunnier than average. Overall, this was the warmest autumn, by just 0.2°C, in the entire 102-year long Hampstead record.

WINTER 2011-12 was mostly mild and dry, though there was one very wintry spell which lasted two weeks during the first half of February. This spell brought our lowest February temperature since 1991 and a couple of notable snowfalls, one on the 4th, and the other on the 10th.

SPRING 2012 was a season of contrasts. March was exceptionally dry and sunny with an extended heatwave during the last ten days of the month. April was Hampstead's wettest on record, as well as being rather cold and cloudy. Indeed, the mean temperature for April was lower than that for March – a rare, though not unprecedented, event. The cold and dull weather continued for three weeks in May, then we enjoyed a further 10-day spell of warmth and sunshine from the 22nd onwards.

Philip Eden 19 June 2012


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Last updated   27-Aug-2012