Windrush Weather

Category: Commentary

  • Summary for May and Spring 2015

    Summary for May and Spring 2015

    MAY 2015
    In 1802, Dorothy Wordsworth wrote “A very cold morning – hail and showers all day…. William tired himself with seeking an epithet for the cuckoo”.

    Many of us will sympathize with William, as there have been several days in the last month when it has been very cool, accompanied by frequent showers. Small hail fell in the showers on the 19th and thunder was heard on the 3rd.

    There were two days when during the majority of the day the thermometer did not rise above 10C, (15th and 19th), the 18th and 19th fared little better with maxima of 12C before late afternoon. However, the coldest day occurred on the 14th when a maximum of 8.5C was the best that was recorded before mid-afternoon. Comparing these days with the long-term average for May of 16.6C indicate how cool some days were during the past month.

    The mean temperature for the month was 0.4C below the long-term average, principally due to the cold days as the mean minimum was just above the 31-year average. It was notable that there were no air frosts during the month although several ground frosts did occur. The very cool nights meant that many plants in gardens were not badly frosted but have been somewhat stunted in their early growth.

    The frequent showers produced a total of 83.1mm, which is 139 per cent of the long-term average or plus 47mm. It is interesting to note that the amount of moisture evaporating into the atmosphere from ground and water sources also from plant matter matched this total of 83mm.

    Strong sunshine totalled 116 hours, which is some 70 hours less than the splendid April just past. The UV level was the lowest for May over the past 6 years, even though the levels were in the ‘High’ category towards the end of the month.

    At times the past month has been a little depressing but not quite as bad as was written by Horace Walpole on 28th May 1774 – “We are almost freezing here in the midst of beautiful verdure with a profusion of blossoms and flowers: but I keep good fires, and seem to feel warm weather while I look through the window, for the way to insure summer in England, is to have it framed and glazed in a comfortable room”.

    SPRING 2015
    The mean temperature for the past three months was 0.2C above the long-term average, the warm April offsetting the cool May. Rainfall for the three months totalled 129mm, which is just 72 per cent compared with the 32-year average, a deficit of 50mm.

  • Minimal rainfall and considerable evaporation

    After 13 days this month the rainfall total is just 6.3mm when the average for April is 61.4mm. In contrast, the evaporation from the ground, plants and water surfaces is 28mm due to the rising temperatures and drying winds.

  • Very dry March with mean temperature just above long-term average

    The total rainfall for March was 27.9mm, which is 48.5% of the long-term average and the fifth driest I have recorded. The mean temperature was 0.2C above the 32-year average. A fuller analysis will follow shortly.

  • No UV and lowest solar energy for a month, that was the 11th

    Yesterday the 11th was the gloomiest day for over a month. With thick cloud trapped under the anticyclone no ultra violet radiation was recorded and solar energy was the lowest since 5th January.
    Not surprisingly with continuous cloud cover, the difference between maximum and minimum temperatures was just over 2C in the twenty-four hour period (5.1C to 2.6C). The humidity at 0800 was low at 84%, again the lowest for a month.