Monthly Summary - May 2012

   May was a month of contrasts and the most un-average of average months, which, despite a succession of cool days for the first two thirds of the month somehow contrived to end with a virtually average mean temperature of 10.11°c. This followed a quite sudden and spectacular burst of hot summer weather towards the end of the month and proved that a month can not be judged until the very end.

   Until the 22nd of the month, May was, on average, colder than March and the old folklore of 'Cast ne'er a clout till May is out' never seemed more apt as we endured a long spell of cool and changeable conditions and which despite rain only falling on 14 days in the month was also very wet.

   Making comparisons with the Met' office site at Newton Rigg (Penrith) from 1961, using the averages for the standard period 1971-2000 (mean temperature of 10.2°c and 54.9 mm of rain), 27 Mays have been warmer, 20 colder, with 3 having the same mean temperature. Notably since the turn of the 1990's May has only been colder on 4 occasions, the last being in 2010. In the same period only 9 Mays have had more rain.

   The start of the month was relatively settled, although fairly uninspiring and still on the cool side - the first week of May at 6.7°c was actually colder than the last week of December (7.1°c)! The 1st-2nd saw us sat in between High pressure (HP) to our north and Low pressure (LP) to our south and this continued April's theme of cool, cloudy days with an easterly wind. The 2nd did see a little hazy sunshine in the afternoon and the temperature rose to 15.6°c (60.1°F) and this was to be the warmest day for some time.

   A special mention should be made regarding the 1st and the quite amazing cloud formations that day which had a surreal and almost other world appearance. A cover of Alto Stratus allowed for a weak sun to offer some brightness, but under this cloud cover other clouds formations cast shadows which created an eerie gloom. Cross Fell was under the influence of a Helm wind and the associated Helm bar but this also had a cap cloud over the top and just north of Penrith the relatively rare and little understood Mamma clouds were observed on the underside of a layer of stratocumulus.

   With the 3rd seeing a weak ridge of HP extending to us from its centre in the Atlantic we saw some more hazy sunshine but a weak cold front moved south on the 4th and brought a return to cloudy conditions with a spell of light rain. The Bank Holiday weekend (5-7th) was another cool affair with a mix of cloudy but bright conditions on the 5th and at least the main period of rain (7th) came later in the day.

Behind the cold front of the 4th a cold NE'ly airflow of Arctic origins persisted and then once again we entered a slack area between weather systems before the 6-7th saw us briefly under the influence of HP. This saw a run of air frosts for the 5-7th with -2.4°c (27.7°F) and ground frost of -6.5°F on the morning of the 5th the month's coldest night.

   The 6th had seen some showers in the afternoon as various troughs were circulating around the HP and after the frosty start to the 7th that HP was quickly replaced by a deepening area of LP west of Eire. This brought rain for the afternoon of the 7th then throughout the night and during the morning of the 8th. This saw 11.7 mm of rain credited to the 7th and ended what had actually been a fairly dry start to the month, but the next few days were to be especially wet!

   The 9th was a quiet day and even saw sunny intervals in the afternoon, but the rain arrived in the early evening. An elongated area of LP (996) remained over the UK through to the 11th and this LP had a series of fronts, some with waves, circulating around it. The rain, from commencing on the 9th, fell virtually without a break (there was a lull of a few hours during the early hours of the 11th) through to lunch on the 11th. The rain was at its heaviest in the early hours of the 10th and for a period in the early afternoon of that day. This resulted in 28.8 mm credited to the 9th (month's wettest day) and a further 26.1 mm for the 10th - that is over an inch of rain (25.4 mm) falling on successive days and accounted for 60% of the month's rain . At just 8.7°c     (47.7°F) and under a brisk W-NW'ly flow the 11th was the month's coldest day and marked a quite depressing couple of days.

   During the 11th HP began to nudge itself our way from the Atlantic and this briefly settled things and even brought a slight air frost on the morning of the 12th which then saw a fairly sunny day; but yet again LP was quick to return.

   The 13th (Sunday), saw that ridge of HP collapsing south as a deepening area of LP (994) situated near Iceland took charge until the 15th. The 13th was cloudy and with a cool wind that became increasingly stronger, gusting to 49 Mph, but once again the rain (5.2 mm) arrived in the early evening. This LP was responsible for drawing down air of Arctic origins and hence it was all very cool with daytime temperatures typically 10-11°c and there was even a cover at snow in the morning at Nenthead on the 15th!

   Once again a transient area of HP visited on the 16th and the day started with an air frost of -1.2°c and perfectly clear skies. However cloud was quick to build with that HP continuing to slip towards Germany as the next area of LP began to nudge in from west of Eire and which brought periods of light rain for the 17-18th. The days were still desperately cool with those NW'ly winds still been drawn down which became rather cold easterlies from the 18th and whilst the rain wasn't too prolonged, it was dull and cold.

   The 19th-20th were the last of the cold days and we sat within a col for the 20th -22nd which gave quiet days with hazy sun, but a strong ridge from a Scandinavian anticyclone dominated from the 22nd-27th with rapidly rising temperatures and humidity.

   The 22nd had seen 24.0°c and was the first of 7 successive days to attain 70°F (21.1°c) and with 26.9°c (80.4°F) on the 23rd (month's warmest day) and 26.6°c on the 24th, the leap within a matter of days from cold to hot had totally bypassed anything that resembled Spring conditions. Many sites in Cumbria were recording their highest temperatures for May.

   The screen minimum temperature on the morning of the 25th was a new 'high' of 13.1°c (55.6°F), which, quite incredibly was warmer than no less than 16 day-time maximum temperatures during the month.

   The humidity resulted in a hazy sunshine upto the 26th with a notable wind developing during the afternoons later in this period, but possibly the better days came on the 27th-28th. Both were still warm at just over 23°c but now the days were clear with perfect blue skies.

   The 28th at 24.4°c was the last day to hit the 70°F mark, and saw a return of that hazy sun, as on the 29th that HP began to decline. The 29-30th still saw sunny periods and 19°c but a series of LP systems were merging in the Atlantic and moving east and saw the month end with a wet day as a cold front moved south out of Scotland.


   Rainfall totalled 90.8 mm for the month, with rain recorded on 14 days of which 10 were 'Wet days' (1.0mm +).

   The Mean Temperature for the month was 10.11°c+         --      The Mean Max' was   15.43°c   --    The Mean Min'   4.8°c.

   We had 5 Air Frosts in the month (year 39)      --      Grass frosts totalled 9 (year 84).

   The 30 cm soil temp ranged from a low of 9.1°c on the 7th      to      a high of 17.2°c on the 29th      --      with a monthly mean of 11.8°c

   The 1 meter soil temp ranged from a low of 8.4°c on the 1st and 5-6th      to      a high of 11.9°c on the 31st      --      with a monthly mean of 9.6°c



   * May 2012 rainfall was 162.3% of the May average for 2008 - 2011

   * May 2012 was 0.4°c colder than May 2011      --      0.75°c warmer than May 2010      --      0.23 °c colder than 2009

  * The 3 month mean for March/April/May 2012 is                   TEMP'    8.02°c         --          RAIN    213.9 mm

* March/April/May 2011 was TEMP'    8.75°c -- RAIN    216.2 mm

* March/April/May 2010 was TEMP'    7.33°c -- RAIN    112.4 mm

* March/April/May 2009 was TEMP'    8.21°c -- RAIN    155.2 mm

* March/April/May 2008 was TEMP'    -- RAIN    221.6 mm


* 2012 To date TEMP'    6.29°c -- RAIN    342.4 mm

* 2011 Jan - May TEMP'    6.77°c -- RAIN    533.5 mm

* 2010 Jan - May TEMP'    4.78°c -- RAIN    173.4 mm

* 2009 Jan - May TEMP'    6.45°c -- RAIN    410.7 mm

* 2008 Jan - May TEMP'    -- RAIN    536.5 mm

 + Met office figures for May -- NW England/N. Wales had a mean temp' of 10.5°c, this being +0.4°c warmer than the reference period 1971-2000 (-0.6°c warmer than reference period 1961-90)


JANUARY 2010    FEBRUARY 2010    MARCH 2010    APRIL 2010    MAY 2010    JUNE 2010    JULY 2010    AUGUST 2010    SEPTEMBER 2010    OCTOBER 2010    NOVEMBER 2010    DECEMBER 2010   

JANUARY 2011    FEBRUARY 2011    MARCH 2011    APRIL 2011    MAY 2011    JUNE 2011    JULY 2011    AUGUST 2011    SEPTEMBER 2011    OCTOBER 2011    NOVEMBER 2011    DECEMBER 2011   

JANUARY 2012   FEBRUARY 2012   MARCH 2012   APRIL 2012  

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