On the whole September was a fairly quiet, but disappointing month, both notably wetter and colder than average, but which in the second half of the month brought some interesting weather.

  With a particularly disturbed period of weather 18-19th that had two named storms, preceded by an ex hurricane, which collectively brought a day of gales and one particularly wet day, which became the eighth wettest in my records and which was then followed by a cold spell with some ground frosts, September certainly heralded the start of autumn.

  The month might appear to have been uneventful with there just having been one 'day of ...' (a gale on the 19th), but that wasn't really the case. Storms 'Helene, Ali and Bronagh' came in quick succession and then there was the first air and ground frosts of the season, which by recent standards are quite early and additionally on the 24th Maulds Meaburn was the coldest location in NW England, so there was at least something to write about.

  MSLP of 1018.2 Mb was +4.1 Mb above the local average for September which considering the cool and wet aspect to the month with sizeable unsettled spells, is quite a surprisingly large departure.

  Overall a mean minimum of 7.71°c and a mean maximum of 15.65°c saw the temperature 1.4°c below the 1981-2010 average. It was the coldest since 2015 and of the ten now recorded, two have been colder and seven warmer. The highest maximum temperature recorded was 20.0°c (2nd), the lowest minimum -0.6°c (24th).

  Rainfall of 125.7 mm (Crosby Ravensworth School 134.8 mm  -  Castlehowe Scar 157.1 mm  -  Reagill 96.8 mm) was 150.7% of average for 2007-17 and made it the driest September since 2016. Of the twelve now recorded, nine have been drier and two have been wetter - although with four years being within 3.2 mm of each other, 2018 could have been anywhere between from the second to the fifth wettest.

  At the Met' Office site at Newton Rigg, rainfall of 94.6 mm (124%) was the driest since 2016 and in a series back to 1900 (data missing in 2 years), September has been drier in 81 years and wetter in 35 years.

  A mean temperature of 11.78°c is the warmest since 2016 and in a series back to 1951, September has been warmer on 42 occasions, colder 21 times and with 4 years having the same mean temperature.

  Locally, rainfall percentages were above average, typically around 115-125%, but with Brothers Water at 94.3% being a notable exception.

  Figures from the Environment Agency’s rainfall sites were, (figure in brackets being the monthly average for 1961-90)   ‘Data kindly provided by the Hydrometry and Telemetry team of the Environment Agency (Penrith)’:

  Kirkby Thore ** mm (69.7 mm)

  Haresceugh Castle (Kirkoswald) 102.42 mm (88.1 mm)

  Brothers Water 229.15 mm (243 mm) and

  Orton (Shallowford) ** mm (127.1 mm [average for 1967-2017])

  362.6 mm at Seathwaite Farm (Borrowdale - 270 mm [average for 1981-2010]).

  ** not yet available

  1st - 7th    It was something of a battle between areas of high pressure (HP) and low pressure (LP) at the start of the month and consequently the weather was somewhat mixed with no particular pattern becoming established.

  HP was centred in the North Sea on the 1st, moving towards Denmark, but a frontal system associated to LP near Iceland was never too far away from the UK and which did bring a little rain at times. Although the frontal system made slow progress against the HP, rainfall totals were slight on the 1st and 2nd. The days were generally overcast, in particular on the 3rd when the front did finally move across the UK, bringing a grey, drab day and 6.7 mm of rain.

  However, the 1st and 2nd had been mild, the 2nd more so at 20°c, but the cold front on the 3rd saw the temperature fall to 15.7°c.

  Then it was the turn of HP in the Atlantic to ridge in over the UK and this did result in more of the way of sunshine on the 4-5th despite more fronts encroaching on the UK from the north. Towards the end of the period the HP was barely exercising any control as it became squeezed south by the fronts from the north. However, behind a cold front that had moved south and created a nominal N'ly flow, the HP ridged back in overnight and the result was the first ground frost of the season (-1.2°c), relatively early by recent standards.

    Midnight 6th -   Marginal high pressure behind a cold front that brought the autumn's first ground frost