September began with high pressure bringing sunny periods and light south-westerly winds. Showers overnight 3rd/4th brought just 2mm rain. The next few days until 11th were cloudier, but dry, with variable light wind. The barometer rose still higher, remaining high until 19th, with the corresponding sunny conditions.

Maximum temperatures during the first three weeks were fairly consistently around high teens to low twenties, with the highest 24.1°C on 12th. Night temperatures remained mostly in double figures except for the minimum for the month of 5.7°C on 8th and, with clear night skies, single figures during 17th-20th.

This all changed on 21st when the barometer fell sharply with the arrival of a depression and its associated warm air. The temperature rose to 24.9°C, the warmest day of the month. Daytime temperatures following remained around 20°C and nights between 11.0°C and 15.0°C. The pressure continued to fall until 24th. Then 6.5mm of rain fell on 22nd and 28.2mm on the night of 23rd/24th.

The rest of the month continued unsettled, with some rain on every day, but with only significant amounts of 13.1mm on 28th and 8.6mm on 30th. This brought the total for the month to 65.1mm, 126% of my 25-year average and makes it the second wettest month of the year, but only just 0.3mm less than June. The year's total so far is now 368.7mm, 78% of average.

The first three weeks of September were pleasantly settled and dry overall with a few brief periods when three narrow frontal systems passed through quickly leaving nominal amounts of rain. The last ten days were wet but warm and with some sun every day. Overall it was a warm month, 1.2°C above my 30-year average.

Mike Wilkins

25 year Rainfall averages are from 1992-2016
30 year Temperature averages are from 1981-2010