An afterglow of Summer – review of September 2021
September started settled and warm, but finished cool and wet – so just how warm or wet was it overall?
Well, the summery weather lasted for most of the month. Consequently it was our second warmest September of our 37 years of records. The 6th recorded 28.7°C making it the third warmest September day on record.
It was mostly dry, although a thundery low passing through on 14th delivered rain all day, totalling 28.7mm in all, making this the fourth month in a row with a day of more than an inch of rain, or the fifth month in a row with more than 20mm in a day. It was also the fifth month in a row with more than the average rainfall, though in September’s case only just, totalling 61.6mm against the long term average of 59.4mm. In fact rain fell on just ten days, which is below the average for September.
The mostly settled weather also resulted in relatively light winds, until the Atlantic resumed its influence and a series of blustery lows moved through on the last four days, which all had maximum wind gusts over 20mph, topping at 28mph (Force 6) on 27th.
Is this the precursor to a wet and windy October? We shall see!
|Measure||Unit||Minimum||Average||Maximum||Average min||Average max||Total|
|Wind source (most common/highest gust)||Sector||E||WSW|
|Wind high gust||mph||1.9||28||13.5|
|Rain daily accumulation||mm||2.1||28.7||61.6|
|Solar irradiance during daylight||W/m²||197||814||590|
|Sunshine (sunny if irradiance > 300 W/m2)||Hours||3.3||7.0||99|