Windrush Weather

Sunshine by day, clear skies by night, then fog. Also October summary

Slowly the cloud thinned on wednesday and the sun came through with 3.80 hours of strong sunshine that boosted the temperature to a maximum of 14.4C, which was 4C above the early November average.

The clear skies overnight meant that the thermometer dropped rapidly to a minimum of 0.7C, being 3C below the November average, at 02.40 this morning. Thereafter the temperature rose slowly to 2.2C at 08.00.

Fog formed in the early hours and at dawn visibility was down to 100m.

Summary for October 2017

Another rainfall record has been broken, exactly twelve months after the last occurrence. This time the record is again for lack of rain.

With just 31.3mm of precipitation, October has been the driest month since my records began in 1984, a period of 34 years. The previous low record was set in 2016 with 31.5mm when the average was 86.4. This means a short fall of 55.1mm as compared to the long-term average or just 36%.

The heaviest twenty-four rainfall total was 10.2mm on the 19th, this midway between the wettest period of the 17th to 24th, being 73% of the monthly rainfall. We enjoyed 14 totally dry days.

The wettest October occurred in 2004 with 159.3mm, which was almost twice the average.

It has been the ninth driest January to October period I have recorded with a total of 572mm. The extremes for these ten months are 409.0mm in 1996 and 920.6mm in 2014.

It is interesting to note that the equivalent moisture lost to the atmosphere from ground sources and plant life during the month was 27.9mm. Therefore most of the rain that fell in October has been offset by evaporation.

Due to the Jet Stream providing a conveyor belt of frequent depressions the wind has been predominantly between south and west, bringing mild air, sometimes from as far south as the Azores.

This mild, moist air has meant a relatively warm month with the mean temperature 1.4C above the 33-year average. There were 21 days with above average maxima. The peak temperature of 18.9C was recorded on the 16th, some 4.3C above the average.

The stormy period around the 21st meant very strong winds gusting to 40mph. However, at the end of the month the opposite was true as a couple of very still days occurred with hardly a breath of wind such as a maximum of just 7mph on the 30th.

We suffered one air frost, that on the night of the 30th, when the thermometer fell to -0.5C, cold enough to bring to an end the wonderful colour of bedding plants that we have enjoyed for so many months.

During the month we have enjoyed 82.3 hours of strong sunshine, the sunniest being 5th with 7.9 hours followed by the 7.36 hours on the 25th. There were several dismal days of thick cloud, which were often low enough to drape the tops of the Downs in mist giving us eight sunless days.

Fog was recorded on three days.