Category: Commentary

The flow of moist, warm air from the continent pushed the thermometer to a maximum of 14.2C on Monday. This was 4.1C above the 34-year November average and close to the October mean and the warmest day in November.

After a sunless day on Sunday I recorded 1.9 hours of sun on Monday.

The thick cloud persisted overnight that meant much of the warmth did not radiate into the atmosphere providing another very mild night in that the thermometer did not fall below 10.5C.

Tuesday continued with much cloud and the wind having veered a few degrees from the predominantly easterly flow yesterday to the southeast on Tuesday.

A depression to the west of the country gave us the lowest barometric pressure this month with a reading of 997.7mb at 07.15 this morning.

Update on Tuesday at 16.49: temperature eases up again with a maximum of 14.4C being 4.3C above the average. Wind increasing during afternoon with gust of 23mph at 15.13.

The mild, moist mid-atlantic air mass continued to raise temperatures above average on Sunday with a maximum of 10.8C (+0.7C) with light rain in the morning.

The rain on Sunday measured 1.6mm so we are starting another month with minimal rainfall so far. We have now experienced six consecutive months with below average rainfall. The rainfall total for the ten months of 2018 is almost 100mm below the 33-year average.

The thick cloud cover continued overnight providing a blanket that minimised warmth radiating into the atmosphere giving a minimum of 8.3C, which was 4.7C above average for November.

Monday arrived with fog blanketing the Marlborough Downs limiting visibility to 500m.

Update on Monday at 18.20: unseasonably warm, moist air lifts temperature to a 14.2C, which was 4.1C above average.

There was much more cloud on Saturday with just 2.22 hours of strong sunshine due to the effects of ex hurricane Oscar moving up the western seaboard of the UK. However, although there was little sunshine the thermometer rose well above average for November to a maximum of 12.9C (+2.8C) as the deep depression fed warm southerly air from the mid-Atlantic across the country.

The storm also meant a much windier day than of late with frequent gusts above 20mph and a peak of 26mph at 13.05.

With so much cloud and Oscar still bringing moist, southerly warm air overnight it was a very warm night with the thermometer not falling below 9.5C, which was almost 6C above the 34-year average.

Sunday arrived very gloomy with low cloud and drizzle. The thermometer at 08.00 had risen to 10.1C, which is the average Dayton temperature.

Friday gave us 7.93 hours of strong sunshine that lifted the temperature to a maximum of 10.8C being 0.7C above average for November.

During the evening the thermometer steadily fell to a minimum of 0.6C just after 8pm but then the trend was reversed and started to rise as ex-hurricane Oscar, passing to the west of the country, meant a change in wind direction from West into a more Southerly air stream.

Saturday arrived with a bright start as the cloud bank eased away to the east with weak sunshine through variable cloud.

With just 15 minutes of sunshine on Thursday and a brisk northwesterly wind, it was not surprising to find the maximum temperature was again below average, just, with a peak of 9.7C (-0.4C).

A clear sky overnight saw the thermometer fall below zero just after 20.30 and reach a minimum of -2.0C at 04.14 this morning.

Friday arrived with the sun shining strongly as it rose above the horizon triggering the recorder at 07.50. By 08.00 the thermometer had risen to -0.8C.

Review of October 2018

October brought us another month of contrasts with some daytime temperatures more likely to occur in August whilst at the end of the month we briefly endured a severe frost that was a record and more likely to be seen in the months of January or February.

The mean temperature for the month was 0.6C below the 34-year average, principally due to cool nights. The daytime mean was 0.5C above average whereas the night mean was 1.6C below average.

The second week saw two days that reached maxima in the 20’s with 22.4C and 21.3C on the 10th and 13th respectively. In contrast the during the early hours of the 31st the thermometer fell steadily to a minimum of -4.3C, this was a record for this station set up in 1984 and equals the same minimum that occurred on 30th October 1992.

A record for the coldest October day since the station began in 1984 was set on the 27th when the thermometer resolutely refused to rise above 5.2C due to strong northerly winds. The October average maximum is 14.7C.

Another example of our variable weather can be seen in that the mean for October 2018 was 9.87C, but in 1992 we experienced a very cool month with a mean of just 6.95C whereas a balmy October occurred in 2001 when the recorded mean was 12.77C.

Turning to rainfall, we have experienced the fourth consecutive below average October rainfall. The total for the month was just 44.6mm, which was 53% of the 34 year average or 40.2mm below. The wet October of 2004 produced 159.3mm whereas the very dry October in 2017 gave us only 31.3mm when the average stands at 84.8mm.

There were two very wet days on the 14th and 15th with 12.7mm and 14.8mm respectively. However, we enjoyed 22 dry days when the average is 14 dry days.

My sunshine recorder was only installed in 2014. October 2018 was a very sunny month as we enjoyed 130 hours of strong sunshine (<100watts /sq.m.) that contrasts with the average for the previous four years of 73 hours. Still on the theme of contrasting weather, the diurnal data for October shows just how much we as individuals have to adjust on a daily basis. The minimum temperature variation between day and night on the 6th was just 2C whereas a range of 17.3C occurred on the 31st as the severe frost rapidly cleared during the morning as a gentle southerly air mass arrived. This quotation from Percy Shelley sums another colourful season: “There is a harmony in autumn, and a luster in its sky, which through the summer is not heard or seen, as if it could not be, as if it had not been!” Update at 16.20 on Friday: almost 8 hours of sunshine and light winds lift temperature above average (+0.7C) to maximum of 10.8C.