First widespread air frost

Although there have been several grass frosts during November, last night produced the first widespread air frost of the Autumn. Air temperatures were typically minus 1 Celsius in central Shoreham and minus 2 Celsius in the more rural parts. There will be a milder interlude at the beginning of next week, but further frosty nights are likely to occur before the end of the month.

First frost

The first frost of the autumn occurred last night. For many it was just a grass frost, with the air temperature staying above freezing whilst the grass temperature dipped a couple of degrees below zero. However, at Shoreham Airport the minimum was minus 1 Celsius, suggestive of a plant damaging air frost for a few outlying gardens.

Weather in Shoreham – October 2017

A dry and mild month

Temperatures

The average maximum temperature during October 2017 in Shoreham was 16.3 Celsius (61F), and that was over 1 Celsius (1.8F) above normal for the time of year. The average minimum temperature was 10.9 Celsius (52F), and that was  also more than 1 Celsius (1.8F) above  the normal October value.

The highest temperature recorded during the month was 19.8 Celsius (68F) on the 16th. This was the day of the orange sun and day darkness caused by Saharan dust and smoke from Iberian forest fires spreading north in the southerly airstream.  The 16th was the only day with a maximum temperature above 19 Celsius (66F), however, there were 6 other days when maxima  exceeded  18 Celsius (64F). On most days (20) the temperature rose to between 15 and 18 Celsius (59-64F), but there were a few cooler days later in the month. The 22nd was the first of these less mild days with a high of 13.8 Celsius (57F). This was the second coolest day of the month. There were  3 other days when the temperature failed to reach 15 Celsius (59F), but only 1 of those days had a maximum below 14 Celsius (57F), that was the 30th, with a high of 11.4 Celsius (52F), the coolest day of the month.

There were many mild nights during October, and on 10 nights the temperature remained above 13 Celsius (55F). On 7 of these milder nights the minima were 14 Celsius (57F) or higher. The mildest nights were both the 14th  and 19th when lows of 14.8 Celsius (59F) were recorded.  There were 12 nights when the temperature fell below 10 Celsius (50F), but only 3 of these cooler nights had minima under 7 Celsius (45F). The end of the month was coolest with 3 out of the last 4 nights recording temperatures below 5 Celsius (41F). The coolest night was the 30th with a reading of 3.2 Celsius (38F).

The sea temperature,  around 17 Celsius (63F) at the beginning of October,  fell slowly to 14 or 15 Celsius (57-59F) by the end of the month.

Frost

There were no frosts in Shoreham during October. The lowest grass minimum was 0.0 Celsius (32F) on the 28th.

Rain

There were 30.4 millimetres (1.2 ins.) of rain during October, and that was less than 50% of the  average. Rain fell on 15 days, about 2 days above what one would expect at this time of year, and wet days ( rainfall of 1 millimetre (0.04 ins) or more)  amounted to 9 days. The first half of the month was generally dry, and although measurable rain fell on 6 days, the total was only 6.8 millimetres  (0.3 ins.) between the 1st and 16th. Rain then fell on the following 9 days with 9.2 millimetres  (0.36 ins.) recorded on  the 19th and 5.6 millimetres  (0.22 ins.) collected on the 20th. Most of the rain was then light, and during the last 6 days of October there was no measurable rain.

*A rain day is from 0900-0900 UTC

Hail

There was no hail reported  in Shoreham during October.

Thunder

There was no thunder reported in Shoreham during October.

Wind

October was another ‘westerly’ month with well over half of winds blowing from between southwest and northwest.  It  was often quite breezy early in the month, and again  during the unsettled spell,  but it became generally less windy towards the end of October. At Shoreham Airport,   a gust of 42 knots (48 mph) was recorded in the early hours of the 20th,  with 45 knots (51 mph) measured during the afternoon on the following day.

Fog

There was no fog observed in this part of Shoreham during October except for a while in the evening and overnight on the 25th/26th.

Statistics for October 2017

Reporting Station Highest Temp Lowest Temp Rain Total (mm) Wettest Rain days
Shoreham Airport 20.0 0.9 39 9 19
Thorney Island 18.8 3.1 38 9 18
Gatwick Airport 21.4 0.8 34 8 17
Herstmonceux 21.5 4.1 39 10 17
Bournemouth (Hurn) 19.3 -1.4 46 11 17
Middle Wallop 19.1 1.2 36 8 13
Dieppe 24.4 6.3 48 22 15
 

Storm Brian, the wind and waves

Storm Brian, so named by the Irish Met. Service, was felt along the Sussex coast during Saturday. Squally winds, gusting to over 50 mph at Shoreham Airport, accompanied sudden downpours. Although the storm was not exceptional for the time of year, it was accompanied by some fairly high tides and very high seas. A local buoy reported waves regularly in excess of 5 metres,  some of which were captured on camera by the Old Fort.  Not a day to cross the Channel by ship, in fact some of the windiest weather  has been in the Channel Islands, with Alderney reporting gusts of 63 mph.

  

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Orange sun and day darkness

The eerie orange sun followed by day darkness was not a precursor to the end of the world, but an unusual, if entirely natural, sequence of events. Easterly winds over north Africa produced some very warm weather in the Canary Islands but the air was thick with Saharan sand. Meanwhile, hurricane Ophelia was edging northeastwards to the west of Iberia where prolonged drought has caused numerous forest fires. As Ophelia became a deep, but extra-tropical,  depression, it rushed north towards southwest Ireland dragging the Saharan sand and smoke from Iberian forest fires  with it. It caused the sun to weaken and appear orange. Thick, mostly upper level, cloud associated with the remnants of the hurricane,  together with the sand and smoke, led to near darkness in the middle of the afternoon. Fortunately, very little rain fell, but the few spots that dropped from the leaden skies were very dusty, and those with light vehicles could hardly fail to notice a colour change.