October 2018 was a rather indifferent month with a lot of high pressure continuing the dry weather theme that began in May. This meant there was quite a bit of settled weather with pleasant spells of Autumn sunshine during the month. In fact, there was plenty but it wasn’t dry everywhere as you will see in a little moment. It was a cooler month again though compared to most months since April this year in the UK.
October 2018 was an interesting month temperature wise with a few fluctuations. The month started off fairly warm with close to average temperatures under stagnant cloud and a flat westerly flow. The second week became unseasonably warm for a time bringing the warmest October conditions for many since 2011. The third week into the fourth week was cooler as high pressure began to build leading to clear skies and patches of air frost overnight in parts. From the 26th, a northerly flow became apparent bringing down air from the Arctic resulting in the coldest October conditions since 2012 for some and others, since 2008. These fluctuations meant that October was not a particular remarkable month temperature wise overall.
The UK overall had a mean temperature of 9.6°C which comes to +0.1°C above the 1981-2010 average and made it the coolest October in the UK since 2012 though this only reflects the mild nature of the month of October recently since then.
Donna Nook, Lincolnshire recorded a maximum temperature of 26.5°C on October 13th making it the warmest October 13th on record in the UK and the latest 26°C on record in the UK (previous record was 9th October 1921 which had a maximum of 27.8°C). St Harmon, Powys in contrast recorded a minimum temperature of -8.6°C on October 30th making it the coldest October night in the UK since 1993. Quite a contrast to the night of the 12th/13th when parts of the southeast weren’t getting much below 20°C.
27th October 2018 was the coldest October day in the UK since 30th October 2008 with only two stations in the country reaching a maximum temperature of at least 10°C. The maximum temperature on the day was only 10.4°C at Langdon Bay, Kent whilst the maximum temperature at Dalwhinnie, Highlands of Scotland was only 3.0°C, very cold by October standards!
All in all, October 2018 was the fourth consecutive drier than average October though not exceptionally at 82% of average for the UK as a whole. You can see from the rainfall anomaly map below that northwestern Scotland and parts of Wales tended to be on the wetter side of average. This was down to fronts being pushed way to the north for the former and a heavy rainfall event in the second week of the month for Wales which was caused by fronts stalling against an airmass being drawn up from the south by Storm Callum thus why temperatures became very warm for that late in the season on October 13th in eastern England. From this rainfall event, Libanus, Powys recorded a daily rainfall of 159.8mm up to 0900 GMT on October 13th.
Whilst the rainfall totals may not seem that remarkably dry overall, what was remarkable was the persistence of high pressure during the month around the UK. October 2018’s 500mb height anomaly reanalysis can be seen below. Blue and purple colours mean below average heights which also mean low pressure whilst green, yellow, orange and red mean above average heights which also mean high pressure. You can see a large area of above average heights extending from the Atlantic through the UK into the east of Europe sending the jet stream way to the north. This resulted in a dry October for most and a sunny month too which we’ll get onto in a second.
If October 2018 was remarkable for at least one thing, it was sunshine. In fact, it was the fifth sunniest October on record for the UK back to 1929 and the sunniest in recent times since 2003 with 122% of the average sunshine.
With the exception of the Shetland Isles where the jet stream blew through during much of the month, the vast majority of the country had either average or above average sunshine in October 2018. In East Anglia, it was their joint sunniest October on record back to 1929 with October 1959.
In our September stats article, we mentioned how the May-September 2018 period broke records for UK sunshine. Well, May-October 2018 further continues this record breaking trend with 2018 being the sunniest May-October period on record at an amazing total of 1118.2 hours of sunshine beating the previous record of 1092.1 hours of sunshine in May-October 1959.
October 2018 brought the first October snow to the UK since 2012 on the 27th day of the month during the northerly shot of air. These were the kinds of scenes shown. Thanks to PA for sharing these amazing photos.