The meteorological year starts in December which is why December appears as the 1st data point in the charts below.\u00a0 All data is supplied by the Met Office and can be found here<\/a>.<\/p>\n I decided it was time to refresh the layout of the charts. The dashboard below now shows all 8 charts I show each as a single graphic.\u00a0 The middle bottom block explains why some data points are in black, points out that the charts for Sunshine & Frost are swapped around according to the seasons and how the abnormality index is calculated.<\/p>\n In July 2025<\/a>, the Met Office extended their historical frost days data back to 1931.<\/strong><\/p>\n Chart H displays my UK Weather Abnormality Index<\/strong><\/span> (see my May 2019 post for details<\/a>).\u00a0 The closer to zero this index is, the less abnormal and thus more “average<\/em>” a month is.\u00a0 The higher it is, the more abnormal the month is.\u00a0 When the index is over 100%<\/strong>, we can describe the month as unusual in some way.<\/p>\n The abnormality index was 53% <\/strong>this month which is in line with the median of the last 94<\/strong> years.<\/p>\n ** update ** I must apologise for an error in the abnormality index calculations during the spring & summer of 2025.\u00a0 As mentioned in the dashboard above, the abnormality index is based on teh 6 variables shown in charts A to F but not chart G.\u00a0 Between March & October, chart G shows Frost days which obviously is not relevant at that time of year but in the winter it is replaced with sunshine hours which again is not relevant for that season.\u00a0 In 2025, I inadvertently kept the winter calculation going throughout the summer which means sunshine during the spring and summer played no part in the calculation.\u00a0 This error has now been corrected which is why chart H will look a little different from the last few months.<\/em><\/span><\/p>\n <\/p>\n PS: If you bookmark this link<\/a>, it will be refreshed with the latest month’s data.\u00a0 I usually post the update in the first week of each month.<\/em><\/p>\n Click the relevant month below to see what the weather was back then.\u00a0 Months highlighted in bold had an abnormality index exceeding 100%<\/strong> indicating unusual weather.\u00a0 Alternatively click the Weather Tracker<\/a> hash tag below this post to see a list of all such posts.<\/p>\n For analysis of trends by seasons, please click on the relevant season from this list or the Weather Trends<\/a> hashtag below this post.<\/p>\n For analysis of trends by year, please click on the relevant year from this list –<\/p>\n![\"\"](\"https:\/\/marriott-stats.com\/nigels-blog\/wp-content\/uploads\/2025\/11\/UKweatherTracker202510-Summary.png\"){kind=tracking}
<\/p>\nHow abnormal was October 2025?<\/strong><\/span><\/h5>\n
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