1916 had the coldest June and warmest January on record, plus an exceptionally wet October day in western Scotland. The year ended with a cold December leading into a very severe winter.
January. The warmest ever (7.5C CET) on record. Not surprisingly, a month of persistent southwesterlies, often stormy with frequent gales. The record for New Year's Day (until 2022) was set this year, with 15.6 at Bude (although presumably this implies 60 ºF and a small range in possible temperatures). There were some high temperatures on the 6th: e.g. 17C at Rhyl; 16C at Tynemouth and York. On the night of the 21-22nd the minimum over the south was over 10C. High pressure over the south with depressions passing over the north meant that the south and east was very dry, while the west was very wet: 12mm in Lincs but 750mm in Kinlochquoich. 85mm in two days at the end of the month around Fort William and Fort Augustus. The only real frost all month was on the 23rd, and the lowest temperature all month was only -6 at Balmoral on the 28th.
February. Mild and stormy for the first three weeks. The winds then switched to the NE and it became much colder, with heavy snow and some severe frosts. By the end of the month there was 30 cm of snow lying in places.
March. Very snowy in the Pennines, with 3m in places. A blizzard affected the east on the 27-28th. A very cold month overall, and dull too, with under 70 hours of sunshine.
April. On the 27th 25C was recorded across much of the country.
May. Generally dull and wet, except in the E and SE.
June. Very cold and dull. Equal coldest of the century (11.8C CET). It was a dull month with many northerlies and slow-moving depressions. Rain was persistent and thunderstorms were few and far between. Aberdeen recorded 166mm in 143 hours of rain. The wettest place was the Moray Firth, with 200mm. It wasn't quite so bad in the west and south, and there was even an official "drought" (14 days without measurable (defined as more than 0.1mm now, 0.01 inches then) in the middle of the month in some places in England. The highest temperature of the month anywhere in the country was only 20C; and it only made 8C in Norwich on the 12th and Harrogate on the 13th. There were even some frosts at the start of the month, causing crop damage. Locations in the north averaged only 4 hours of sun a day for the month.
July. Cloudy, cool, and dry, although the final week was warm and sunny.
August. At first it was warm, dry, and quite sunny. It then became unsettled and cooler, with soe heavy, thundery rain. There were 89 mm of rain at Cheshunt on the 17th.
September. After unsettled start, it became dry but cloudy. A depression moving SE down the east coast then brought rain and gales to many parts from the 17th to 19th.
October. Wet and stormy. The record daily rainfall for the month of 208.3mm was set at Loch Avoich (Kinlochquoich) on the 11th. Up to this point, this was the highest daily rainfall ever for the British Isles.
November. Often wet and stormy, but mostly mild.
December. Cold (1.9C CET). Indeed, this was the coldest December of the century until 1933. Part of a very cold winter (third equal coldest winter on record).