1917 had the coldest April on record. The summer was extremely wet; at the time it was speculated that may be this resulted from the gunfire in Flanders. It was also the third equal coldest winter on record (CET 1.5C). All three winter months were beneath 2.0C. All three months were quite cold, rather than any exceptional ones. Warm but thundery spring and early summer. There was an exceptional rainfall event in June.
January. The coldest January (1.6C CET) of the Great War. The River Mersey partly froze. Five inches of snow fell at Newquay on the 16th.
February. Very cold (+0.9C CET) and dry; part of a very cold winter. The coldest month of the Great War. There were some severe frosts in the first three weeks of the month. There was a maximum of only -5C at Benson and Ross-on-Wye on the 7th.
March. A very cold month, at 3.2C CET; only 1962 would be colder this century.
April. The coolest April on record (5.4). -15.0C, on the morning of the 2nd, at Newton Rigg in Cumbria is a record minimum. -14.4C was also recorded at Eskdalemuir the same night. There was also a notable snowfall. The first half of the month was particularly bad, with a particularly heavy snowfall in the west (particularly W Scotland and Ireland) on the 1st-2nd. -13.3C at Braemar on the 11th. The weather improved from the 19th, although there was more snow late in the month.
May. Fine and warm, but with many thunderstorms.
June. A severe thunderstorm on a hot day may have given 118 mm of rain in 2 hours at Kensington the 16th; 70 mm of rain was definitely recorded in two hours at Camden Square. Then 34C was widespread on the 17th. The record daily rainfall for the month of June is 242.8 mm, which was set at Sexey's School Bruton (Somerset) on the 28th; Aisholt in the Quantocks saw 213 mm, and 150 mm fell at Glastonbury. (There is some debate as to whether this firgure is too high, and some consider June 2020 to hold the record.) It was a very wet night across the south, with most places recording over 50 mm. A low moved along the English Channel with very heavy (occasionally thundery) rain to the north. In Somerset the rain began late in the afternoon of the 28th, peaked in the middle of the night, and continued until midday on the 29th. Needless to say, such an amount of rain led to flooding. Otherwise, one of the best Junes of the century: warm (15.2C CET) and sunny.
July. Wet at the end of the month over the southeast.
August. The second wettest of the century. July's wet end carried on into August. The month began with 53 hours of rainfall over Canterbury: continuous rain from 6.30pm on July 30 to 12.20pm on August 2. From July 29 to August 30 much of Kent recorded over 200 mm of rain. 265 mm at St Thomas Hill, near Canterbury. There were 144 mm of rain in one week up to the 4th at Margate. A thunderstorm on the 5th gave 62 mm of rain at Halstead (Essex), and severe flooding at Saffron Walden. Heavy rain in the north on the 8th: 88 mm at Ilkley. 967 millibars recorded on the 27th at Nottingham, a record low for August. Another 50 mm of rain on the 27th over Wales and the southwest; more rain over Wales and northeast Scotland on the 28th. Rainfall was 228% of normal over Wales, 194% over England, and 123% over Scotland. With so much rain about, it is hardly surprising that it was a very dull month.
October. Cold, stormy and wet the coldest of the century in Scotland. Snow in the north. There was snow in northern Ireland on the 26th. In spite of the overall cold (7.5C CET, nearly as cold as 1919), there was a warm start, with 24C at Southend on the 2nd.
November. One of the three occasions this century when November has been warmer than the preceding October.
December. Cold, dry and sunny.