1786/87 (winter)

 Notably mild in Scotland. (Severe/cold winters were common at this time - so quite unusual). December was wet & stormy according to an Aberdeen paper, without much frost/snow. The remarkably mild weather affected much of January - temperatures by day in Kelso for example rising to 5 to 10 degC from late December until mid-January. February also noted as being without 'harsh' weather.

 1788

 A dry year (London/South). The driest year in the EWP series with 612mm of rain; this represents roughly two-thirds of the all-series mean. [Other dry years: 1921 & 1887 q.v.]. Includes the driest December in the EWP series, with a value of just 9 mm averaged over England & Wales. From records in the London area (quoted in 'London Weather'), both South Lambeth and Somerset House failed to record any rain during December.

 June 1788

 28th: probably the wettest day ever recorded in Suffolk.

 1788/89 (winter)

 30th November 1788 - earliest known case of a long unbroken frost began on this date, lasting until early January 1789. Although the winter overall didn't stand out as regards severity, December, and to a lesser extent January, were bitterly cold. The CET value for December 1788 was -0.3degC, some 4.4C below the 'all-series' mean for that month, and for January 1789, the value of 1.5degC was nearly 2C below the 'all-series' mean. December 1788 in particular is comfortably in the 'top-5' of coldest Decembers in the CET series. The Thames was completely frozen during this severe winter (implying a persistence of sub-zero temperatures) and a frost fair was held on the river, with the usual reports of sports / pastimes etc. "Deep snow" is noted in contemporary reports, diaries etc. (In the London area, the 'hard frost' is noted as having lasted from the 25th November, 1788 to the 14th January, 1789.(LW)
The combination of the extreme drought of 1788 (q.v.) & the bitter, frosty conditions, meant that water was in very short supply in the winter of 1788/89; much 'profiteering' as small quantities of water were sold for high prices.

 1789

 A wet summer (in London). Probably the 10th wettest year (equal with 1782) in the EWP series: in particular, May to July of that year was a particularly wet period, with a total rainfall for those three months of around 350mm (EWP), representing roughly 180% of the mean. This was of course in marked contrast to the previous (notably dry) year - see 1788.
(This was only beaten for these three months by 2007 / 415 mm May, June & July q.v.)

 1789/90 (winter)

 Very mild winter in Scotland. December 1789 began with mild, dry weather from the south-west followed by a mixture of frost and 'fresh' days, with some snow about. Frost at the beginning of January was certainly hard enough to stop ploughing, but fine, fresh weather returned from the south on 6th January and continued for the next three weeks. February continued in similar vein, with winds generally from the southwest. 
(However, winter 'arrived' in April, with severe frosts and frequent snowfall; (see below.)
[ Also a mild winter England & Wales, with an anomaly for the three 'winter' months of +2C.]

 1790 (January)

 Fog on 22 days in January (London/South).

 1790 (April)

 After a notably mild winter (see above), 'winter' weather set in with a vengeance in Scotland. Intense cold with frequent hail / snow, with snowfall in the hills more like January than April. Great deal of snow on the 12th with intense cold. Similar on the 15th, with further snowfall in Scotland. The CET value was 6.1degC, around 1.8C below the all-series mean; this month was colder than February or March this year.

 1790 (June)

 Temperature of 91degF (33 degC) on 22nd June (London??)

 1790 (December)

  December 23rd: a severe storm of rain, hail & thunder with very vivid and long flashes of lightning. It extended (reportedly) over the greater part of England & Ireland. Much damage was done to shipping and to houses in London, Windsor, Colchester etc.

 1791 (February)

 February 2nd, a notably high tide accompanied by high winds led to flooding down many east English coastal areas. Specifically, we have notes of flooding in Westminster ('Lawyers were ferry'd into Westminster Hall'), Ipswich, and other coastal areas of Lincolnshire, East Anglia & Kent. (LW/Earl Soham).

 1791 (June)

 On the 12th June 1791 (also the 2nd June 1975), snow fell in London (and elsewhere across southern England), but melted off almost immediately. [With these older reports, we always have to consider the possibility of mis-reporting soft hail etc. June 1791 is not noted as being a particularly cold month - indeed, by the CET series, it was slightly above average as far as the all-month temperature goes. However, in that other famous example, 2nd June, 1975, the cold start, with snow, turned rapidly to a fine, warm type thereafter q.v.]

 1792 (summer)

 A wet summer (in London).

 1792 (December)

According to Lamb, the month of December, 1792 is remarkable for the frequency with which gales and storm-force winds were reported from many parts of Europe, including the areas adjacent to the North Sea. The upper-air pattern must have been greatly developmental with a very strong jet persisting. 
Amongst the notable storms that Lamb (& others) analysed for this month are included: 5th (Southern North Sea), 7th/8th (whole North Sea), 10th-12th (whole North Sea) and 19th-23rd (eventually the whole of the North Sea).

 1792 (Annual)

 This was a wet year (~120% of long-term average), with a particularly wet spell from July to September, the latter month being 9th in the 'wettest' list (for Septembers) in the EWP.

 1793

 A dry summer (London/South).

 January 1794

A 'remarkable' snowstorm swept the southwest of Scotland beginning on the 23rd January 1794. It came to be known locally as the 'Gonial Blast' because of the extraordinary number of sheep that were killed, in addition to the deaths of many of the shepherds attending. [gonial/goniel=mutton of sheep]{'Weather': Vol49/p415,416}
The following is a report written after the event: " there is a place called the Beds of Esk, where the tide throws out and leaves whatever is carried into it by the rivers. When the flood after the storm subsided, there was found on that place and shores adjacent, one thousand eight hundred and forty sheep, nine black cattle, three horses, two men, one woman, forty-five dogs and one hundred and eighty hares, beside a number of meaner animals."

 1794 (summer)

 A dry, warm summer (London/South).

 1794 (Autumn)

 A very wet season over England & Wales (by the EWP series): The anomaly over the three months September, October & November was ~140%. In Norwich specifically, 'excessive rains in September, October & November occasioned a flood of the lower parts of the city; boats were rowed in several streets, and the water was from 2 to 3 feet deep in many houses.

 1794/95 (winter & early spring)

 The winter of 1794/95 was exceptionally severe, with the very cold conditions setting in on Christmas Eve 1794 (though it had been cold since November). The frost then lasted, with some breaks, until late March. The cold was most intense during January, with resulted in the coldest January (and the coldest 'any-month') in the instrumental era (as assessed by CET measure/series begins 1659). The February value of 0.8degC was 3.0C below the long-term mean. On the 23rd, the Severn was frozen and so was the Thames, with the usual 'frost fairs' being set up there. On the 25th January, an extreme temperature of (minus) 21 degC (converted from degF) was recorded at an unspecified location in England, though some references give this as 'London'(**).
A rapid but temporary thaw, accompanied by heavy rain began on the 7th February(##). This resulted in much flooding across large areas of (at least) England - extensive damage to bridges. The severe cold returned after February 12th, and (as noted above), continued well into March. Snow was noted on several occasions between 13th February & 2nd March at Syon House, then a highly rural location on the north (Middlesex) shore of the Thames, opposite Kew Gardens. The snow events were accompanied by 'easterly' winds & anticyclonic type positioned to the north.
In Scotland, it was the seventh coldest winter at Edinburgh in the series 1764/65 - 1962/63. {coldest 1779/80} Frequent heavy snowfall reported from many places in Scotland during January 1795, with transport severely disrupted.
**[There are considerable doubts surrounding the exact value here; one interpretation of the original value is that it represented -38degF, representing -39degC. This would be extreme indeed, and given that temperatures were often read inside unheated rooms at this time, and that the likely location was London (albeit a fraction of it's current size), -39degC is in my view far too low.]
##The problem was one of melting snow plus heavy rain, on top of frozen ground (which takes some time to thaw out after an extended very cold winter), coupled to a wet previous autumn: the autumn of 1794 averaged over England & Wales had around 140-150% of 'normal' rainfall, with much of the excess 'locked up' in the ground by early severe frosts from November onwards. There are many contemporary reports of buildings of 'every description' being swept away; bridges, canals, turnpikes etc., being rendered unusable. Many lives lost. Even some of the 'great' country houses of the land were 'mid-leg deep in Water', with tales of people passing from room to room in boats.

 February 1795

 Thames flood in mid-February (in London).

 April & May 1795

 April brought significant flooding after the snow of the winter (see above), and May brought more snow. On the 15th May (calendar uncertain), snow lay about a foot (30cm) deep in Aberdeenshire, and thick layers of ice covered the rivers.

 1795 (September)

 A remarkable September! It was both one of the wrmest Septembers on record, with a CET value of 16.0 degC (nearly 3C above the all-series mean), and in the 'top-5' of warmest such-named months. It was also very dry with an EWP value of just 13 mm, placing it also in the 'top-5' of dry such-named months. Indeed, at Somerset House (London), only 0.08 ins of rain was recorded, or roughly 2 mm.

 1795

 A dry year; Hot & dry in September (London/South).

 1795/96 (winter)

 One of the warmest winters (by CET) in the series which began in 1659. Up to 1997, rank=7 Value=6.20; Dec=6.6, Jan=7.3, Feb=4.7 (Others: 1686, 1734, 1834, 1869, 1935, 1975, 1989 and 1990.)

 1796

 A dry year; a dry summer (London/South).

 December 1796

 Very severe frost in London on the 25th: -21degC in Marylebone, -19degC in Mayfair. Thames frozen.
Although the winter overall did not stand out as regards low temperatures, December in particular, using the CET record, was amongst the five coldest such-named months in that record (since 1659), and included a bitterly cold spell around Christmas. The temperature in London on Christmas Eve was noted as ~(minus)21degC, and Christmas Day was intensely cold, with the Thames frozen.

 1796/97 (winter)

 A notably stormy season.

 1797

 Fog daily 16th - 28th February (London/South).
A wet summer (in London). A rather wet summer generally across England & Wales. According to Lamb (in CHMW), the anomaly was 140% of LTA (1916-1950).

 1798 (late spring)

 Persistently warm weather through April, May and June by CET series.

 1798/99 (Winter)

 Severe frost late December to early January (London/South).
Frequent, heavy snowfalls affecting at least eastern and central Scotland, from last third of December onwards. Much transport dislocation in late 1798, and again from late January 1799 onwards. (No details for elsewhere in the UK.)
A notably severe winter over western Europe / implied much of Britain (Easton, in CHMW/Lamb).
Early February, 1799 (probably 1st to 3rd), an Edinburgh paper noted that 'these 3 days past, intense frost, accompanied by heavy snow, with a strong gale from the NE. All communication with the country (Scotland) will be interrupted.' Similar story from Aberdeen for these days, there reporting snow 'for eight days past' i.e. from late January. A 'strong gale' from the NE caused much drifting. Later, on the 7th, a great fall of snow interrupted communications, and a 'great storm of snow' in the Edinburgh area on the night of the 8th is reported: newspapers on the 9th confirmed the extreme effects from as far north as Banff. Road completely blocked by blowing snow.

 1799 (spring)

 March to May: persistently cold weather by CET series. In particular, the CET value for March (3.4degC) and April (5.4degC) were some 2 to 2.5 degC below average. From records in Devon (Moretonhampstead), winds were often from between north and east. Snow also often noted. From records in Kendal (Westmorland / Cumbria), we have . . "No vegetation in the fields, nor blossoms upon the fruit trees, on the 7th May, 1799. The skins of upwards of 10,000 lambs, which perished in the spring, were sold in this town. The weather was cold and wet all through the year."

 June 1799

 22nd June: beginning of long rainy spell: only 8 days without rain in a spell lasting until 17th November.
June 23rd: snowstorm, three feet (about 1m) depth in some places in upland areas of NE Scotland.

 August 1799

 August 17th: severe southwesterly storm (with heavy rain) affected the West Country. A lot of damage reported from agricultural property (loss of crops etc.), with the Corn crop particularly affected. Fruit also severely 'blown'.

 1799 (Annual)

 Looking at the CET record, the year 1799 was within the 'top-20' of coldest years in that series [value=7.9/about -1.3C all-series anomaly](starts 1659), and for the 18th century specifically, it was beaten for low temperatures only by 1784 (7.8degC) & 1740 (6.8degC).

1800

 A dry summer (London/South).