Every square kilometre of the United Kingdom, placed by how much sunshine it gets and how much rain falls on it. Where is it sunny and dry, where dull and wet, where both at once, and how has that changed since the 1960s?
British weather talk runs on two numbers: how much sun, how much rain. The Met Office measures both at hundreds of stations and spreads them, with careful statistics, onto a grid of one kilometre squares that covers the whole country. That grid, HadUK-Grid, is open data. I took its thirty-year averages for 1991 to 2020 and for 1961 to 1990 and put every one of the UK's 245,077 squares on two scales at once.
The map below colours each square by both. Sunshine runs from pale to marigold, rainfall from pale to teal, and a square that is both sunny and wet goes a deep aubergine. Every colour is a mix you can read: hover over the key to light up just those squares, change the season or month, move the breaks, or switch to the 1960s.
The pattern is the one most of us carry in our heads, drawn sharper than we usually draw it. Sunshine and rainfall pull hard against each other: across all the squares, the rank correlation between them is −0.72. The south and east are sunny and dry, the north and west dull and wet. Sunshine varies by a factor of 2.5 across the country, from 1,992 hours a year on the shingle at Dungeness in Kent to 784 in the square that holds the summit of Ben Nevis. Rainfall varies by a factor of 10.2, from under 500 mm on the Isle of Sheppey (493 mm) to 4,796 mm in the fells at the head of Borrowdale in the Lake District.
One square is drier still: a single coastal square at the mouth of the Tees, with 469 mm. Its neighbours average 599 mm, so I treat it as a quirk of the gridding at the edge of the land rather than a real dry spot.
Type a town, village or postcode, use your location, or click the map. You get the square's sunshine, rain and daytime highs for every month, how it compares with the rest of the UK, and how it has changed since 1961 to 1990. Then ask the map where else has weather like yours.
With equal-share breaks, each third of the UK's land is "sunny", "middling" or "dull", and each third is "dry", "middling" or "wet". If sun and rain were unrelated, each of the nine boxes would hold a ninth of the country. They do not. Two corners are huge and two are almost empty.
Click a card to light up its squares on the map. The sunny and wet corner is the interesting one. Sunshine in Britain comes mostly from the south, the sea and the clear air behind weather fronts; rain comes mostly from the west and the hills. The far south west is exposed to both, so Cornwall's coasts can be among the sunniest in Britain and still catch well over a metre of rain. Dull and dry is the reverse: the lowlands round the Moray Firth sit in the lee of the Highlands, so the rain has fallen before the air arrives, but they are far enough north that winter days are short and cloud is common.
People and land do not match. The sunny and dry third holds 339 of the 803 UK towns and cities with 15,000 people or more and 49% of their population. The dull and wet quarter holds 0.7%.
The sunniest squares in the UK are almost all beside the sea. Of the 1% of squares with the most sunshine (at least 1,797 hours a year), 80% lie within 5 km of the coast, though only 19% of Great Britain's land does. 82% of them are in the South East region: the Isle of Wight, the Sussex and Kent coasts and Dungeness. Cloud tends to build over warm land during the day, especially in spring and summer, while the air over the cooler sea stays clearer, so the coast keeps more of the sun.
Within each nation, the coastal strip is the sunny part. The first 2 km of England get 1,684 hours a year against 1,505 more than 20 km inland; in Wales it is 1,578 against 1,331. Across Great Britain as a whole the effect hides, because so much of the coast is in Scotland.
Switch the map to 1961 to 1990, or to "What changed". The UK of 1991 to 2020 was sunnier than the UK of 1961 to 1990 by 75 hours a year on average (5.6%), and wetter by 79 mm (7.2%). Both at once: 90% of the land got sunnier and wetter. Only 8.3% got duller and 1.5% drier.
The brightening is strongest in England (7.5%) and weakest in Northern Ireland (1.8%). Within England it is biggest in the North East (11.1%) and the East Midlands (10.1%), and the towns that gained most are on Tyneside and in south Northumberland: Ashington, Blyth and Bedlington all gained 17.5% or more. Sheffield gained 14.8%. The area with more than 1,600 hours of sun a year grew from 9,881 km² to 42,725 km².
The UK's sunny third grew from 26,992 km² to 81,886 km², using the same break.
Look closely at the "What changed" map and you will see rings and blobs: patches of strong or weak change centred on single places. These are the fingerprints of individual weather stations whose records changed more or less than their neighbours, spread out by the gridding. So read the change map for its broad pattern, not for your own square.
Why the broad pattern? I do not test causes here, and the two periods differ in how sunshine was measured as well as in the weather. But the pattern fits a well-known story: the smoke and sulphur haze of the industrial towns cleared after the Clean Air Acts of 1956 and 1968 and the decline of heavy industry, and the old industrial North East and Midlands are where the sun grew most. The wetter decades fit the long-term rise in UK rainfall the Met Office reports, which is concentrated in winter and in Scotland.
Pick any month or season in the map's "When" menu (the monthly maps load when you ask for them). Across the UK, May is the sunniest month on average and December the dullest and the wettest. May is the sunniest month in 72% of squares and July in 27%, mostly in the south and east. In December, Ventnor on the Isle of Wight gets 67 hours of sun; parts of Shetland get 9.
The wettest month varies more: December in 28% of squares, October in 26%, November in 24% and January in 15%. The wet west gets more of its rain in winter: 32% falls in December to February in the wettest third of the land, against 25% in the driest third.
A sister project asks how many months a year are pleasantly warm across the whole world, counting months whose average daily high falls in a band. Here is the UK at 1 km with the Met Office's maximum temperatures. With the default band of 18 to 27 °C, 25% of the land has no such month, and the most anywhere is 5, in and around London. Move the band and watch the country change.
Among the 803 UK towns and cities with at least 15,000 people (GeoNames), Folkestone is the sunniest, with 1,937 hours a year, ahead of Sandown on the Isle of Wight and Dover. Among all 1,426 towns in OS Open Names, Ventnor (1,955 hours) tops the list. Fort William is both the dullest and the wettest bigger town (927 hours, 2,405 mm), with the Rhondda close behind on rain. The driest are in south Essex: Southend-on-Sea gets 526 mm. Of the 30 places with 250,000 people or more in GeoNames, Southend is sunniest and Belfast dullest (1,271 hours). London gets 1,559 hours and 618 mm.
Data. The Met Office's HadUK-Grid (version 1.3.2) interpolates observations from the UK's weather stations onto a 1 km grid on the British National Grid, using regression on geography (height, distance from the coast, urban land and so on) and smoothing of the leftovers between stations. I used its thirty-year averages: annual sunshine hours and rainfall for 1961 to 1990 and 1991 to 2020, and monthly sunshine, rainfall and mean daily maximum temperature for 1991 to 2020. There are 245,077 land squares. HadUK-Grid is published by the Met Office through the Centre for Environmental Data Analysis under the Open Government Licence.
Classes. By default the breaks are the terciles (3 by 3) or quartiles (4 by 4) of the squares, each square counting as one square kilometre, so every row and column of the key covers the same land area; you can set them yourself instead. The colours are my own, mixed from four corners in a perceptual colour space. For "What changed", the classes are of percentage change.
Places. Towns are GeoNames places with 15,000 or more people (not counting parts of other places) and the cities and towns of OS Open Names; each takes the mean of the land squares within its 3 km block. Regions come from the nearest OS Open Names place; Northern Ireland is its own land area on the grid. Distances from the sea are measured from the grid's coastline.
Limits. These are averages over thirty years, not any one year, and a grid is a model of the weather between stations, not a measurement in every square: values in remote hills rest on few stations, and the hilltop figures are estimates. Sunshine recorders changed over the decades (from the glass-ball Campbell-Stokes recorder to electronic sensors), and the station network changed too, so part of the change between the two periods may come from the instruments. The page stores values in a compressed form, so the figures it shows are rounded slightly; every number quoted in the text comes from the full-resolution data.