Forget leaves on the line and the wrong kind of snow; 40 years ago getting round London was not only difficult, it was downright dangerous. Laurence Alster takes a trip to Covent Garden to witness a remarkable weather report

Thick fog is a rarity in London these days, but for years the capital was infamous for its miasmic atmosphere. Right up to the 1950s, so noxious were its “pea-soupers” - a foul mix of fog and smoke known as “smog” - that many Londoners were shrouded permanently; in December 1952, a four-day smog contributed to the deaths of 4,000 people from bronchitis and assorted respiratory illnesses.

Those days when you could barely see your hand in front of your face are recalled in Whatever the Weather, a modest but illuminating two-part exhibition at the London Transport Museum, in Covent Garden.

Along with display cases housing home-made weather-measuring instruments (free instruction leaflets are available), the Pick Gallery is filled with black and white photographs that picture a changing social climate as much as anything meteorological.

The main themes of the photographs are sunshine, snow and smog, and how people and conveyances coped with all three. So there are pictures from 1925 of children from Dalston setting off for the seaside in a charabanc, of spectators at the Derby of the same year packed into open-topped buses, and of a tram in Islington High Street in 1952, snow swirling all around, with an adjacent bus bearing an advertisement that reads, “Paris Pounds 10.0.0d return, summer fare by Air France”.

These pictures are intriguingly detailed; those of smog-filled London rely on drama for their appeal. From the 1920s, there is an open-fronted tram by a pavement flare, its driver peering hopefully into the murk while a walrus-moustached pedestrian looks on; and, from 1956, a bus conductor carrying a flaming brand walks in front of his vehicle.

But it wasn’t all gloom, as is shown by an atmospheric photograph of day trippers at Box Hill in Surrey, in the summer of 1931. Everything points to a very different life: dressed in white-capped summer uniforms, drivers sit in open-fronted buses; even in glorious sunshine, the men wear jackets and ties and many of the women sport hats.

As if to prove that you can wait ages for an event like this and then two come along at once, the museum’s Ashfield Gallery continues the transport-weather theme with a display of London Transport posters. While the Pick Gallery is filled with weather, traffic and human sounds, here a loop tape plays radio and television weather forecasts. It reminds us that, where the weather is concerned, ours is a nation that travels in a state of constant hopefulness.

And, as suggested by the poster captions (“Pigs become restless when gales are approaching”; “When cows lie down it means rain”) we think about the weather all the time, but seldom scientifically. (Do other nations live by similar maxims?) Most of the posters play on this preoccupation by emphasising the benefits, come rain or shine, of taking the tube, train, tram or bus. Which they do, but with more style than truth. Many promise not just a means of getting from A to B but, depending on the weather, a refuge, an adventure or an escape.

Never mind. Nobody really expects advertisements to tell the truth. The main joy of this collection lies in their colour and their composition, which is often delightful. Whatever the weather, this exhibition is worth the journey.

The exhibition runs until October. Special rates available for school groups. Open 10am-6pm Monday-Thursday, Saturday and Sunday; 11am-6pm Friday. Tel: 0171 379 6344