London in May: 19°C afternoons, 9°C mornings — a 10°C daily swing — with 8 rain days of persistent light drizzle.
May in London is pleasant but unreliable. Met Office climate data (Greenwich Park) put the afternoon high at 18.6°C and morning at 9.1°C — an almost 10-degree daily swing — with around 8 rain days and 199 hours of sunshine. The range matters: a morning can start at 9°C and an afternoon can touch 22°C on warm days, or stay at 14°C under cloud. London rain is rarely a downpour; it's a persistent light drizzle that arrives unannounced and returns two hours later. Locals dress for this with layers they can rearrange fast: a jacket over a knit over a tee, where at least two of the three come off by lunch. The London rule: never look like you prepared for weather, just look like you happen to own a good trench and boots that handle damp. Classic British style leans structured cotton, wool, and leather — a well-cut trench reads more local than any technical jacket.
The London rule: never look like you prepared for weather, just look like you happen to own a good trench and boots that handle damp.

London's defining garment. A good trench reads both practical and polished — this is the city that invented it. Burberry, Aquascutum, Mackintosh, or a reasonable cotton version. Belt on rainy days, tie back on dry.

The 9°C morning layer. Thin enough to wear under a trench, warm enough for an evening walk along the South Bank.

Under the knit or alone on warmer afternoons. Stripes read deliberate in London in a way they don't in warmer cities.

Dark bottoms hide the splash marks you'll collect crossing Waterloo Bridge. Tailored trousers dress up easily for a West End show or a Marylebone dinner.

For the day that calls for something other than trousers. Tights handle the cool morning; the skirt reads appropriate for a 20°C afternoon if the sun arrives.

The London shoe from October through May. Handles puddles, cobblestones, and Tube escalators. Vans, Chelsea boots, or low leather ankle boots all work. No suede — May rain will kill them in a day.

Large enough for an umbrella, a scarf, and a paperback from Daunt Books. Leather handles rain better than canvas and ages into the city.
Breton tee · merino knit · dark jeans · trench · ankle boots · shoulder bag. Morning walk through Borough Market.
Long-sleeve tee · midi skirt · tights · ankle boots · silk scarf. Dinner in Soho, a show in the West End.
Per Met Office climate data (Greenwich Park): average daily high is 18.6°C (65°F), low is 9.1°C (48°F). About 8 days with rain totalling 44mm, plus 199 hours of sunshine. Daily temperature swings of 10°C are typical — pack for layering, not for one temperature.
About 8 rain days, mostly light drizzle rather than heavy showers. It rarely ruins a day, but it interrupts one. A compact umbrella and a water-resistant trench cover almost every scenario. Sunshine hours (199) are higher than you'd expect — more than Paris in some years.
Ankle boots with rubber soles as the primary pair (leather upper, resolable, reads local). A clean pair of sneakers or flats as the second. Skip anything with a leather sole (ruined by damp pavement) or suede upper (stained by one drizzle). Vans, Converse, Chelsea boots, and Dr Martens all read right in London May.
Most days will feel too cool. On rare warm afternoons above 20°C, tailored shorts work in parks and casual neighborhoods (Shoreditch, Peckham), but most Londoners are still in trousers or midi skirts. Locals do not switch to summer clothing until June-July at earliest.
Structured cotton and wool, leather boots or loafers, a trench, a scarf, quiet accessories. Think tailored not technical, classic not trendy. A Burberry-style trench, a merino sweater, good jeans, ankle boots: that's 80% of May London style regardless of budget or brand.