The first honest thing to say about London weather is that it is less rainy than its reputation and far more changeable than almost anywhere. The long-term averages put the city somewhere around 600 to 720mm of rain a year, spread thinly across roughly 110 days — less than Rome, less than Milan. What that produces is not downpours but grey half-hours: a sky that spits at you on the walk to the museum and has cleared by the time you come out. Any month can hand you four seasons before lunch.
So rain is the wrong axis on which to choose your dates. The three things that genuinely change a London trip are light, crowds and price, and unlike the weather all three are predictable.
Key facts
- Our pick for balance of weather, light and crowds: typically May, June and September
- Longest days: around midsummer, when the sun sets close to 9.20 p.m.
- Cheapest and quietest window: January and February
- Shortest days: late December, dark shortly before 4 p.m., barely eight hours of daylight
What actually changes from month to month
Start with light, because it dictates how much of a day you get. At the June solstice London holds something in the region of sixteen and a half hours of daylight; at the December solstice, a little under eight. That swing of nearly nine hours is larger than anything you would feel in Paris or Rome, and it is why a December itinerary identical to a June one delivers roughly half as much. Two outdoor things before dark is a full winter day; in June you can do four and still eat outside at nine. Note the clock change too — Britain goes back on the last Sunday in October, and an afternoon that ended around half past five suddenly ends before five.
Price moves just as predictably. Live rate scans through 2026 put average London hotel nights at roughly £110 to £115 in January, near £140 in October and November, about £150 in December, and close to £175 to £185 across June, July and August. The same room can cost well over half as much again in high summer. Budget somewhere around £165 to £220 per person per day for a mid-range trip covering hotel, food and transport.
Rainfall barely moves by comparison: November is typically the wettest month at roughly 68mm and March around the driest at roughly 48mm, a difference of well under an inch across an entire month. Sunshine is the honest winter problem. July averages in the region of 219 hours of it; December something like 54.
Spring: the parks in full performance
From late March, London's parks put on the show that justifies the city. Kew Gardens in the south-west is the one we would cross town for — magnolias and cherry through April, bluebells in the woodland after — with adult admission somewhere in the low twenties of pounds, cheaper booked online in advance. Allow the best part of a day and take the District line, which leaves you a short walk from the gate. Closer in, the Isabella Plantation inside Richmond Park is at its most dramatic in late April and early May when the azaleas go off, and it costs nothing.
May is the classic month, in our view: mild days, squares in bloom, a city that has stopped feeling damp. The RHS Chelsea Flower Show usually falls in the third week of May, opening days reserved for RHS members and general admission following. Two things follow. It pushes hotel rates up noticeably across Chelsea, Belgravia and South Kensington that week. And the free alternative, Chelsea in Bloom, fills the surrounding Chelsea shopfronts at the same time with floral installations you can walk past without a ticket.
One habit worth adopting: Columbia Road Flower Market in the east runs on Sundays only, typically from around eight in the morning to the early afternoon. Arrive before the crowd thickens mid-morning, or deliberately at the very end, when sellers cut prices rather than cart stock home — then build the rest of that Sunday around Shoreditch and Bethnal Green rather than trekking back across town.
Two spring dates to check before booking. The Boat Race, usually a weekend afternoon in late March or April, runs along the Thames between Putney and Mortlake and is free from the towpath. The London Marathon, usually a Sunday in April, closes a long corridor of central and east London roads for most of the day. Neither should change your dates; both should shape the day they land on. And pack for two climates, because spring hands you both — a warm afternoon in a park still ends in a cold, drizzling evening.