Spring — March to May
Spring in London is genuinely unpredictable — you can get a warm, blue-sky day in March and a cold, driving rain shower in May, sometimes within the same week. Temperatures rise gradually from a cool 6–11°C in March to a much more pleasant 12–18°C by May, but the weather changes fast and often without much warning: London's maritime climate means fronts roll in off the Atlantic and conditions can shift within hours.
The upside is the city itself. The parks come alive — Hyde Park, Regent's Park, and Kew Gardens fill with blossom and daffodils — and the long daylight hours return quickly after the short winter days. Crowds are noticeably lighter than summer, and hotel prices are more reasonable.
Key events: the Chelsea Flower Show (May) is one of the world's most prestigious gardening events, hosted by the Royal Horticultural Society. The London Marathon runs in April, closing much of the city centre for a day. Easter weekend brings extended opening hours and events across most major museums and parks.
What to pack: layers are non-negotiable — a warm jacket for cool mornings, something lighter for midday, and always a compact umbrella or waterproof coat. Waterproof, comfortable shoes matter more than style here.
Summer — June to August
Summer is London's most popular season, and for good reason: June, July, and August bring the warmest temperatures of the year (18–24°C on average, with occasional spikes above 30°C during heatwaves) and the longest days — it barely gets dark before 9:30pm in late June. That said, "warm" in London is relative, and a rainy, 16°C August day is entirely normal. Pack for both.
The city moves outdoors as much as it can. Parks fill with picnickers, pub gardens and beer terraces overflow onto pavements, and the South Bank becomes a near-continuous street festival. Air conditioning is not standard in most homes, older Tube lines, or many budget hotels, so heatwaves can be genuinely uncomfortable.
Crowds and prices both peak in July and August. Major attractions — the Tower of London, Westminster Abbey, the London Eye — need advance booking to avoid long queues.
Key events: Wimbledon (late June–early July) is one of the world's great sporting occasions, and even without tickets, the atmosphere around SW19 and the Wimbledon Queue is worth experiencing. Notting Hill Carnival, Europe's largest street carnival, takes over west London on the August bank holiday weekend with Caribbean sound systems, costumes, and food. Pride in London (late June/early July) fills the West End with one of Europe's biggest pride parades. British Summer Time keeps evenings long enough for outdoor concerts in Hyde Park and open-air theatre in Regent's Park.
What to pack: light layers, a hat and sunscreen for sunny stretches, but also a compact umbrella or light rain jacket — a genuinely dry week in a London summer is the exception, not the rule.
Autumn — September to November
September and early October are, for many regular visitors, the best weeks to be in London: temperatures hold at a comfortable 13–19°C, the summer crowds thin noticeably, and the parks turn gold — Hyde Park, Hampstead Heath, and Kew Gardens are particularly good for autumn colour. Rain becomes more frequent as the month goes on, but it's rarely severe.
By November, the shift is unmistakable: temperatures drop to 6–11°C, days shorten fast, and grey, overcast skies become the default rather than the exception. Persistent drizzle is more common than heavy downpours — London rarely gets dramatic storms, but it can stay damp and dull for stretches of days at a time.
Key events: Bonfire Night (5 November) is marked with fireworks displays across the city, most famously at Alexandra Palace and Battersea Park. The Lord Mayor's Show, one of the oldest civic processions in the world, takes place in the City of London each November. Late November brings the switching-on of Oxford Street and Regent Street Christmas lights, and the first Christmas markets begin to appear, including the one in Hyde Park's Winter Wonderland.
What to pack: a proper waterproof coat (an umbrella alone struggles in wind off the Thames), layers underneath, and waterproof shoes. A warm scarf and light gloves become useful by mid-November.
Winter — December to February
London winters are mild by continental European standards but persistently grey and damp: average temperatures sit between 2–8°C, snow is infrequent and rarely settles for more than a day or two, and the main challenge is the lack of sunlight rather than the cold itself — some weeks see only a few hours of pale daylight between long stretches of cloud.
This is low season for tourism, which brings real advantages: shorter queues at the Tower of London and British Museum, lower hotel prices outside the Christmas period, and a more local rhythm to the city. It's also prime theatre season — West End shows and cosy, wood-panelled pubs with open fires are at their best when the weather outside is miserable.
The Christmas season (late November to early January) transforms central London. Oxford Street, Regent Street, and Covent Garden are strung with lights, Winter Wonderland in Hyde Park runs a full funfair, ice rink, and Christmas market through the season, and department stores like Harrods and Liberty put on elaborate window displays. New Year's Eve fireworks over the London Eye and the Thames are one of the biggest fireworks displays in Europe, though tickets are required to watch from the riverbank enclosures.
January and February are the quietest, coldest, and greyest months — good for a budget city break and excellent theatre availability, but pack for short days and very little sun.
What to pack: a warm, genuinely waterproof coat, layers, gloves, and a hat. Waterproof boots matter more than a heavy coat — London's cold is damp rather than dry, and it gets into your feet before anywhere else.