Updated: 2026-08-13
If you are planning a trip to London and want to dodge the heaviest rain, the numbers point to a three-way tie at the top. December, November and August each register an average of 1.9 mm of precipitation per day, making them the wettest months at London St James's Park across the full 1912–2025 period. That figure, derived from the Met Office's official MIDAS archive, is your best single guide to when the capital tends to see the most rain.
Average daily precipitation in December, November and August — the wettest months in LondonLondon's reputation for rain is famous, but the reality is more nuanced than the stereotype. At the heart of the city, measured continuously at St James's Park since 1912, the difference between the wettest and driest months is small in absolute terms — yet it matters for anyone scheduling outdoor plans, from walking tours to open-air events. The data covers the full period from 1912-01-01 to 2025-12-31, giving us a robust 114-year climatological record to work with.
Autumn and late summer emerge as the rainiest window. October and September both register an average of 1.8 mm per day, while June is not far behind at 1.7 mm. If you are flexible with your travel dates, February stands out as the driest month of the year in London, with a markedly lower average of just 1.3 mm per day. That makes a mid-winter visit a surprisingly solid choice for drier weather — though, as any Londoner will tell you, the daily reality can always surprise.
The table below shows the complete monthly pattern, with each month's average daily precipitation in millimetres. These values are calculated from the full Met Office MIDAS dataset, excluding any provisional or inconsistent records to ensure reliability. The pattern is remarkably flat compared to many other European cities — London's maritime climate spreads rainfall fairly evenly across the year, with no true dry season.
| Month | Average Daily Precipitation (mm/day) |
|---|---|
| January | 1.8 mm/day |
| February | 1.3 mm/day |
| March | 1.5 mm/day |
| April | 1.6 mm/day |
| May | 1.5 mm/day |
| June | 1.7 mm/day |
| July | 1.6 mm/day |
| August | 1.9 mm/day |
| September | 1.8 mm/day |
| October | 1.8 mm/day |
| November | 1.9 mm/day |
| December | 1.9 mm/day |
Based on this 114-year record, the wettest months in London are December, November and August, all tied at 1.9 mm per day. For travellers seeking the driest possible conditions, February is clearly the best bet. The seasonal difference is modest — just 0.6 mm per day separates the wettest month from the driest — so rain should not define your itinerary. But if you are planning an outdoor wedding, a film shoot, or a walking holiday, knowing that December and November tend to edge out the rest can help you decide.
It is worth noting that these are long-term averages, not forecasts. A single year can deviate dramatically from this pattern, and London's weather is famously changeable. The data also shows that summer rainfall is not negligible — August not only ties for the wettest month but does so during peak tourist season, which may surprise visitors expecting Mediterranean-style summers. Packing an umbrella is wise year-round.
If your priority is minimising rain, aim for a winter trip. February's average of 1.3 mm per day makes it the driest month by a clear margin, and March and May are also relatively dry at 1.5 mm. If you prefer milder weather but still want to avoid the worst of the rain, April and July both sit at 1.6 mm — a middle ground that balances temperature and precipitation. Conversely, if you are booking a November or December trip for the Christmas markets or autumn colours, just plan for rain as part of the experience.
The data consistently points to late autumn and early winter — particularly November and December — as the rainiest stretch, alongside August's late-summer peak. The 1.9 mm daily average in those months translates to frequent light showers rather than prolonged downpours, a characteristically British pattern shaped by the Atlantic weather systems that roll across the capital.
At the other end of the spectrum, February's 1.3 mm average makes it the outlier in an otherwise remarkably even distribution. That gap of 0.6 mm between the wettest and driest months is the single most useful piece of information for rain-conscious travellers: it tells you that the city's climate does not reward waiting for a "dry season" — the differences are real but modest.
The reliability of these figures rests on the completeness of the Met Office's observing programme at St James's Park. The station has recorded daily precipitation almost continuously for over a century, with the record spanning from 1912 through 2025. Excluding provisional or internally inconsistent data ensures the averages reflect genuine long-term climate patterns rather than measurement anomalies.
The broader picture is one of consistency. London does not have a monsoon season or a dramatic dry period; it has a steady, maritime climate where rain is always possible but rarely extreme. The 1.9 mm daily average that marks the wettest months is not a threshold of intense downpours — it is the statistical signature of a city where drizzle and light showers are woven into the fabric of daily life. For travellers, the practical advice is simple: visit when the weather suits you, bring a coat, and do not let the prospect of 1.9 mm of rain per day change your plans.
Source: Met Office — London St James's Park station, 1912–2025.
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