Updated: 2026-09-26
London's pleasant, mild days are becoming more frequent. Using the complete daily record from the Met Office station at St James's Park, the average number of fine weather days per year has risen from 134.0 in the decade 1975–1984 to 150.3 in the most recent complete decade, 2015–2024. That places the long-term average for the full 1975–2024 window at 145.0 days per year. The shift is not dramatic, but it is consistent: the capital is getting more days that feel neither too hot nor too cold.
A "fine weather day" here is defined strictly by temperature: a daily maximum of 30°C or less, and a daily minimum of 10°C or more. No humidity, wind, rain or sunshine enters the calculation. By this measure, London has gained about sixteen more comfortable days per year in the latest decade compared with four decades earlier.
The Met Office archive also allows a narrower definition: a "perfect" day has a maximum between 20°C and 30°C and a minimum above 10°C. Using that stricter filter, the data show a clear structural shift between the late 20th century and the present century.
| Period | Perfect days | Total days analysed | Percentage of perfect days |
|---|---|---|---|
| 1975–1999 | 1583 | 7303 | 21.7 |
| 2000–present | 1595 | 6209 | 25.7 |
Between 1975 and 1999, 1583 days met the strict "perfect" criteria out of 7303 days with data, a rate of 21.7 percent. In the more recent period from 2000 onward, the count of perfect days is 1595 out of 6209 days, pushing the share up to 25.7 percent. In other words, the raw number of perfect days has remained almost identical, but because the recent period covers fewer total days, the proportion has risen by four percentage points.
The increase in fine weather days is most visible in spring and autumn, when the temperature window of 10°C to 30°C is most easily met. For anyone planning outdoor events, gardening, or simply commuting on foot, the data suggest that mild, usable days are now a slightly larger part of the year than they were for the generation growing up in the 1970s and 1980s.
The St James's Park station sits at 5 m above sea level and has recorded daily temperatures since the early 20th century. Its central London location makes it one of the most reliable gauges of the city's actual microclimate. The full series used here runs from 1912-01-02 to 2024-12-31, though averages and totals are calculated only for complete years. Years with incomplete daily records – 1922, 1946, 1958, 1999, 2003, 2004, 2007, 2008, 2023 and 2025 – are excluded from annual-statistics comparisons to avoid distorting the trend.
Fine weather days in London are increasing, not decreasing. The clearest evidence is the jump in the average from 134.0 days per year in the late 1970s and early 1980s to 150.3 days per year in the most recent complete decade. A stricter definition of "perfect" days shows the same direction: the share of days meeting a narrower comfort window rose from 21.7 percent to 25.7 percent between the late 20th century and the current century. The change is gradual, but it is real and measurable in the official record.
Source: Met Office MIDAS archive, London St James's Park station. Period: 1912–2024 (complete years only for annual statistics). Data under Open Government Licence (OGL v3.0), held at CEDA.
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© 2026 HistoClima · data: Met Office (OGL v3.0) · not affiliated with Met Office · citation permitted with source.