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Chicago vs London weather: climate comparison
London is the warmer of the two, averaging 52°F (11°C) over the year against 50°F (10°C) in Chicago. Chicago is wetter, with 38.7 in (982 mm) of precipitation a year to London's 26.4 in (671 mm). Below: every month side by side, from 30 years of ERA5 data (1996–2025).
- Mean temperature
- 10.1°C Chicago
10.9°C London - Annual precipitation
- 982.3 mm Chicago
671.0 mm London - Rainy days a year
- 121 Chicago
128 London - Sunshine per day
- 8.8 h Chicago
7.5 h London
Month by month
| Month | Chicago | London |
|---|---|---|
| January | -0.9°C | 7.3°C |
| February | 0.6°C | 8.3°C |
| March | 5.4°C | 10.6°C |
| April | 11.4°C | 13.7°C |
| May | 17.9°C | 16.9°C |
| June | 24.2°C | 20.1°C |
| July | 26.6°C | 21.9°C |
| August | 25.8°C | 21.6°C |
| September | 22.5°C | 19.1°C |
| October | 15.6°C | 15.1°C |
| November | 8.3°C | 10.6°C |
| December | 2.2°C | 8.0°C |
Year at a glance
| Measure | Chicago | London |
|---|---|---|
| Mean annual temperature | 10.1°C | 10.9°C |
| Warmest month (avg high) | Jul · 27°C | Jul · 22°C |
| Coldest month (avg low) | Jan · -7°C | Jan · 2°C |
| Annual range (warmest high − coldest low) | 34°C | 20°C |
| Annual precipitation | 982.3 mm | 671.0 mm |
| Rainy days per year | 121 | 128 |
| Wettest / driest month | May / Feb | Nov / Mar |
| Average sunshine per day | 8.8 h | 7.5 h |
In short: London is the warmest overall (10.9°C mean); Chicago gets the most precipitation (982.3 mm a year); Chicago is the sunniest (8.8 h a day on average); London has the smallest swing between its warmest and coldest months.
Record high 1996–2025: Chicago 37.4°C (2022-06-21), London 37.9°C (2022-07-19). Record low: Chicago -32.5°C (2019-01-31), London -10.3°C (2021-02-11).
Source: Open-Meteo Historical Weather API (CC BY 4.0). Values are ERA5 reanalysis model data on a ~9–25 km grid, not readings from a weather station, so a single town’s thermometer can differ by a few degrees and local showers can be missed. Monthly means of daily ERA5 values, 1996–2025, for the grid cells nearest Chicago (41.86, -87.65) and London (51.49, -0.16).
Which months differ most?
The gap in average highs is widest in January, when London runs 15°F / 8°C warmer, and narrowest in October (1°F / 1°C apart). The biggest rainfall difference is in May: Chicago gets 2.2 in (56 mm) more on average.
Add a third or fourth city, or swap in any other place, in the full comparison tool. For one city in depth, see the Chicago climate and London climate pages.
Compare Chicago or London with another city
Questions people ask
Is Chicago warmer than London?
London is warmer on average: its mean annual temperature is 52°F (11°C) against 50°F (10°C) in Chicago (ERA5, 1996–2025).
Which gets more rain, Chicago or London?
Chicago, with about 38.7 in (982 mm) of precipitation a year and 121 days with at least 1 mm, compared with 26.4 in (671 mm) and 128 days in London.
Which is sunnier, Chicago or London?
Chicago averages more sunshine: 8.8 h a day against 7.5 h. Sunshine duration is modelled from cloud cover.
How reliable is this comparison?
Both cities use the same 30-year reanalysis, so differences are consistent. Absolute values describe a grid cell several kilometres wide and can differ by a degree or two from the airport station.