London is 2.1°C (3.8°F) warmer by day, Chicago gets 262 mm (10.3 in) more rain a year.
Chicago is at its warmest in August and coolest in January, while London peaks in July and bottoms out in February. Month for month, London is the warmer of the two in 7 of 12 months.
Chicago is the wetter of the two, collecting 967 mm (38.1 in) of rain a year against 705 mm (27.8 in) in London. The most comfortable time to visit is July, August and September in Chicago and June, July and August in London.
| Chicago | Metric | London |
|---|---|---|
| 🌡️ Temperature | ||
| 12.2°C | 🌡️Average daytime high | 14.3°C |
| 6.6°C | 🌙Average nighttime low | 6.2°C |
| August | 🔥Hottest month | July |
| January | ❄️Coldest month | February |
| 🌧️ Rain | ||
| 967 mm | 🌧️Annual rainfall | 705 mm |
| May | ☔Wettest month | October |
| January | 🏜️Driest month | April |
| 💨 Climate | ||
| 81% | 💧Average humidity | 85% |
| 4.4 m/s | 💨Average wind speed | 3.4 m/s |
Overnight, Chicago typically falls to around 6.6°C (43.9°F) while London settles near 6.2°C (43.2°F).
Chicago is hottest in August and coldest in January, whereas London peaks in July and is coolest in February.
Chicago sees the most rain in May and the least in January; London is wettest in October and driest in April.
London feels the more humid of the two, averaging 85% relative humidity against 81%.
For London, the pick of the year is June, July and August.
Month by month, here is the coldest night, the average day and the hottest afternoon each city can expect. Switch Compare to read rainfall, humidity, wind or solar instead, and Period to move between the long-term 45-year average and any single year — the shading is a quick warm-to-cool guide.
| Month | Chicago | London | ||||
|---|---|---|---|---|---|---|
| Min | Avg | Max | Min | Avg | Max | |
| January | -5.5 | -3❄️ | -0.5 | 1.3 | 4❄️ | 6.7 |
| February | -4.6 | -2 | 0.6 | 1.2 | 4.4 | 7.5 |
| March | -0.6 | 2.2 | 5 | 2.5 | 6.5 | 10.4 |
| April | 3.6 | 6.7 | 9.8 | 4 | 8.7 | 13.3 |
| May | 8.4 | 11.6 | 14.8 | 7.1 | 11.9 | 16.7 |
| June | 14.4 | 17.5 | 20.6 | 10 | 14.9 | 19.9 |
| July | 19 | 21.7 | 24.4 | 12.3 | 17.4🔥 | 22.4 |
| August | 19.2 | 21.9🔥 | 24.5 | 12.3 | 17.3 | 22.4 |
| September | 15.6 | 18.5 | 21.4 | 10.1 | 14.8 | 19.5 |
| October | 9.3 | 12.2 | 15.1 | 7.5 | 11.3 | 15.1 |
| November | 3 | 5.6 | 8.1 | 4.3 | 7.2 | 10.2 |
| December | -2.4 | -0.2 | 2.1 | 2.4 | 4.9 | 7.3 |
| Annual Avg | 6.6 | 9.4 | 12.2 | 6.3 | 10.3 | 14.3 |
Min / mean / max temperature (°C). 🔥 marks each city's hottest month, ❄️ its coldest; shading runs cool blue to warm red.
The same figures plotted out, so the shape of a typical year is easier to see than in a grid. Where the two lines run close together Chicago and London feel alike; where they separate, they are genuinely different places to be.
Hover or tap any point to read the exact figures. Chicago London
See how Chicago and London stack up against other cities. Swipe for more.
Choose which city to keep, then search for any other city in our database — we'll build the comparison for you.
Quick answers to the questions people ask most when comparing Chicago and London — each drawn straight from the climate figures above.
London is the warmer of the two. It averages daytime highs of 14.3°C (57.7°F) against 12.2°C (54°F) in Chicago — roughly 2.1°C (3.8°F) warmer by day.
Chicago is hottest in August, averaging highs of about 24.5°C (76.1°F), while London peaks in July at around 22.4°C (72.4°F). That makes Chicago the hotter of the two at the height of summer.
Chicago gets colder. In its coldest month (January) overnight lows average about -5.5°C (22.2°F), compared with 1.2°C (34.2°F) at the low point of the year in London.
Chicago is the wetter city, collecting about 967 mm (38.1 in) of rain a year versus 705 mm (27.8 in) in London. Chicago is wettest in May and driest in January; London is wettest in October and driest in April.
London is the more humid of the two, averaging 85% relative humidity over the year against 81% in Chicago.
The most comfortable months in Chicago are July, August and September, when average temperatures are at their mildest.
London is at its most pleasant around June, July and August, based on the mildest average temperatures of the year.
London is the warmer city in 7 of the 12 months of the year. The gap is widest in January, about 7°C (12.6°F), and narrowest in May, about 0.3°C (0.5°F).
Chicago has the bigger seasonal swing, about 24.9°C (44.8°F) between its coldest and hottest months versus 13.4°C (24.1°F) in London — so London has the steadier, more even climate.
It depends what matters most to you: choose London for warmer weather, pick London if you prefer drier conditions and go for Chicago if you want lower humidity. There is no single "better" climate — it comes down to whether you value warmth, dryness or comfort most.
Every figure on this page is calculated from NASA POWER satellite climate data spanning 1981–2025 (45 years). The averages describe the long-term climate of Chicago and London, not a single year's weather or a short-range forecast.
