What decides July
The warmest month for most of the northern hemisphere, and the one where humidity rather than temperature decides how it feels.
Peak heat arrives about a month after peak daylight, for the same reason peak cold arrives a month after the shortest day: the surface takes weeks to catch up with the sun.
What July asks of you
- Feels-like now runs above the air temperature, driven by humidity rather than wind.
- Concrete and paint hit their upper limits: above 32 °C both become difficult.
- The gap between shade and sun is at its largest, which is why a patio reads nothing like a forecast.
Normals for July
Thirty-year averages from daily records, 1991 to 2020. Normal high is the average daily maximum for the month; normal low is the average daily minimum.
| Place | Normal high | Normal low | Mean |
|---|---|---|---|
| New York | 28.8 °C (83.84 °F) | 20.2 °C (68.36 °F) | 24.5 °C |
| Chicago | 27 °C (80.6 °F) | 20.6 °C (69.08 °F) | 23.8 °C |
| Denver | 30.3 °C (86.54 °F) | 15 °C (59 °F) | 22.6 °C |
| Los Angeles | 31.3 °C (88.34 °F) | 18 °C (64.4 °F) | 24.6 °C |
| Miami | 30.1 °C (86.18 °F) | 25.9 °C (78.62 °F) | 28 °C |
| Seattle | 24.6 °C (76.28 °F) | 13.7 °C (56.66 °F) | 19.2 °C |
| Minneapolis | 27.9 °C (82.22 °F) | 18.6 °C (65.48 °F) | 23.2 °C |
| Phoenix | 41.4 °C (106.52 °F) | 28.2 °C (82.76 °F) | 34.8 °C |
| London, GB | 21.8 °C (71.24 °F) | 13.4 °C (56.12 °F) | 17.6 °C |
| Paris, FR | 24.2 °C (75.56 °F) | 14.8 °C (58.64 °F) | 19.5 °C |
| Berlin, DE | 23.9 °C (75.02 °F) | 14.9 °C (58.82 °F) | 19.4 °C |
| Stockholm, SE | 21.1 °C (69.98 °F) | 14.3 °C (57.74 °F) | 17.7 °C |
| Madrid, ES | 32.3 °C (90.14 °F) | 18.6 °C (65.48 °F) | 25.5 °C |
| Rome, IT | 30.2 °C (86.36 °F) | 19.4 °C (66.92 °F) | 24.8 °C |
| Tokyo, JP | 28.2 °C (82.76 °F) | 22.3 °C (72.14 °F) | 25.2 °C |
| Sydney, AU | 15.8 °C (60.44 °F) | 8.8 °C (47.84 °F) | 12.3 °C |
| Cape Town, ZA | 16.5 °C (61.7 °F) | 9.3 °C (48.74 °F) | 12.9 °C |
| Singapore, SG | 28.4 °C (83.12 °F) | 25.2 °C (77.36 °F) | 26.8 °C |
Two things are worth reading off that table rather than just scanning it.
The gap between high and low tells you how many wardrobes the month needs. A wide spread means an afternoon and an evening that feel like different seasons, and it is always wider inland and at altitude than on a coast, because water moderates both ends.
The spread between places at similar latitudes is mostly about oceans. A coastal city and an inland one at the same latitude can differ by ten degrees in the same month, in opposite directions depending on the season.
Why the average is not the month you get
A normal is the middle of thirty years. In July, as in every month, individual years scatter widely either side of it — and memory keeps the unusual ones.
Which means the honest use of this page is as a starting expectation. It tells you roughly what to plan for and what to pack. It does not tell you what July will do this year, and no amount of historical data can, because that is a forecasting question and forecasts do not usefully reach that far.
For anything inside about ten days, use the actual forecast. Beyond it, these figures are the best available information — see best time of year to visit for how to use them when planning travel, and the average temperature tool for any city and month combination not in the table.
Your own July runs its own offset
The figures above come from one measuring point per place, usually well sited over open ground away from buildings. Your garden is not that.
Elevation, shelter, paving, tree cover and cold-air drainage all shift the local reading, often by more than the difference between neighbouring towns, and the differences are largest on exactly the clear calm nights when the exact number matters most. The mechanisms are in hyperlocal weather and temperature inversions.
The useful habit is to learn your own offset: note how your spot compares with the forecast over a few nights, and apply that difference from then on. It is the one piece of information no climatology has.