Highest temperature in Shanghai on September 9?

What this question means

Shanghai on 9 September — and comparing this with the 10 September question on the same city shows something worth knowing about forecast horizons.

Here the peak is 28°C at 57%, with 29°C at 37% taking most of the rest. The next day's question has the same peak value but only 44% on it, spread across a wider set of neighbours.

The nearer date is sharper. That is not a coincidence: weather forecasts degrade with distance, and a day closer to resolution means better information and a tighter distribution. Watching two questions on the same place at different removes is a clean way to see that effect isolated from everything else.

The tails here are thin — 27°C at 5%, 30°C at 4%, 31°C at 3%, 26°C at 2% — reflecting a system with little room for surprise over this timescale. A distribution concentrated on two adjacent degrees is close to the practical limit of what temperature forecasting offers.