Highest temperature in Milan on September 10?

What this question means

Milan on 10 September, with a moderate spread: 21°C at 34%, 22°C at 26%, 20°C at 15%, 23°C at 11%, and 19°C at 4%.

Note the option at the top of the range — "24°C or higher" at 7%. Open-ended buckets like that behave differently from single values, because they collect everything above a line rather than one outcome. A 7% reading there is not a forecast of 24°C; it is the combined chance of 24°C and every warmer possibility.

That asymmetry is worth watching whenever a range question caps one end. Here the top bucket carries more weight than the single degree below it, which tells you the crowd sees more room for an unusually warm day than the tidy peak at 21°C suggests on its own.

Early autumn in northern Italy sits between settled summer and variable winter, and the distribution reflects that — neither the near-certainty of the tropical questions here nor the wide scatter of the temperate spring ones.