So remember, contrary to what they tell you there, Nice is not in Provence and hardly ever gets the Mistral. Forecasting Accurate forecasting is very hard indeed, do not expect anything more than a short notice if any. It often builds up in the night, after midnight, or early in the morning, especially in the summer. It very rarely appears on a summer afternoon. Once established, the Mistral generally peaks in the afternoon and weakens in the evening.
Most Mistrals last one to three days, sometimes extending to a full week.
Tales abound about it always lasting a multiple of 3 days, but this notion, often quoted by landlubbers as some form of venerable ancient mariner's knowledge, is in fact utter nonsense. The sky in the NW can show telltale signs several hours before a Mistral. These appear the evening before, with a red sunset, the clouds are golden at first, turning to pink and then gray. The faster they turn gray, the harder the wind will be, force 8 or 9 is not uncommon. After sunset, short gusts of wind appear, at first in long intervals, then coming more often, while the sea current starts to flow towards the east.