Sardinian tradition says the maestrale blows for an odd number of days: one, three or five. In practice summer episodes often last 1-2 days, while in autumn and winter it can persist for up to a week. The upside: it sweeps away humidity and haze, leaving exceptional visibility.
The maestrale comes from the north-west: the best beaches are on the opposite side of the island or protected by headlands, where the wind comes off the land and the sea stays calm.
This page checks the live wind over Sardinia and highlights when the maestrale is active. In forecasts, look at the wind direction: maestrale = wind from the north-west.