Al-Qatif in Saudi Arabia's eastern province has a harsh climate: summer temperatures often reach the mid-40s, though the winter is pleasantly mild. But it is not the weather that is exercising locals and the government in these days of political turbulence across the Middle East.

Residents say all seems calm, and see no sign that security has been reinforced. But there is a mood of expectation about Friday's Saudi "day of rage" and whether the "Arab spring" will spread to the conservative kingdom.