Electricity
Officially 220V 50Hz. Most outlets are the British standard BS-1363 type. Generally speaking, U.S., Canadian and Continental European travelers should pack adapters for these outlets if they plan to use their electrical equipment in Bahrain.
Understand
Bahrain is the smallest of the independent Persian Gulf states, and has often had to walk a diplomatic tightrope in relation to its larger neighbours. The country has few oil reserves, but it has established itself as a hub for refining as well as international banking, while also achieving a socially liberal by Gulf standards at least monarchy. Its economy depends to a small extent on Saudis interested in a little entertainment, not available in the strictly Islamic Kingdom of Saudi Arabia.
Despite being much closer to Qatar, the Hawar Islands are part of Bahrain after a long, drawn out much sovereignty dispute between the two nations.
Climate
The best time to visit Bahrain is November-March, with October & April being just bearable. Be sure to take along a sweater during December-March as evenings can be cool. Bahrain's summer, May-September, is very hot and humid, though occasional cool northerly winds blow to provide some relief. More frequent are the qaws, the hot, dry summer winds that can bring sandstorms.