Brunei Darussalam, (officially the State of Brunei, Abode of Peace), is a country located on the north coast of the island of Borneo, in Southeast Asia.

Climate

Brunei Darussalam has an equatorial climate. The average annual temperature is 27.1°C (80.8°F), with the April-May average of 27.7°C (81.9°F) and the October-December average of 26.8°C (80.2°F). Brunei is warm to hot year-round, with heavy (albeit variable) rainfall that peaks from September to January

Money
The official currency is the Brunei dollar (B$), but Singapore dollars are widely used and have the same value as the Brunei dollar, meaning they are accepted at face value. Don’t worry if you receive Singapore dollars as change from a Brunei dollar bill – you’ll have no trouble using them anywhere in Brunei.

Banks give around 10% less for cash than travellers cheques.

Brunei uses 1c, 5c, 20c and 50c coins, and notes in denominations of B$1, B$5, B$10, B$50, B$100, B$500, B$1000 and B$10, 000.

ATMs are common, and if the banks are closed you can usually find a moneychanger who can also change travellers cheques. Bargaining is reserved for taxis, water taxis and markets (not for food). Credit cards are widely accepted.

Visas
Countries whose citizens are eligible for visa-free entry for 14 days include Belgium, Canada, Denmark, France, Indonesia, Italy and Japan. Nationals of Germany, Ireland, Malaysia, the Netherlands, New Zealand, Singapore, South Korea and the UK are among those eligible for 30-day visa-free entry. US citizens do not need a visa for visits of up to 90 days. Australians are issued on arrival with a visa valid for a 14-day stay or can apply on arrival for a 30-day multiple-entry visa (B$20), which is useful if you are traversing the country overland, say, from Miri up to Kota Kinabalu.

It’s a good idea to ring your nearest Bruneian embassy or consulate to confirm what visa options are available to you.

There are visa-granting facilities at the borders with Sabah and Sarawak, but the process is time-consuming – it’s much easier if you can organise one in advance of your visit.

The above information are from

http://www.lonelyplanet.com/brunei-darussalam/weat 

www.tuniu.com/places/26736