The rainy season on the west coast of Peninsula Malaysia typically comes between April and October or November – though the levels of rainfall are only marginally higher during these months, and often the rains don't really arrive until June or July. Even during the monsoon, the rains tend to come in sharp bursts, usually during the afternoon, with sunshine for the rest of the day. Penang, however, does get heavy rains in September and October.
The east coast monsoon, which falls between mid-November and February, is more marked, churning up the seas and making some of the island destinations inaccessible. These rains also affect the interior of Peninsula Malaysia, and the whole of Malaysian Borneo.
Note: flight, boat, train and bus timetables change constantly, and airlines come and go, so please do not rely solely on this information for your travel planning. Check with relevant companies, or a flight search engine like Skyscanner, first.
Besides the major national carriers, most of which fly to Kuala Lumpur ('KL'), there are the following:
Malaysia Airlines from London Heathrow.
Air Asia from London Stanstead.
FROM NORTH AMERICA
Malaysia Airlines from New York and LA.
FROM EUROPE AND REST OF THE WORLD
Malaysia Airlines from KL to major airports worldwide (see below); also local connections from KL and from Singapore to Langkawi, Penang and Medan.
Malaysia Airlines from KL direct to: Amsterdam, Paris, Zurich, Rome, Stockholm, Jo'burg, Cape Town, Buenos Aires, Perth, Adeliade, Melbourne, Sydney, Brisbane, Auckland and all major south / east Asian airports.
Air Asia from KL to all major Malaysian and Indonesian airports, including Langkawi and Penang, plus major southeast Asian airports, including Phuket, Bangkok, Chiang Mai and Hong Kong (this is a budget carrier).
Silk Air from Singapore to other major Asian airports; also connections from Singapore to Trivandrum (Kerala) and Chiang Mai (Thailand).
Asiana from Seoul to Bangkok, with connections to KL.
Eva Air from KL to Taipei (Taiwan), with connections to North America (LA, New York, Seattle, Vancouver, San Fran), London, Amsterdam, Paris, Vienna.
Flights from UK to KL take around 12 hours.
MAS Wings is a domestic air carrier connecting various airports on peninsular Malaysia, Sabah and Sarawak.
Cars drive on the left. Roads are generally well maintained and petrol is cheap.
Malaysia is surprisingly free of health concerns, with drinkable tap water in most places and low rates of tropical disease. Officially, no inoculations are required, though it is wise to update your tetanus, hepatitis A, polio and typhoid inoculations before travelling. Malaria is a moderate problem in some remote areas, and in the interior of Malaysian Borneo. In developed parts of the country (including virtually the whole of Peninsula Malaysia) malaria has been wiped out. Doctors are likely to advise those travelling to Malaysian Borneo to take malaria tablets.
At certain times of year, jellyfish can be a problem off the beaches. Sea urchins, too, are prevalent, so watch where you stand.