According to my resources by Jim Cornell:
Best time of the year- July to Sept.
Route from Mombasa - N. along the coast than E. to Sri Lanka.
Or -
E. to the
Seychelles than E. to
Chagos than NE to Sri Lanka.
Tropical storms - Oct. to Nov.
Charts - BA: 4071, US: 71
Best time of the year - July to Sept.
From Sri Lanka - E. to the N. of
Indonesia (Banda Aceh) then SE to
Singapore.
Tropical storms - Oct. to Nov.
Charts - BA: 4707, US: 707
Best time of the year - May to Oct.
From
Singapore - N. then NW to Bangkok.
Tropical storms from May to Dec.
Charts - BA: 4508, US: 632
I hope this helps a little........................_/)