Bangkok is typically 12 hours ahead of New York. When it's 9:00 AM in New York, it's 9:00 PM in Bangkok. Thailand does not observe DST, but New York does.
During US daylight saving time (March to November), the difference is 11 hours. During US standard time, Bangkok is 12 hours ahead.
Optimal meeting window: 8:00 PM - 10:00 PM New York time (7:00 AM - 9:00 AM Bangkok next day in DST, or 8:00 AM - 10:00 AM in winter). Evening New York catches morning Bangkok.
Thailand is a major US ally in Southeast Asia and a top tourist destination. Many US companies have manufacturing operations in Thailand's growing industrial sector.