New York is typically 13 hours behind Singapore. When it's 3:00 PM in Singapore, it's 2:00 AM in New York. Singapore does not observe daylight saving time, while New York does.
During US daylight saving time (mid-March to early November), the difference is 12 hours. During US standard time (November to March), it's 13 hours.
Optimal meeting window: 8:00 PM - 10:00 PM New York time (9:00 AM - 11:00 AM Singapore next day). This catches morning business hours in Singapore.
For morning calls from New York, 7:00 AM - 9:00 AM works well (8:00 PM - 10:00 PM Singapore same day).