Dallas is typically 14 hours behind Singapore. When it's 10:00 PM in Singapore, it's 8:00 AM the same day in Dallas. Singapore does not observe daylight saving time, but Dallas does.
During US daylight saving time (March to November), the difference is 13 hours. During US standard time (November to March), the difference increases to 14 hours.
Optimal meeting window: 6:00 AM - 8:00 AM Dallas time (7:00 PM - 9:00 PM Singapore, or 8:00 PM - 10:00 PM in winter). Early morning Dallas catches evening Singapore.
Dallas-Fort Worth is a major hub for American Airlines, which operates direct flights to Singapore. Both cities are major corporate headquarters locations in their regions.