Atlanta is typically 13 hours behind Singapore. When it's 9:00 PM in Singapore, it's 8:00 AM the same day in Atlanta. Singapore does not observe daylight saving time, but Atlanta does.
During US daylight saving time (March to November), the difference is 12 hours. During US standard time (November to March), the difference increases to 13 hours.
Optimal meeting window: 7:00 AM - 9:00 AM Atlanta time (7:00 PM - 9:00 PM Singapore, or 8:00 PM - 10:00 PM in winter). Early morning Atlanta catches evening Singapore.
Atlanta's Hartsfield-Jackson airport is the world's busiest, while Singapore's Changi is consistently rated the world's best. Both are major transportation hubs for their regions.