Washington DC is typically 13 hours behind Singapore. When it's 9:00 AM in Singapore, it's 8:00 PM the previous evening in Washington DC. Singapore does not observe daylight saving time, but Washington DC 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 PM - 10:00 PM DC time (7:00 AM - 10:00 AM Singapore next day, or 8:00 AM - 11:00 AM in winter). Evening DC catches morning Singapore.
Singapore and the US have strong diplomatic and trade relations. The US-Singapore Free Trade Agreement was the first such agreement between the US and an Asian country, driving significant business travel between these capitals.