Chicago is typically 14 hours behind Singapore. When it's 9:00 PM in Singapore, it's 7:00 AM in Chicago. Singapore does not observe daylight saving time, but Chicago 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: 7:00 AM - 9:00 AM Chicago time (8:00 PM - 10:00 PM Singapore, or 9:00 PM - 11:00 PM in winter). Early morning Chicago catches evening Singapore.
Chicago's financial services and trading firms coordinate with Singapore's banking sector during these overlap hours.