Chennai is 9.5 hours ahead of Washington, D.C.
Best overlap: 8:00 AM to 9:00 AM in Washington, D.C. is 5:30 PM to 6:30 PM in Chennai.
The hours that work for both Washington, D.C. and Chennai are 8:00 AM to 9:00 AM (Washington, D.C.) and 5:30 PM to 6:30 PM (Chennai). You've got roughly 1 hour — enough for a focused daily check-in if you hold it at 8:00 AM in Washington, D.C. (5:30 PM in Chennai). One seasonal catch: Washington, D.C. springs forward and falls back, but Chennai doesn't, so the gap changes by an hour for several months of the year.