Washington, D.C. is 7 hours behind Nairobi
Best overlap: 3:00 PM to 6:00 PM in Nairobi is 8:00 AM to 11:00 AM in Washington, D.C..
3:00 PM to 6:00 PM in Nairobi is when Washington, D.C. is also working, at 8:00 AM to 11:00 AM their time. You get roughly 3 hours of shared time, so aim for the middle of that window to keep the call comfortable for both teams. Heads up: because Washington, D.C. changes its clocks and Nairobi doesn't, the difference moves by an hour twice a year. Confirm the overlap around the DST switch.