Johannesburg is typically 7 hours ahead of New York. When it's 9:00 AM in New York, it's 4:00 PM in Johannesburg. South Africa does not observe DST, but New York does.
During US daylight saving time (March to November), the difference is 6 hours. During US standard time (November to March), Johannesburg is 7 hours ahead.
Optimal meeting window: 8:00 AM - 10:00 AM New York time (2:00 PM - 4:00 PM Johannesburg in DST, or 3:00 PM - 5:00 PM in winter). Morning New York catches afternoon Johannesburg.
South Africa has significant mining and financial ties to the US. Major US companies have operations in Johannesburg, Africa's economic hub.