Auckland is typically 17-18 hours ahead of New York, depending on the time of year. Both cities observe daylight saving time, but in opposite seasons (New Zealand's summer is New York's winter).
When both are on standard time, Auckland is 17 hours ahead. When New Zealand is on DST and US is on standard time, it can be up to 18 hours. When US is on DST and NZ is on standard time, it can be 16 hours.
Optimal meeting window: 4:00 PM - 6:00 PM New York time (9:00 AM - 11:00 AM Auckland next day). Late afternoon New York catches morning Auckland.
Auckland is one of the furthest major cities from New York by time zone. Air New Zealand operates flights via Los Angeles, with the journey taking over 20 hours total.