What is the estimated frost date for fall of 2016 in New York City?
The last frost date in the spring and the first frost date in the fall are estimates that rely on historical data for a particular zone or microclimate. The spring of 2016 is a useful example of why these dates can not be relied upon exclusively to judge safe days for planting or dormancy. A good eye to the weather forecast is essential for a gardener.
With that caveat, there are some useful resources available to estimate the first frost date for an area. Cornell University Department of Horticulture publishes a map of Average Last Spring Frost Dates and Average First Fall Frost Dates for New York State. Absent a significant microclimate effect, the first fall frost for Manhattan is on average after November 10th and for most of the Bronx, between October 30 and November 10th. Other weather related statistics and information for New York State are available from Cornell on their Weather Gardening Resources page.
Courtesy of the NYBG Plant Information Service