Spring bulbs, and woody plants such as lilac, bloom time schedule has to do with the increasing hours of daylight which is pretty predictable but also the temperatures and rainfall which are much less so. For now, I can give you the range of dates that we have had the lilacs in flower over the past decade or so as well as the estimated peak time. As that date gets closer, you can look at the Spring Bloom Tracker on the NYBG website for information that is updated daily.

The range of flowering dates for lilacs is April through Mid-May with an expected peak in Mid-April. The dogwoods, crabapples, daffodils and cherries are all expected to peak within that same April to Mid-May time range so if the lilacs aren’t just perfect, there is a good chance something else will be. 

Courtesy of NYBG Plant Information Service