Since 1970 the average date of New York's first measurable snowfall has been December 14 (six days later than the 30-year period before that, 1940-1969). It has occurred as early as Oct. 29 (in 2011) and as late as Jan. 29 (in 1973). It has happened before Dec. 1 in seven years (including the winter of 2018-19) and occurred later than Jan. 1 fifteen times (including the winter of 2015-16). When this first snow arrives, on average, it's accumulated two inches.
In two out of five winters the first snowfall amounts to less than an inch; five had first snowfalls that measured just 0.1" (the last time was in 2010). On the flip side, there have been nine winters with first snowfalls that accumulated more than four inches (most recently, the 10.5" snowstorm of Dec. 16-17, 2020, the surprise 6.4" snowstorm on Nov. 15, 2018, and a 4.6" snowfall on Dec. 9, 2017). The greatest amount for a first snowfall was 15.2" on Dec. 11-12, 1960.
The average date of the first snowfall of 1-inch+ occurs on Dec. 24, ten days after the first measurable snow (and eight days later than the years between 1940-1969). It's happened as early as Oct. 29 (in 2012 when 2.9" fell) and as late as March 22 (in 1998 when 5.0 inches fell). Ten winters didn't see their first one-inch snowfall until after Jan. 15. The last time it occurred this late was during the winter of 2015-16, and it was a doozy, when 27.5" fell on 1/22 - New York's biggest snowfall of all time.
Finally, the first measurable snowfall of the 50 winters since 1970 was also the the first snowfall of an inch or more 27 times (most recently during the winters of 2019-20 and 2020-21). Additionally, eight of the first snowfalls changed to rain; four of them occurred in consecutive winters, 1984-1987. And seven of the first snowfalls began as rain before changing to snow (the most recent was the winter of 2019-20).