There's really no way to know very far in advance when the last snowflakes will fly in any given winter. In some years it might be in February, in others April.

But we can use the past to estimate the probability of seeing snowflakes on any given day over the next couple weeks, just to see what the chances are. Here's a chart that shows those probabilities based on the last 100 years of data. Of course, the general trend from here on out is downward. Around now, for example, the probability of having a day with at least a few snowflakes is about 10%, and there are a few days in early April when the chances are about the same. By mid-April, however the probability is down to around 5%, and essentially goes to zero by the end of April. However, there are a few reports from the 18th and 19th centuries of snowflakes even in early May in this area.

But if you're tired of shoveling snow, take heart in that I could only find 12 April storms in the last 100 years that dropped an inch or more of snow, which works out to about one every nine years, on average. It's interesting to note, however, that one of those accumulating April snows came just last year.