From Mashable, it looks like some work is being done on JFK this summer:
The main arrivals runway at JFK will be closed for repairs and resurfacing for about five months starting at the end of April, just as the summer travel season gets underway, and will likely remain closed through most of hurricane season. When the winds are calm and visibility is clear, the closure of one runway doesn’t cause major disruptions at JFK, which has four runways and rarely operates all four at the same time.
I have to imagine that there’s a good reason why they’re doing these repairs during the busiest time of the year for travel for one of the busiest international airports (winter weather, probably), but this sounds like a disaster. JFK rarely uses all its runways, but as the article explains, they’re closing down the one that’s used the most often.