By now, you've probably heard that the entire tri-state and much of the region is under a Frost Advisory Sunday night/early Monday. High pressure helping to funnel very cold air from Canada is the culprit.
While our big temperature swings this spring are certainly unusual, cold weather in May isn't. In fact, we've had temperatures drop to 38 degrees or lower as late as May 30th, 1947.
Even so, this cold weather is odd. Our last frost in the spring is typically in the first two weeks of April, so we're about a month over the average.
The good news is this will not be a killing freeze. We would need temperatures below 30, usually 28 or lower, for several hours to have a freeze.
This will be mainly a patchy to scattered frost event with lows in the mid to upper 30s. Sensitive plants like tomatoes, are most at risk. Cover any non-cold hardy plants with a cloth sheet or a specialized cover for frost. Never use plastic which offers no protection from the cold temps.