Although many winters have a significant snowfall and a cold snap in March, it often happens in the first two weeks of the month, and is usually limited to one snow event and a few days of cold weather. This post, however, looks at three years that fell within a twelve-year period in the middle of the 20th century that experienced freakish snow and cold in the second half of the month.
1956 (March 12 - April 8)
During this four-week period 25" of snow fell and temperatures were 6.5 degrees below average. There were snowfalls of 6.7" and 11.6" that occurred two days apart, on March 16-17 and March 18-19, and then a 4.2" snowfall occurred on April 8 (as well as two smaller snowfalls under two inches). Up until these four wintry weeks just eight inches of snow had fallen for the entire winter.
1958 (March 14-21)
On March 14 there was a snowfall of 4.1" followed a week later (March 20-21) by a nor'easter that dumped 11.8" of wet snow. (This storm paralyzed an area from Maryland, eastern Pennsylvania and much of New Jersey with 20-40 inches.) And while temperatures in NYC were colder than average during both snowfalls, temperatures much of the time were above freezing. This ended up being the snowiest month of the winter.
1967 (March 15-23)
During this nine-day period 15.4" of snow fell from three storms, and temperatures were 15 degrees below average. On the 18th, the high/low was only 20°/10°, which was 27 degrees below average. Then, on the morning of the 19th the low fell to 8° above zero, the latest date on record for a single-digit reading. From late afternoon on the 15th until noon on the 20th the temperature was 32° or colder. This brutal cold was followed by a 10" snowfall on March 22.