New Brunswick, NJ

September 2020 was a month of widely-varying temperatures, several episodes of heavy precipitation, and an extended dry spell. Put it all together and conditions averaged quite close to normal. The statewide monthly average temperature of 66.8° was 1.0° above the 1981–2010 mean. While it was the seventh month of 2020 to average above normal, it was the first of these not to rank in the top 10 for warmth. Rather, it ranked 33rd warmest of the past 126 Septembers. Divisional departures from normal ranged from +0.7° in the north to +1.5° along the coast. The statewide average maximum temperature was 76.6°, which is 0.3° above normal and ranks 47th warmest. The average minimum of 56.9° was 1.6° on the warm side and ranked 24th mildest. High temperatures were likely reduced by several degrees during a mid-month period when a veil of smoke from western US forest fires blanketed the sky at an altitude of about 15,000 feet when skies otherwise would have been blue, especially on the 15th–16th. It is uncertain if this kept minimum temperatures somewhat warmer than they would otherwise have been. A cold front moved through from the northwest on the 18th, clearing the skies and sending temperatures plummeting. What followed was a four-day spell of temperatures that were well below average, including four nights with below-freezing temperatures at three to four Rutgers NJ Weather Network sites. While freezes resulting from cold air draining into valleys in some northern locations are not unprecedented before the end of astronomical summer, it is highly unusual for the cold to persist over four consecutive nights.

July 2020 was the hottest month on record for the Garden State since records commenced in 1895. The statewide average temperature of 78.8° was 4.2° above the 1981–2010 normal. This reading surpasses by 0.4° the previous record held jointly by 1955, 1999, and 2011. The next ten warmest months have occurred in July, with the warmest August averaging 76.8° in 2016, which is tied with July 1994 as the 11th warmest month on record. The average 88.9° maximum this past July was 5th warmest, the warmest occurring in 1999. The average minimum of 68.8° ranked second, trailing just 2013. The southern and coastal climate divisions had their warmest month on record while the northern division ranked second.

The statewide average precipitation this July was 6.79”. This is 2.22” above the 1981–2010 normal and ranks as the 15th wettest July on record. Looking at the state in quarters from north to south, the northernmost was driest, particularly the northwest. Next came a wet sector, followed by a more average one, with the southernmost quarter the wettest. Few locations received less than 4 inches, while scattered totals of more than 10 inches were found in the two wettest quarters.

In recent years, many a comment has been heard that New Jersey just does not have a spring season any more. We go right from winter to summer weather, people say. The same cannot be said for spring 2020. A seasonal summary follows at the end of this report and the individual March and April reports can be found on the state climate office website. To begin here, the talk will be of May, a month that produced both less rain and cooler temperatures than normal and included an unusual appearance of snow.

The statewide average temperature of 58.9° was 1.7° below the 1981–2010 normal. This ranked as the 40th coolest May since records commenced in 1895. April and May marked the first time since December 2017–January 2018 that consecutive months had below-average temperatures. Statewide, May precipitation averaged 2.50”. This was 1.49” below normal and ranked as the 29th driest on record.

As we gradually transition into warmer spring temperatures, it’s a good time to recap what was a disappointing season for snow lovers, along with snowplow drivers, auto body repair people, and others who profit from snowy winters.

Seasonal snow totaled 4.7” averaged across the state. This is 19.2” below the 1981–2010 average and, looking back from the 1896/96 to 2018/19 snow seasons, is 21.4” below average. This ranks as the third least-snowy winter snow season, only behind the winters of 1972/73 and 1918/19.