New Brunswick, NJ

There are years when many say that New Jersey didn’t experience “classic” fall weather. This October is not one of those years, as the month included rain, wind, and coastal flooding from the persistent remnants of a hurricane, many locations received their first frost and freezing temperatures to end the growing season, and there were days with a cloud-free deep-blue sky. October certainly showed its true fall colors.

October temperatures averaged 54.1° across NJ. This is 1.3° below the 1991–2020 normal and was the coolest October since 2009. It was the 57th coolest (tied with 4 other years) of the 128 since 1895. The average high was 64.5° which is 1.3° below normal and is the 48th coolest (tied with 3 years). The average low of 43.6° is 1.3° below normal and ranks 65th coolest (tied with 4 years). Northern NJ averaged 52.1° (-1.2°, 59th coolest [tied with 2 years]), southern 55.1° (-1.4°, 56th coolest [tied with 3 years]), and coastal 56.6° (-1.0°, 70th coolest [tied with 1 year]).

Rainfall was abundant, averaging 6.45” statewide. This is 2.26” above normal and ranks 10th wettest on record. It was the wettest since the record October 2005. Ten different decades are found in the top 15 years. The north averaged 5.88” (+1.43”, 21st wettest), south 6.75” (+2.72”, 6th wettest), and coast 7.53” (+3.44”, 3rd wettest). Coastal Monmouth, Ocean, and Atlantic counties were wettest, coming in at two to three times normal totals. While coming in close to normal, the driest areas were in the north central, far southern, and southwest regions.

Following a hot and dry summer, the questions of the day in September were when the temperature would begin to cool and would more abundant rainfall arrive. Signs of a rainfall resurgence were mixed, with drought conditions diminishing in spots but worsening in others. The temperature answer came in almost a flash on the 22nd (the first day of astronomical fall!) when a powerful cold front sent the thermometer quickly downward with an early-fall-like pattern arriving and remaining through month’s end.

September temperatures averaged 67.8° across NJ. This is 0.9° above the 1991–2020 normal and ties as the 22nd mildest September since statewide records commenced in 1895. The average high temperature was 78.2°, which is 1.0° above normal and tied for 23rd warmest. The average low was 57.3°, 0.7° above normal and ranking 23rd warmest. North Jersey came in at 65.7° (+0.8°, tied for 23rd warmest), the south 69.0° (+0.9°, tied for 21st warmest), and the coast 69.7° (+1.0°, 15th warmest).

NJ precipitation averaged 3.16” for September, which is 1.00” below normal and ranks as the 57th driest of the last 128 years. The north was wettest at 3.64”. This is 0.82” below normal, though ranks as just the 67th driest. The south came in with 2.86” (-1.13”, 51st driest) and the coast 2.98” (-0.91”, 57th driest).

When it comes to recent hot Julys in New Jersey, the beat goes on. This year the heat was joined by quite limited precipitation, something not often seen in recent years. The statewide average temperature of 78.1° was 2.7° above the 1991–2020 normal, ranking 6th warmest since records commenced in 1895. Eight of the ten warmest Julys have occurred since 2010, leaving only 1955 and 1999 as top-ten outliers. The statewide average maximum was 88.6° (+2.9°, 6th warmest) and the minimum 67.5° (+2.4°, 4th warmest). Northern counties averaged 75.9° (+2.2°, 9th warmest), southern counties 79.5° (+3.0°, 3rd warmest), and coastal areas 78.8° (+2.6°, tied as 4th warmest).

Statewide July precipitation averaged 2.19”, which is 2.52” below normal, ranking as the 13th driest on record. Of the top 15, only two have occurred this century. The north averaged 2.03” (-2.69”, 14th driest), south 2.30” (-2.44”, 14th driest), and coast 2.16” (-2.22”, 17th driest). The central portion of the state was driest, with less than 2.00” accumulating, and under an inch in the driest areas. Closer-to-normal totals were found in the northwest, northeast, and southwest. At month’s end, portions of central NJ were classified as being in moderate drought (D1) on the weekly U.S. Drought Monitor map. This denotes conditions not seen more than once every five to ten years. Surrounding central and northern areas were considered abnormally dry (D0), as was the southeast corner of the state. This all coincides quite well with the most pronounced precipitation deficits of the past month.

Many across NJ wondered if the incessant back and forth of weather conditions from early spring into May would ever cease and the more consistent warmth of late spring would arrive and persist. It took time this year, with a cool, damp start to May that included a nine-day interval of almost continuous onshore easterly flow. Come mid-month the seasonal transition was finally complete, and daytime highs mostly remained above 70° away from the coast and higher elevations. This included two episodes where temperatures exceeded 90°. Whether it was cool or warm, rainfall was rather plentiful through most of the month. Seven events produced an inch or more at multiple locations, two of which found some spots exceeding 3.00”.

The statewide average temperature was 63.3°. This is 2.1° over the 1991–2020 normal and ties as the 14th mildest May since 1895. The average maximum of 73.6° was 1.3° above normal and ranked 35th mildest while the average minimum of 53.0° was 2.8° above normal, ranking 7th mildest. Regionally, the north division came in at 62.0° (+2.1°, 15th mildest), the south 64.3° (+2.1°, tied with two others at 13th), and coast 62.4° (+1.4°, tied with one other at 20th).

Rainfall averaged 5.37” across NJ. This is 1.62” above normal and ranks as the 23rd wettest May of the past 128 years. Even with the Highlands being somewhat dry, the north was wettest at 5.98” (+1.96”, 18th wettest). The south averaged 5.03” (+1.43”, 25th), despite the far south being on the dry side. The coast came in with 4.77” (+1.26”, 26th).