Monthly Summaries

November was the first month since May 2020 with both averages of precipitation and temperature below 1991–2020 normals. The last drier-than-normal month was this past June while the last cooler-than-normal month was this past May. However, it’s been a while, 19 months, since the two anomalies teamed up. And dry it was, with the statewide average of 1.06” running 2.29” below normal. This ranks as the 7th driest November since records commenced in 1895. Only two other Novembers since 1936 fall in the top 10.

The statewide average November temperature of 43.9° was 1.2° below the 1991–2020 normal and ranked as the 73rd coolest of the past 127 years. This was 17.2° cooler than the mild average of this past October. The normal difference between the months is 10.2°. The average maximum was 54.5° (-0.2°, 84th coolest) and the average minimum was 33.2° (-2.3°, 47th coolest). The north averaged 41.9° (-1.2°, 74th coolest), the south 44.9° (-1.4°, 68th coolest), and the coast 46.0° (-1.3°, 70th coolest). The first Rutgers NJWxNet or NWS Cooperative station to reach the freezing point this season was Pequest (Warren County), late on the 2nd. This was the latest first freeze in NJ since at least 1900 (based on Coop records). The last location to reach freezing was West Cape May (Cape May) on the 28th, on the late side but not unusually so.

Post-tropical storm Ida. The title of this month’s report speaks to this momentous weather extreme that will forever be the defining event of this month and likely the entire year. The storm delivered the most powerful tornado to strike the Garden State since 1990, demolishing multiple homes in Gloucester County. Rainfall exceeding 3.00” per hour led to the most widespread flash flood event on record for the state, resulting in the tragic deaths of 30 individuals in central and northeastern locales. A separate report on Ida has been prepared and may be accessed in the "News" menu.

There were 29 other days of weather this month that fortunately were not as dramatic as Ida on the 1st. All told, monthly precipitation averaged 6.20” across NJ. This was 2.04” above the 1991–2020 normal and ranks as the 15th wettest September since 1895. The north, where the bulk of Ida’s rain fell, averaged 8.92”, which was 4.46” above normal and ranks 7th wettest. The south averaged 4.61”, which was 0.62” above normal and ties as the 31st wettest. Along the coast, only 3.81” fell, some 0.08” below normal and ranking 44th wettest.

Wow, what a month. July 2021 provided a never-ending cascade of weather events, including a tropical storm, a record-tying number of tornadoes, large hail, flash floods, hot days, chilly nights, smoke-filled skies, and on the last day of the month, perhaps the nicest day of the summer. The statewide average precipitation of 7.59” was 2.88” above the 1991–2020 normal and ranked 8th wettest of all Julys back to 1895. It was the wettest July since 1975 and second wettest in almost 50 years. The northern portion of the state averaged 8.16” which was 3.44” above normal. The south averaged 7.36” which was 2.62” above normal.

The average temperature of 75.8° was 0.4° above the 1991–2020 normal, but 1.9° above the 1895–2021 average. This ranked as the 24th warmest July since 1895. 13 of the 25 warmest Julys in the past 127 years have occurred since 2002. The nine July tornadoes is the most in a month since official records began in 1950. Tropical Storm Elsa was the earliest fifth storm of any season on record in the Atlantic basin. Read on for details on this potpourri of weather happenings.

Weather often varies from week-to-week and even day-to-day during the spring transition season. Such was certainly the case in spring 2021, as will be recapped later in this report. However, when it came to such “weather indecision,” May 2021 took the cake. Starting off somewhat damp with seasonable temperatures, a prolonged period of exceedingly dry weather ensued, first accompanied by cooler-than-normal temperatures and frosty mornings, and later by summer-like heat. As several wildfires broke out and soil moisture vanished, concerns of early-summer drought arose. Then along came one of the coolest Memorial Day weekends on record, accompanied by more than an average May’s worth of rain in some locations. This led to frequent decision making amongst farmers, gardeners, water resource managers, utility companies and customers, and day trippers. All were left wondering what might come next! Cicadas perhaps?

With the thermometer up and down throughout May, the statewide average temperature of 61.0° was just 0.2° below the new 1991–2020 normal. This ranked as the 47th mildest May since 1895. The average maximum of 73.0° was 0.7° above normal, while the 49.0° average minimum was 1.2° below normal. This is illustrative of a month that had many clear days and cool nights with low humidity. Despite dry conditions for most of the month, monthly precipitation came in close to normal, averaging 3.95” across NJ. This is 0.20” above normal, ranking 48th wettest of the past 127 years. Far south and west central areas were driest, while the central coast and northeast saw the most rain. Unlike last May, no snow was observed.

With March being a transitional weather and climate month, there are often pronounced differences in conditions from one day or week to the next. The third month of 2021 did not disappoint in several such respects. Swings in barometric pressure as storms and high pressure systems swung through the Northeast led to 16 days with one or more Rutgers NJ Weather Network stations gusting to 40 mph or higher, with 11 of those days exceeding 50 mph. Maximum temperatures exceeded 65° on 12 days (two days had record highs in some locations), while minimum temperatures fell below 19° on 13 days. Walpack, situated in a Sussex County valley, recorded the state’s lowest (21°) and highest (67°) temperatures on a single day (22nd) and just missed this again on the 30th. There was a two-week interval with virtually no precipitation, culminating in several wildfires on the 14th, yet five events occurred where rain accumulated to 0.98” in one or more locations. Finally, a record of sorts was tied as the statewide average snowfall totaled 0.0”, something observed eight other Marches in the past 127 years. The past two Marches are the only ones with back-to-back zero totals.

Statewide precipitation averaged 4.03”, which is 0.18” below the 1991–2020 average*. This made for the 58th wettest (70th driest) since 1895. Northern NJ was driest, coming in at 3.28” (-0.73, 48th driest), the south averaged 4.47” (+0.15”, 42nd wettest), and the coast 4.68” (+0.26”, 38th wettest). The southeast saw the most rain and northeast and central regions the least (Figure 1).

March temperature average 43.9°, which is 2.9° above the 1991–2020 average and the 14th mildest on record. The average high was 54.7° (+3.8°, 13th mildest) and average low was 33.0° (+1.8°, 19th mildest). The north averaged 41.2° (+2.4°, 19th mildest), south 45.6° (+3.2°, 13th mildest), and the coast 45.1° (+2.9°, 13th mildest).