New Brunswick, NJ

While the title of this report is guilty of some exaggeration, by just looking at the temperatures across New Jersey the past two Februaries you would not be far off the mark. The mildest February by far occurred in 2017 (40.4°), while this past February 2018 came in second mildest at 39.2°, just edging out 1998. This was 5.8° above the 1981–2010 mean and an impressive 8.3° above the 1895–present mean. The difference between mean periods further illustrates how Februaries in recent decades have been milder overall than earlier in the 20th century. So does the fact that February 2018 was milder than 62 of the past 123 Marches (February 2017 was milder than 70 Marches).

Not to be ignored due to February’s warmth, monthly precipitation certainly delivered in an impressive manner. The average statewide rainfall of 5.97” ranks as the third wettest on record. This is 3.17” above the 1981–2010 mean (2.87” above the period of record mean) and is the wettest February in well over 100 years.

The last month of 2017 was similar to many a month this past year. Whatever the season, weather conditions varied quite a bit from week to week. This was mainly due to an absence of atmospheric blocking in the middle and high latitudes with patterns that can lock a particular weather situation in place for multiple weeks. Thus in December we had a mild week, a snowy week, and a very cold week interspersed with transitional conditions. The one largely absent factor was precipitation, which resulted in the 10th driest December across NJ since records were established in 1895. The 1.57” of rain and melted snowfall was 2.28” below the 1981–2010 average. Snowfall averaged 8.7”, which is 3.9” above average and ranks as the 25th snowiest December on record. It was the snowiest since 2010. North Jersey averaged 8.7” (+2.1”), central areas 7.8” (+2.3”), and the south 9.1” (+4.9”). Temperatures seesawed from week to week, with the monthly statewide average of 33.6° being 1.6° below the 1981–2010 average. This ranked as the 61st coldest or 63rd mildest December on record.

The tenth month of 2017 was marked by the slow arrival of October-like conditions, including the first freezes of the season, the close-to-two week delay in the fall leaf season, and the absence of much precipitation until two late-month storms made up for lost time. Amidst all of this, October proved to be the second warmest across New Jersey since the onset of records in 1895. The 60.7° average was 6.2° above the 1981–2010 normal, trailing the 2007 record by 1.4°, but 0.9° above the now third mildest October in 1971. The month ended with a large portion of the state yet to be visited by the first freeze of the season.

Rainfall was rather limited throughout the first three weeks of the month, leading to an expansion of D0 “abnormally dry” conditions across the northern half of the state in the US Drought Monitor. It was anticipated that a portion of the north would move to a D1 “moderate drought” designation and the remainder of NJ to D0 come the October 31st weekly map (as mentioned in previous reports, the state climate office plays a significant role in making such designations). However, some welcome rain fell on the 24th, and on the 29th the largest statewide rain event since April 30, 2014, brought close to, and in some areas more than, a month’s worth of liquid in a major storm. This arrived on the 5th anniversary of Sandy and 6th anniversary of a historic early season snowstorm. When all was said and done, statewide October precipitation averaged 4.96”. This is 1.07” above average and ranks as the 25th wettest of the past 123 years.

Despite July and August typically being the wettest months of the year in New Jersey, their warmth usually results in evaporation rates exceeding rainfall. Thus, when heat ensues and rain is light for a few weeks—not uncommon in a Jersey summer—lawns, gardens, and fields require considerable irrigation to avoid wilting or browning. Such was not the case this past August and earlier in the summer, as rain was ample and quite timely in most areas and hot temperatures did not prevail for extended periods. More will be reported for the summer as a whole later in this report. For August in particular, the average of 5.06” of rain that fell across NJ was 0.96” above the 1981–2010 average. It ranked as the 41st wettest August since 1895 and the wettest since record wet conditions in 2011.

The average statewide August temperature of 71.7° was 1.3° cooler than the 1981–2010 average (tied with 1926, 1952, and 1985). It was 5.1° cooler than last year’s record warm August. Since 1895, there have been 57 cooler Augusts and 62 that were warmer, which reflects the fact that this year was only 0.2° cooler than the 1895–2017 average. Yes, Augusts have generally warmed in recent decades.