Monthly Summaries

The summer of 2018 concluded on a warm, wet note across the majority of what was a persistently green Garden State throughout the season. The warmth dated back to late June, with frequent humid conditions and abundant showers from mid-July onward. There will be more on the entire summer at the end of this report. First a look at August, with a statewide average temperature of 76.8° coming in 3.8° above the 1981–2010 average. This was the second warmest August since 1895, falling just behind 2016 by 0.1°. Nine of the 13 warmest Augusts during that 124-year interval have occurred since 2001.

Statewide, August precipitation averaged 5.63”. This was 1.53” above the 1981–2010 average and ranked as the 32nd wettest since 1895. It was the wettest August since the record wettest month in 2011. As is often seen in the summer, the majority of the precipitation fell in scattered showers and thunderstorms. This resulted in a wide range of monthly totals around the state, with some serious flash flooding occurring in several locations when moisture-ladened storms parked themselves over an area for multiple hours. Where storms missed time and time again, rainfall totals were below average. The northern NJ climate division (Hunterdon, Somerset, and Union counties northward) saw their 10th wettest August on record, with an average of 8.28” falling. This is 4.17” above average. Since 1990, only August 2011 was wetter in this division.

After an ample share of ups and downs throughout the past spring, the weather in June became rather typical for the start of summer. It was drier than average in the north and wetter than usual in the south, with the temperature close to the long-term mean. Fortunately, New Jersey entered the heart of summer with reservoirs full. However, with the onset of an apparent extended period of heat late in the month, it is certainly prudent to conserve water wisely.

The June average statewide temperature of 69.8° equaled the 1981–2010 mean, but is 1.0° above the 1895–present average. This tied with 1906 and 1967 as the 42nd mildest June on record. Precipitation averaged 3.43” across NJ, which is 0.58” below the 1981–2010 mean. This ranks as the 57th driest June, tied with 2011.

If you think it has been a long time since New Jersey experienced as chilly an April as this past one, you are correct. With snow accumulating in a storm on the 2nd to snow showers on the 30th, one was hard pressed to find many days when pleasant spring conditions could be found. Toss in two mid-month days when temperatures soared into the middle 80°s and another with strong thunderstorms delivering flash flood-producing rains, and weather-oriented heads kept spinning. However, overall, it was the persistent chill that captured the most attention, with the green up of lawns and foliage, accompanied by the blossoming of spring flowers, delayed from normal by upwards of two weeks.

Statewide, the April average temperature of 47.7° was 3.2° below the 1981–2010 mean (2.0° below the 1895–2017 mean). This ranks as the 28th coolest April since 1895 and the chilliest since 1982 (also 47.7°). The highest temperature observed in NJ was 87° at Stewartsville (Warren County) on the 14th and the coldest 16° at Walpack (Sussex) on the 11th.

April precipitation across NJ averaged 4.20”. This was 0.21” above the 1981–2010 mean (0.48” above the period-of-record mean). This was the 38th wettest April on record. Plentiful precipitation since February has eliminated drought concerns as we enter the summer water consumption season. Reservoirs and ground water levels are in good shape. However, this never means we should let our guard down and not use water in a responsible manner.

While remarkable deadly and destructive hurricanes pummeled portions of the Caribbean and southern states, September weather conditions in the Garden State were generally quiet. The most notable exceptions were the dangerous rip currents at the Jersey shore associated with the latter stages of Hurricanes Irma and Jose, which resulted in several drowning deaths and numerous water rescues. Minor to some moderate back-bay flooding and beach erosion accompanied the tumultuous surf, particularly between the 18th–21st. Otherwise, little more than some clouds and light rain reached NJ from these storms, while earlier some remnant energy and moisture from Hurricane Harvey brought one of the month’s few notable rain episodes. Dry conditions prevailed through much of the September, especially the second half. As a result, statewide precipitation averaged just 2.23”. This is 1.82” below the 1981–2010 average and was the 28th driest September since 1895.

While the first half of the month had an average temperature of about a degree below normal, September finished on a warm note. Some locations experienced three consecutive days with maximums of 90° or higher from the 23rd–25th. This backwards turn to warmth while the calendar suggested there should be a decline in temperature resulted in the month averaging 2.6° above the long-term mark. The 68.4° average made this the 10th warmest September on record. The last three Septembers and six since 2005 all fall into the top 10.

The atmosphere was in a progressive mode throughout December, which explains why no particular weather feature lingered in NJ or elsewhere across North America for too long. The seemingly day-to-day changes resulted in the statewide mean temperature of 36.4° being just 1.2° above the 1981–2010 normal. This ranks as the 28th mildest December since statewide records commenced in 1895, a far cry from last year’s record mild conditions. Despite there being seven precipitation events, one of which was mainly a carry over from November 30th, the rapid movement of these systems meant that none deposited prodigious totals in NJ. Thus 3.37” fell, which is 0.48” below average. This ranks as the 55th driest December. Monthly statewide snowfall averaged 2.0”. This is 2.1” below the 1981–2010 average and ranks 45th least snowy. The northern seven counties averaged 5.5”, the central six counties averaged 1.8”, and the eight southern counties 0.2”, all below average.