A Warm One
May and Spring 2010 Overview

Dr. David A. Robinson
New Jersey State Climatologist
Center for Environmental Prediction, School of Environmental and Biological Sciences/NJAES, Rutgers University
June 6, 2010

May Overview

May 2010 continued the string of anomalously warm months that began in March. This led to this spring (March-May) being the warmest observed in New Jersey since records commenced in 1895. More on spring later, but first let's take a look at May.

With an average temperature of 64.1°, this May tied for the 6th warmest on record (see table). This is 3.6° above normal. Four afternoons saw multiple locations exceeding 90°, while twelve days saw station maximums of 80°-89°. A late freeze occurred on two mornings.

Rank Year May Temp
1 2004 66.2°
2 1991 66.1°
3 1944 65.1°
4 1896 64.9°
5 1965 64.4°
6 2010 64.1°
6 1918 64.1°
6 1911 64.1°
9 1942 64.0°
10 1959 63.9°

Temperatures in central and south Jersey reached 90° on the 1st, with several stations up to 94°, while on Long Beach Island, Harvey Cedars (Ocean County) only rose to 77°. Hot weather continued the next day with Toms River (Ocean) up to 92°, while Atlantic City Marina (Atlantic) only reached 68°. The coldest afternoon of the month was the 12th, when High Point Monument (Sussex) topped out at only 41°. In the far south, West Cape May (Cape May) was as warm as 69°.

The last week of the month was quite warm, with Jersey City (Hudson) and Haworth (Bergen) up to 95° on the 26th, while Bivalve (Cumberland) got to 73°. The 31st (Memorial Day) saw an afternoon maximum of 93° in Eastampton (Burlington), with 77° reached at Harvey Cedars and West Cape May.

Minimum temperatures fell as low as the upper 20s on two mornings and were in the 30s on six others. Pequest (Warren) fell to 39° on the 5th. The 8th-13th saw at least one station in the 30s each morning. This included High Point Monument at 39° on the 8th and 33° on the 9th. The 10th saw the Monument station and Berkeley Township (Ocean) fall to 29°. The coldest morning was the 11th, when Pequest reached 27° and fifteen other northern NJ and Pinelands stations fell to or below freezing. The High Point and High Point Monument stations fell to 38° on the 12th and Basking Ridge (Somerset) to 33° on the 13th. The cold high pressure system over the state on the 11th brought the highest pressures of the month, ranging from 30.45"-30.50". The last 30s morning was the 17th when Pequest reached 39°.

May 2010 precipitation averaged 3.37" across New Jersey. This is 0.93" below normal and is the 54th driest May of the past 116. The wettest locations were Freehold (Monmouth) at 6.06", two Hamilton Township (Mercer) stations at 5.51" and 5.34", Clinton (Hunterdon) at 4.98", and Lebanon (Hunterdon) at 4.96". On the dry side, Wall Township (Monmouth) caught only 2.68", Bridgewater Township (Somerset) 2.71", Readington Township (Hunterdon) 2.74", and Sea Isle City (Cape May) 2.75".

There were six events during the month where at least one location in the state caught at least an inch of rain, plus there were two others of at least a half inch. Thunderstorms on the 3rd dumped as much as 2.22" in Morris Township (Morris) and 1.50" to 2.05" at 32 other CoCoRaHS stations. Vernon Township (Sussex) had quarter inch diameter hail. South Jersey missed out on this event. On the 12th-13th, 1.06" fell in Hillsborough Township (Somerset) with numerous stations receiving from 0.50"-0.80". Thunderstorms on the 14th brought 1.77" to Upper Deerfield (Cumberland) and 1.32" to Pennington (Mercer), along with inch and 3/8" diameter hail to Vineland (Cumberland) and Lavallette (Ocean), respectively. However, three dozen CoCoRaHS stations remained dry. Heavy rain fell across much of NJ on the 18th-19th. Little Egg Harbor (Ocean) received 2.75", Barnegat Township (Ocean) 2.52", and Folsom (Atlantic) 2.51". Many locations in north and south Jersey caught 1-2", with more in the southeast besides those listed above catching more than 2". The central and northwestern counties saw between 0.50" and 1.00".

Scattered showers on the 23rd-24th brought 0.53" to Woodstown (Salem), 0.50" to Middle Township (Cape May) and 0.41" to Rockaway Township (Morris), while areas in central and northern NJ caught nothing. Thunderstorms on the 27th brought 1.48" to Clinton and 1.46" to Lebanon in Hunterdon County. Liberty Township (Warren) received 0.41", while most other locations had under 0.50". The Monmouth County area saw 0.75" in Freehold and 0.69" in Howell on the 29th, while most other counties had 0.20" or less.

The late afternoon and early evening of Memorial Day (31st) saw a severe storm traverse the state from the Trenton (Mercer) to Freehold (Monmouth). Localized downpours brought 2.62" and 2.31" to two CoCoRaHS stations in Hamilton Township (Mercer) and 2.34" to Freehold and 2.04" to Holmdel (Monmouth). One inch diameter hail was observed in Hamilton Township.

The first half of May was rather windy. Gusts equaled or exceeded 40 mph on seven of the first fifteen days. High Point Monument (Sussex) had a 52 mph gust on the 4th, with six other stations in central and north Jersey gusting between 42-49 mph. A 40 mph gust was reached at High Point Monument on the 6th. Only light rain accompanied strong winds and the lowest pressure (29.40"-29.50") on the 8th, with some tree damage reported. Gusts of 50 mph or more were observed at Stewartsville (Warren; 54 mph), Harvey Cedars and Atlantic City Marina (both 53 mph), High Point Monument (52 mph) and Wantage (Sussex; 50 mph). Eight other stations gusted between 40-48 mph. Strong winds continued on the 9th (51 mph at High Point Monument, three stations between 42-48 mph) and 10th (41 mph at the Monument). Coastal Seaside Heights (Ocean) saw a 40 mph gust on the 14th, Wantage gusted to 49 mph on the 15th, and Seaside Heights on the 18th reported a 41 mph gust, the last of that magnitude during May.

Spring 2010 Overview

With the 5th, 1st and 6th warmest spring months (March to May, respectively) on record it is no surprise that spring 2010 was the warmest on record in the Garden State (see table). The 55.2° three-month average was 4.5° above normal, exceeded the previous warmest spring (1921) by a full half degree, and was 1.2° warmer than the 3rd warmest spring. Five of the ten warmest springs of the past 116 years have occurred in the past 20 years. The afternoon of April 7th was arguably the warmest day so early in the season on record in NJ.

Rank Year Spring Temp
1 2010 55.2°
2 1921 54.7°
3 1991 54.0°
4 1945 53.9°
5 1977 53.7°
6 2004 53.7°
7 1998 53.5°
8 1903 53.2°
9 1985 53.1°
10 2000 52.8°

Spring precipitation fell almost exclusively in the form of rain and on average totaled 15.23" across New Jersey. This is 2.83" above normal and ranks as the 12th wettest (see table). This high ranking owes most everything to March, the wettest 3rd month of the year on record. Meanwhile, April and May both came in with sub-normal totals. Severe flooding and some of the worst wind damage across the state in years accompanied a formidable mid-March nor'easter.

Rank Year Spring Prcp
1 1983 22.25"
2 1984 20.03"
3 1953 18.11"
4 1952 17.76"
5 1940 16.76"
6 1989 16.59"
7 1998 16.00"
8 1901 15.87"
9 1980 15.71"
10 1958 15.50"
11 1948 15.28"
12 2010 15.23"
13 1973 15.16"
14 2007 15.15"
15 1912 14.90"

For those seeking more detailed information on hourly, daily and monthly conditions, please visit the following Office of the NJ State Climatologist's websites:

NJ Weather and Climate Network
NJ Community Collaborative Rain, Hail and Snow Network
NJ Snow Event Reports

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Past Climate Summaries