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2019 Weather In Review: Delaware Water Gap National Recreation Area

Dark storm clouds gathering over the Delaware River.
Delaware River (Nicholas A. Tonelli, CC by 2.0)

In order to better understand ecosystem health in national parks, the Eastern Rivers and Mountains Network measures ecosystem "vital signs" in select national parks in West Virginia, Pennsylvania, New Jersey, and New York. One of those vital signs is weather and climate. Below is a summary of 2019 weather conditions at Delaware Water Gap National Recreation Area.

Information in this brief represents county-scale weather data averaged from all of the counties surrounding the park. These counties include Monroe, Northampton, and Pike counties, Pennsylvania and Sussex and Warren counties, New Jersey. Individual weather station data may vary from what is reported here. Data are available from the National Climate Data Center.

Weather vs. Climate

First of all, what is the difference between weather and climate? Weather consists of the short-term (minutes to months) changes in the atmosphere. Weather is what is happening outside at this very moment, be it rain, snow, or just a warm sunny day. Climate is what you expect to see based on long-term patterns of over 30 years or more. An easy way to remember the difference is that climate is what you might expect, like a hot summer, and weather is what you get, like a warm rainy day.

The following information includes a discussion of 2019 weather placed in the context of long-term climate (i.e. how did 2019 compare to a "normal" year?).

2019 Summary

In all, 2019 was very wet and warm. The year ended as the 14th wettest and 15th warmest since 1895. Weather data collected from surrounding areas from 1895–2019 show increasing trends in annual average temperature (+0.26 °F per decade) and annual total precipitation (+0.40 inches per decade).

Temperature

In total, 2019 was the 15th warmest year at the park since 1895, and all seasons were warmer than long-term averages (Figure 1). Ten months had higher than normal temperatures, with February, April, July, September, and October all being more than 3 °F above normal (Table 1).

Figure 1. Average temperature rankings for counties surrounding the recreation area. The figure shows that the spring and summer were "much above normal" and that autumn and winter were "above normal." In total, the year was "much above normal."
Figure 1. Seasonal and annual temperature rankings for counties surrounding the park. An arrow at the top of the figure would represent the warmest year/season on record (since 1895); at the bottom, the coldest year/season on record.
Month/Year Average temperature (°F) Departure from
long-term average (°F)
January 26.3 +1.8
February 29.4 +3.7
March 34.4 -0.6
April 50.5 +4.1
May 59.1 +2.0
June 66.0 +0.6
July 73.9 +3.8
August 70.1 +2.0
September 64.3 +3.1
October 53.7 +3.4
November 36.9 -2.3
December 30.5 +2.0
2019 49.6 +2.0

Table 1. Monthly and annual average temperature and departure from long-term averages. Departures from average show how different 2019 was compared to relevant averages from 1895-2018.

Precipitation

In total, 2019 was the 14th wettest year in the park since 1895 (Figure 2). By the end of the year, the area received 56.4 inches of precipitation — 10 inches above the long-term average (Table 2).

Figure 2. Average precipitation ranking for counties surrounding the recreation area. In all, the year was "much above normal" for precipitation.
Figure 2. Seasonal and annual precipitation rankings for counties surrounding the park. An arrow at the top of the figure would represent the wettest year/season on record (since 1895); at the bottom, the driest year/season on record.
Month/Year Total precipitation (in.) Departure from
long-term average (in.)
January 5.3 +2.0
February 2.8 -0.2
March 3.6 -0.1
April 5.5 +1.6
May 9.0 +5.0
June 4.9 +0.6
July 7.0 +2.4
August 3.7 -0.7
September 1.2 -3.0
October 7.2 +3.5
November 2.5 -1.1
December 3.7 0.0
2019 56.4 +10.0
Table 2. Monthly and annual total precipitation and departure from long-term averages. Departures from average show how different 2019 was compared to relevant averages from 1895-2018.

Temperature and Precipitation Trends
(1895-2019)


Data from 1895–2019 for counties surrounding the park show increasing trends in annual average temperature (+0.26 °F per decade) and annual total precipitation (+0.40 inches per decade; Figure 3).
Figure 3. Line graph of annual average temperature (°F) and annual total precipitation (in.) for counties surrounding the recreation area from 1895–2018. showing increasing trends for both parameters.
Figure 3. Annual average temperature (°F) and annual total precipitation (in.) for counties surrounding the park from 1895–2019. Dashed lines represent linear trends.

Climate Change

Today's rapid climate change challenges national parks in ways we've never seen before. Wildlife migrations are altered, increasingly destructive storms threaten cultural resources and park facilities, habitat is disrupted—the list goes on. Click here to discover how climate change is affecting our nation's treasures, what the National Park Service is doing about it, and how you can help.

For more information, contact Mid-Atlantic Network Biologist, Jeb Wofford or Eastern Rivers and Mountains Network Program Manager, Matt Marshall.

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Delaware Water Gap National Recreation Area

Last updated: February 21, 2020