2020 Weather In Review: Hopewell Furnace National Historic Site

Hopewell Furnace Cast House (credit: Flickr / hithisisdanielle / CC-BY_NC 2.0)

In order to better understand ecosystem health in national parks, the Mid-Atlantic Inventory and Monitoring Network measures ecosystem "vital signs" across the Mid-Atlantic region. One of those vital signs is weather and climate. Below is a summary of 2020 weather conditions at Hopewell Furnace National Historic Site.

This brief provides county-scale weather data averaged from all of the counties surrounding the park. These counties include Berks and Chester counties, PA. 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 2020 weather placed in the context of long-term climate (i.e. how did 2020 compare to a "normal" year?).

2020 Summary

In all, 2020 was extremely warm and precipitation was also above normal. The year ended as the 3^rd warmest and 22^nd wettest on record for the park. Weather data collected from surrounding areas also indicate that annual average temperature and annual total precipitation have both increased over the last century (+0.21 °F per decade and +0.39 inches per decade, respectively).

Temperature

In total, 2020 was the 3^rd warmest year ever recorded at the parks — all seasons were very warm except for the spring (Figure 1). Ten months had higher than normal temperatures with January, February, and March all being more than 6.0 °F above long-term averages (Table 1).

Figure 1. Seasonal and annual temperature rankings for Berks and Chester counties, PA. 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.

_{Table 1. Monthly and annual average temperature and departure from long-term averages. Departures from average show how different 2020 was compared to relevant averages from 1895-2019.}

Month/Year	Average temperature (°F)	Departure from long-term average (°F)
January	35.4	+6.7
February	38.3	+8.2
March	45.5	+6.4
April	48.4	-1.6
May	58.9	-1.7
June	70.8	+1.7
July	78.3	+4.5
August	74.9	+3.1
September	65.3	+0.3
October	55.6	+2.1
November	47.9	+5.4
December	35.1	+2.8
2020	54.5	+3.2

Precipitation

It all, 2020 was the 22^nd wettest year recorded at the park (Figure 2). Over the year, a total of 51.1 inches of precipitation fell, almost 6 inches more than the long-term average (Table 2).

Figure 2. Seasonal and annual precipitation rankings for Berks and Chester counties, PA. 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.

_{Table 2. Monthly and annual total precipitation and departure from long-term averages. Departures from average show how different 2020 was compared to relevant averages from 1895-2019.}

Month/Year	Total precipitation (in.)	Departure from long-term average (in.)
January	3.4	0
February	2.7	-0.3
March	3.8	+0.1
April	4.7	+1.0
May	3.2	-0.8
June	3.3	-0.8
July	5.6	+1.1
August	8.7	+4.2
September	3.6	-0.4
October	3.6	+0.1
November	3.4	+0.1
December	5.1	+1.5
2020	51.1	+5.8

Temperature and Precipitation Trends
(1895-2020)

Data for Berks and Chester counties, PA indicate that annual average temperature has increased approximately +0.21 °F per decade and annual total precipitation has increased approximately +0.39 inches per decade since 1895 (Figure 3).

National Park Service scientists have forecast future changes in climate too. Models estimate that by 2100, annual average temperature at the park will increase by 3.1–9.0 °F (from a best-case to worst-case scenario, respectively). Annual total precipitation is expected to increase by 7–14% (see Gonzalez et al., 2018 for details).

Figure 3. Annual average temperature (°F) and annual total precipitation (in.) for Berks and Chester counties, PA, from 1895–2020. Dashed lines represent linear estimates of change.

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.

The Mid-Atlantic Network's Weather and Climate monitoring program can be found here.

For more information, contact Mid-Atlantic Network Biologist, Jeb Wofford or Hopewell Furnace Natural Resource Manager, Amy Ruhe.