2023 Weather in Review: Johnstown Flood National Memorial

The Unger House

NPS photo

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 2023 weather conditions at Johnstown Flood National Memorial.

This brief provides county-scale weather data from Cambria County, PA, including data from 1895–2023 (i.e., period of record). Data and analyses herein are courtesy of the National Oceanic and Atmospheric Administration's (NOAA) Climate at a Glance Program.

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 2023 weather placed in the context of long-term climate (i.e., how did 2023 compare to a "normal" year?).

2023 Summary

In all, 2023 was a very warm year with total precipitation that was close to normal. The year ended as the 4^th warmest and 59^th driest on record. Data indicate that over the long term, annual average temperature and annual total precipitation have both increased (+0.1°F per decade and +0.45 inches per decade, respectively).

Temperature

In total, 2023 was warmer than normal and ranked as the 4^th warmest year ever recorded at the park. Seasonally, the fall and winter were particularly warm (Figure 1). Nine months had higher than normal temperatures with January, February, and December all being at least 8°F above long-term averages (Table 1).

Figure 1. Seasonal and annual temperature rankings for Cambria County, 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. Winter = Jan–Mar, Spring = Apr–June, Summer = July–Sept, Autumn = Oct–Dec.

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_{Table 1. Monthly and annual average temperature and departure from long-term averages. Departures from average show how different 2023 was compared to relevant averages from 1895-2022.}

Month/Year	Average temperature (°F)	Departure from long-term average (°F)
January	34.0	+9.5
February	34.9	+9.0
March	35.6	+0.7
April	49.5	+3.7
May	54.6	−2.1
June	62.1	−2.6
July	70.0	+1.2
August	67.2	+0.2
September	61.3	+0.8
October	51.9	+2.3
November	38.0	−0.5
December	36.6	+8.0
2023	49.6	+2.5

Precipitation

In total, precipitation for the year was close to normal, but seasonal precipitation was variable. The spring was very dry and the summer was quite wet (Figure 2). The year ended as the 59^th driest on record. In all, 43.2 inches of precipitation fell, about 0.8 inches less than the long-term average (Table 2).

Figure 2. Seasonal and annual precipitation rankings for Cambria County, 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. Winter = Jan–Mar, Spring = Apr–June, Summer = July–Sept, Autumn = Oct–Dec.

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_{Table 2. Monthly and annual total precipitation and departure from long-term averages. Departures from average show how different 2023 was compared to relevant averages from 1895-2022.}

Month/Year	Total precipitation (in.)	Departure from long-term average (in.)
January	4.54	+1.19
February	2.43	−0.42
March	3.13	−0.66
April	2.69	−1.03
May	2.36	−1.88
June	4.40	−0.15
July	6.08	+1.70
August	5.61	+1.74
September	3.16	−0.47
October	3.78	+0.61
November	2.22	−0.94
December	2.76	−0.47
2023	43.16	−0.79

Temperature and Precipitation Trends
(1895-2023)

Data for Cambria County, PA indicate that annual average temperature has increased approximately +0.1°F per decade and annual total precipitation has increased approximately +0.45 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 3.2–9.4°F (from a best-case to worst-case scenario, respectively). Annual total precipitation is expected to increase by 6–12% (see Gonzalez et al., 2018 for details).

Figure 3. Annual average temperature (°F) and annual total precipitation (in.) from 1895–2023 for Cambria County, PA. 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. Go to the NPS Climate Change site 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. Data included in this article were obtained from NOAA's NClimDiv dataset (version v1.0.0-20240105).