Last updated: August 26, 2025
Article
Climate Monitoring at Fort Larned National Historic Site: Water Year 2024
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Overview
Together, climate and hydrology shape ecosystems and the services they provide, particularly in arid and semi-arid ecosystems and across the Southern Plains (Woodhouse and Overpeck 1998). Understanding changes in climate, groundwater, and surface water is key to assessing the condition of park natural resources—and often, cultural resources.
At Fort Larned National Historic Site (Figure 1), Southern Plains Inventory and Monitoring Network scientists study how ecosystems may be changing by taking measurements of key resources, or “vital signs,” year after year—much as a doctor keeps track of a patient’s vital signs. This long-term ecological monitoring provides early warning of potential problems, allowing managers to mitigate them before they become worse. At Fort Larned National Historic Site, we monitor climate, among other vital signs.
Reporting is by water year (WY), which begins in October of the previous calendar year and goes through September of the water year (e.g., WY2024 runs from October 2023 through September 2024). This web report presents the results of climate monitoring at Fort Larned National Historic Site in WY2024.
Reference: Woodhouse, C. A., and J. T. Overpeck. 1998. 2000 years of drought variability in the central United States. Bulletin of the American Meteorological Society 79(12): 2693–2714. https://doi.org/10.1175/1520-0477(1998)079%3C2693:YODVIT%3E2.0.CO;2.
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Climate and Weather
There is often confusion over the terms “weather” and “climate.” In short, weather describes instantaneous meteorological conditions (e.g., it’s currently raining or snowing, it’s a hot or frigid day), and climate reflects patterns of weather at a given place over longer periods of time (seasons to years). Climate is the primary driver of ecological processes on earth. Climate and weather information provide context for understanding the status or condition of other park resources.
Methods
A National Oceanic and Atmospheric Administration Cooperative Observer Program (NOAA COOP) weather station (Larned 2 KS #144530) is located 5.8 miles (9.3 km) east of Fort Larned National Historic Site and has been operational since 2009 (Figure 1). This station typically provides a reliable climate dataset. However, in WY2024 it was missing data on 28 days. As a substitute, climate analyses in this report use WY2024 and 30-year averages (1991–2020) of gridded surface meteorological (GRIDMET) data from the location of the visitor center. Subsequent reports may revert to the weather station as the data source, depending on future data quality.
GRIDMET is a spatial climate dataset at a 4-kilometer resolution that is interpolated using weather station data, topography, and other observational and modeled land surface data. Temperature and precipitation estimated from GRIDMET may vary from actual weather at a particular location, depending on the availability of weather station data and the difference in elevation between the location of interest and that assigned to a grid cell. Data from both the weather station and GRIDMET are accessible through Climate Analyzer.
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Results
Precipitation
Annual precipitation at Fort Larned National Historic Site in WY2024 was 24.87″ (63.2 cm), 0.86″ (2.2 cm) less than the 1991–2020 annual average. While the annual precipitation total was similar to average, monthly precipitation totals in WY2024 were variable throughout the year relative to the 1991–2020 averages (Figure 2). For example, the water year began drier than average in October and November but December received over three times its average rainfall. Wetter conditions continued into January and February followed by much drier than average levels in March and April. Precipitation totals from May through August were similar to average, except June, which received 2.95″ (7.5 cm) more than average. Drier than average conditions occurred in September.
Air Temperature
The mean annual maximum temperature at Fort Larned National Historic Site in WY2024 was 71.4°F (21.9°C), 2.4°F (1.4°C) above the 1991–2020 average. The mean annual minimum temperature in WY2024 was 44.5°F (6.9°C), 1.6°F (0.9°C) above the 1991–2020 average. Mean monthly maximum and minimum temperatures in WY2024 differed by as much as 10.4°F (5.8°C; see February as an example) relative to the 1991–2020 monthly averages (Figure 2). Mean monthly maximum and minimum temperatures were higher than average in every month except January and July.
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Drought
Reconnaissance drought index (Tsakiris and Vangelis 2005) provides a measure of drought severity and extent relative to the long-term climate. It is based on the ratio of average precipitation to average potential evapotranspiration (the amount of water loss that would occur from evaporation and plant transpiration if the water supply was unlimited) over short periods of time (seasons to years). The reconnaissance drought index for Fort Larned National Historic Site indicates that for the fourth consecutive year WY2024 was drier than the long-term average from the perspective of both precipitation and potential evapotranspiration (Figure 3).
Reference: Tsakiris G., and H. Vangelis. 2005. Establishing a drought index incorporating evapotranspiration. European Water 9: 3–11.
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Report Citation
Authors: Kara Raymond, Andy Ray
Raymond, K., and A. Ray. 2025. Climate and Weather Monitoring at Fort Larned National Historic Site: Water Year 2024. Southern Plains Network, National Park Service, Pecos, New Mexico.