Last updated: August 26, 2025
Article
Climate and Water Monitoring at Pecos National Historical Park: 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 in the American Southwest 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 Pecos National Historical Park (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 Pecos National Historical Park, we monitor climate and groundwater, among other vital signs.
Groundwater conditions are closely related to climate conditions. Because they are better understood together, we report on climate in conjunction with water resources. 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 and groundwater monitoring at Pecos National Historical Park 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 (Pecos National Monument #296676) has been operational at Pecos National Historical Park since 1916 (Figure 1). The station typically provides a reliable climate dataset. However, in WY2024 it was missing data on 241 days. As a substitute, climate analyses in this year’s report use WY2024 and 30-year averages (1991–2020) of gridded surface meteorological (GRIDMET) data from the location of the station. Subsequent reports may revert to the weather station as the data source, depending on the completeness and quality of future data.
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 weather station and GRIDMET are accessible through Climate Analyzer.
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Results
Precipitation
Annual precipitation at Pecos National Historical Park in WY2024 was 18.87″ (47.9 cm), 2.78″ (7.1 cm) more than the 1991–2020 annual average. Overall precipitation during the cool season (October–March) was 5.16″ (13.1 cm), only 0.07″ (0.2 cm) higher than the long–term average (Figure 2). In contrast, the warm season (April–September) was wetter than average by 2.71″ (6.9 cm). This surplus is due to a wet monsoon season (June–August), but September was substantially drier than average.
Air Temperature
The mean annual maximum temperature at Pecos National Historical Park in WY2024 was 66.5°F (19.2°C), 0.7°F (0.4°C) above the 1991–2020 average. The mean annual minimum temperature in WY2024 was 36.1°F (2.3°C), 1.8°F (1.0°C) above the 1991–2020 average. Mean monthly maximum and minimum temperatures in WY2024 differed by as much as 5.1°F (2.8°C; see June as an example) relative to the 1991–2020 monthly averages (Figure 2). Mean monthly maximum temperatures were similar to or above the 1991–2020 averages in all months except January and March. Mean monthly minimum temperatures were above the 1991–2020 averages in all months.
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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 Pecos National Historical Park indicates that WY2024 was wetter than the long-term average for the third consecutive year 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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Groundwater
Groundwater is one of the most critical natural resources of the American Southwest and Southern Plains. It provides drinking water, irrigates crops, and sustains rivers, streams, and springs throughout the region.
Methods
Pecos National Historical Park groundwater is monitored in two wells (Figure 1). The New Mexico Bureau of Geology and Mineral Resources began monitoring both wells in 2020. The well at the trading post (WL-0206) is monitored annually, after previously being monitored continuously and the well at the Glorieta Battlefield Trail (WL-0207) is also monitored annually. The data are available at the
Healy Collaborative Groundwater Monitoring Network.
Results
Groundwater levels in WY2024 were stable and relatively shallow (Table 1 and Figure 4). The mean depth to water at WL-0206 was 41.33 feet below ground surface (ft bgs; 12.60 m bgs), slightly higher than the previous water year. The depth to water at WL-0207 was 34.14 ft bgs (10.41 m bgs), slightly lower than the previous measurement.
Table 1. Groundwater monitoring results in water year (WY) 2024, Pecos National Historical Park (amsl = above mean sea level; bgs = below ground surface).
| State Well Number | Location | Wellhead Elevation (ft amsl) |
Mean Depth to Water (ft bgs) |
Mean Water Level Elevation (ft amsl) |
Change in Elevation from WY2023 (± ft) |
|---|---|---|---|---|---|
| WL-0206 | Trading Post | 6,833.00 | 41.33 | 6,791.67 | +0.09 |
| WL-0207 | Glorieta Battlefield Trail | 7,330.00 | 34.14 | 7,295.86 | −0.01 |
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Report Citation
Authors: Kara Raymond, Andy Ray
Raymond, K., and A. Ray. 2025. Climate and Water Monitoring at Pecos National Historical Park: Water Year 2024. Southern Plains Network, National Park Service, Pecos, New Mexico.