If you are looking for actual NWS COOP observations with no estimating and very little quality control done, check out this page.
This page allows you to download observed, sometimes quality controlled, and sometimes estimated once daily reports from various NWS networks including COOP. More detailed documentation exists here and should be consulted before using the data. Backend documentation exists for those wishing to script against the backend service.
Data is also available from the following states:
Publications Citing IEM Data (View All)
These are the most recent 10 publications that have cited the usage of data from this page. This list is not exhaustive, so please let us know if you have a publication that should be added.
- Durak, T. 2026, Advancing tallgrass prairie restorations through studies of invasion resistance and flower reflectance. Masters Thesis. Iowa State University https://www.proquest.com/docview/3380501736
- Islam, S. 2026, MULTI-SCALE RISK MODELING, DECISION SUPPORT, AND RISK COMMUNICATION FOR DROUGHT AND FLOOD HAZARDS. PhD Thesis. University of Iowa https://www.proquest.com/docview/3380545182
- McCarville, M., C. Marett, et al. 2026, Soybean Cyst Nematode Virulence to PI 88788 Soybean Resistance in Iowa: Selection Marches Steadily On. Plant Health Progress. https://doi.org/10.1094/PHP-04-26-0096-RS
- Marcos, F., C. dos Santos, et la. 2026, Seeding rate effects on soybean seed yield components and economic return. Crop Ecology and Physiology. https://doi.org/10.1002/agj2.70534
- Tsai, O., S. Hall, et al. 2026, Quantifying soybean biological nitrogen fixation using long-term isotope enrichment. Plant Soil. https://doi.org/10.1007/s11104-026-08810-2
- Roth, J. 2026, Water, sediment, and nutrient transport from a drained topographical depression within an agricultural field in North-Central Iowa. Masters Thesis. University of Minnesota https://hdl.handle.net/11299/102695
- Back, M. 2026, NUTRIENT CYCLING AT THE SEDIMENT-WATER INTERFACE OF RESTORED AND MANAGED FRESHWATER WETLANDS. PhD Thesis. Kent State. https://etd.ohiolink.edu/acprod/odb_etd/ws/send_file/send?accession=kent1783360102057182&disposition=inline
- McDaniel, M., C. Dutter, et al. 2026, A minimally destructive method for 2-dimensional soil and root mapping in row crops. Plant and Soil. https://doi.org/10.1007/s11104-026-08632-2
- Zhen, X. and W. Sadok. 2026, Increasing transpiration sensitivity to rising vapor pressure deficit raises U.S. spring wheat yields under current and future climates: a two-model simulation study. in silico Plants, diag013 https://doi.org/10.1093/insilicoplants/diag013
- St Cyr, M. 2026, Perennial ground covers: A mitigation strategy to nitrous oxide (N₂O) emissions for maize cropping systems. Masters Thesis. Iowa State University https://www.regenpgc.org/wp-content/uploads/2026/05/2026-05-19-StCyr-OFFICIAL-THESIS.pdf