Observed Changes in Interannual Precipitation Variability in the United States

Ryan D. Harp*, Daniel E. Horton

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Characterizing changes in precipitation patterns over time is critical for hydrologically dependent fields like water resource management and agriculture. Here, we explore observed trends in interannual precipitation variability using a suite of metrics that describe changes in precipitation over time. We analyze daily in situ Global Historical Climatology Network precipitation data from 1970 to present over 17 internally consistent sub-national United States domains using a regional Mann-Kendall trend test. We find robustly increasing trends in annual mean precipitation and wet day frequency for most of the central and eastern U.S., but decreasing trends in the western U.S. Importantly, we identify widespread significant trends in interannual precipitation variability, with increasing variability in the southeast, decreasing variability in the far west, and mixed signals in the Rocky Mountains and north-central U.S. Our results provide important context for water resource managers and a new observational standard for climate model performance assessments.

Original languageEnglish (US)
Article numbere2023GL104533
JournalGeophysical Research Letters
Issue number13
StatePublished - Jul 16 2023


  • GHCN
  • interannual variability
  • NCA
  • NEON
  • precipitation
  • precipitation variability

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)


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