Counties in Iowa by annual precipitation
Clayton County had the highest annual precipitation of 99 counties in 2020, at 39.22 inches. Sioux County had the lowest, at 17.5 inches. The median was 30.2 inches and the figure for Iowa was 29.28 inches. Source: NOAA National Centers for Environmental Information.
Map of counties, 2020
- Under 22
- 22 to 25
- 25 to 30
- 30 to 34
- 34 to 36
- 36 and over
Top 40 counties, 2020
Full ranking
Other periods
About this ranking
Total precipitation from January to December, in inches: rain plus the water content of snow and other frozen precipitation. NOAA computes it from its climate divisional dataset (nClimDiv): station readings interpolated onto a 5 km grid and averaged over the area.
Values are area averages, not the reading at one weather station. NOAA revises the last two years every month.
Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.
How to cite
NOAA National Centers for Environmental Information, Climate at a Glance. NOAA Climate at a Glance, January to December precipitation, counties. From the NOAA Monthly U.S. Climate Divisional Database (nClimDiv), doi:10.7289/V5M32STR. https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping. Retrieved 2026-10-12.Citation styles
APA 7
NOAA National Centers for Environmental Information. (2026). NOAA Climate at a Glance, January to December precipitation, counties (Counties in Iowa by annual precipitation, 2020) [Data set]. Retrieved October 12, 2026, from https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping
MLA 9
NOAA Climate at a Glance, January to December precipitation, counties, Counties in Iowa by annual precipitation, 2020. NOAA National Centers for Environmental Information, 6 Oct. 2026, https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping. Invokely, https://invokely.ai/rankings/annual-precipitation/iowa-counties?period=2020. Accessed 12 Oct. 2026.
Chicago (author-date)
NOAA National Centers for Environmental Information. 2026. NOAA Climate at a Glance, January to December precipitation, counties. Counties in Iowa by annual precipitation, 2020. Dataset. Accessed October 12, 2026. https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping. Also distributed by Invokely, https://invokely.ai/rankings/annual-precipitation/iowa-counties?period=2020.
Harvard
NOAA National Centers for Environmental Information (2026) NOAA Climate at a Glance, January to December precipitation, counties, Counties in Iowa by annual precipitation, 2020 [Dataset]. Available at: https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping, via Invokely: https://invokely.ai/rankings/annual-precipitation/iowa-counties?period=2020 (Accessed: 12 October 2026).
BibTeX
@misc{noaa_counties_in_iowa_by_2020,
author = {{NOAA National Centers for Environmental Information}},
title = {{NOAA Climate at a Glance, January to December precipitation, counties: Counties in Iowa by annual precipitation, 2020}},
year = {2026},
howpublished = {Data set},
url = {https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping},
urldate = {2026-10-12},
note = {Accessed via Invokely, https://invokely.ai/rankings/annual-precipitation/iowa-counties?period=2020. Publisher attribution: NOAA National Centers for Environmental Information, Climate at a Glance. NOAA Climate at a Glance, January to December precipitation, counties. From the NOAA Monthly U.S. Climate Divisional Database (nClimDiv), doi:10.7289/V5M32STR. https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping. Retrieved 2026-10-12.},
}
RIS
TY - DATA
AU - NOAA National Centers for Environmental Information
TI - NOAA Climate at a Glance, January to December precipitation, counties: Counties in Iowa by annual precipitation, 2020
PY - 2026
DA - 2026/10/06
PB - NOAA National Centers for Environmental Information
DB - Invokely
UR - https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping
L2 - https://invokely.ai/rankings/annual-precipitation/iowa-counties?period=2020
Y2 - 2026/10/12
N1 - Accessed via Invokely, https://invokely.ai/rankings/annual-precipitation/iowa-counties?period=2020.
N1 - Publisher attribution: NOAA National Centers for Environmental Information, Climate at a Glance. NOAA Climate at a Glance, January to December precipitation, counties. From the NOAA Monthly U.S. Climate Divisional Database (nClimDiv), doi:10.7289/V5M32STR. https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/mapping. Retrieved 2026-10-12.
ER -
Use this data in your AI agent
Invokely serves this figure to AI assistants through MCP and to code through a REST API, with the source and citation attached. Ask your assistant:
Rank Counties in Iowa by annual precipitation using official data, and cite the source.
rank_places {"indicator":"precipitation_annual","level":"province","within":"Iowa","limit":10}
GET https://invokely.ai/api/v1/rank?indicator=precipitation_annual&level=province&within=Iowa&limit=10Questions
Which county has the highest annual precipitation?
Clayton County, with 39.22 inches in 2020, according to NOAA National Centers for Environmental Information.
Which county has the lowest annual precipitation?
Sioux County, with 17.5 inches in 2020.
Where does this ranking come from?
Every value comes from one source and one period, so the places are comparable: NOAA National Centers for Environmental Information, NOAA Climate at a Glance, January to December precipitation, counties. Retrieved 2026-10-12.
Annual precipitation: other rankings
Counties in Iowa: more rankings
- Social vulnerability score (FEMA National Risk Index)
- Expected annual loss from natural hazards (FEMA National Risk Index)
- Highest daily Air Quality Index (US EPA)
- National Risk Index score (FEMA)
- Real GDP growth
- Gross domestic product (GDP), US dollars
- GDP per capita, US dollars
- Business revenue: utilities (Economic Census)