The Iowa Environmental Mesonet (IEM) collects environmental data from cooperating members with observing networks. The data are stored and made available on this website.

IEM Daily Feature

Humidity Switch Turned On

Posted: 17 Jul 2018 05:35 AM, Views: 342
Tags:   2018  
The featured chart displays daily averaged surface mixing ratio for Ames. This value is an absolute measure of humidity that is more linear in nature than dew point and is not directly temperature dependent like relative humidity. The top panel shows this year's values along with the range of values from previous years. The bottom panel shows the daily departures from period of record averages. The departures for this year show a remarkable switch near 1 May from dry to humid conditions. It is almost like a switch was thrown and the elevated humidity has dominated since. Thankfully, a respite has arrived for Tuesday with comfortable dew point temperatures.
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Previous Years' Features
Mason City I-35 Deck, IA Webcam:
News Items  

New Webcam: Guttenberg
Posted: 26 Jun 12:22 PM

Website Updates
Posted: 31 May 02:49 PM

New AWOS: Hampton (KHPT)
Posted: 04 May 10:00 AM

New Webcam: Marengo
Posted: 27 Apr 08:42 PM

December COOP Data Uploaded
Posted: 28 Mar 02:39 PM

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Soil Temperatures

Data from the Iowa State Soil Moisture Network is found on this website and daily soil temperature averages are used to produce the highlighted analysis.


Besides point observations of precipitation, the IEM also processes gridded rainfall products made available by NOAA. This information is archived and made available in GIS ready formats.

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Current Data

The IEM combines data from participating networks into products like maps shown above and web applications to analyze the data.

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ISU Agronomy
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