Overview
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Fast Facts:
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NWS Headlines: 1 PM Monday July 27, 2026
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Temperatures & Heat Indices
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| Two Day Peak Temperatures & Heat Indices |
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| Sunday, July 26 Peak Temperatures | Monday, July 27 Peak Temperatures |
...Highest Heat Index from July 26-27...
Observations are collected from a variety of sources with varying
equipment and exposures. We thank all volunteer weather observers
for their dedication. Not all data listed are considered official.
Location Heat Idx. Time/Date Provider
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Macomb Arpt 128 F 0555 PM 07/26 AWOS
Fort Madison Arpt 125 F 0555 PM 07/26 AWOS
Burlington Arpt 121 F 0553 PM 07/26 ASOS
Keokuk Arpt 121 F 0235 PM 07/26 AWOS
Cedar Rapids Arpt 119 F 0552 PM 07/27 ASOS
Iowa City Arpt 119 F 0652 PM 07/27 ASOS
Freeport Arpt 119 F 0635 PM 07/27 AWOS
Independence Arpt 119 F 0235 PM 07/27 AWOS
Dubuque Arpt 118 F 0453 PM 07/27 ASOS
Muscatine Arpt 117 F 0515 PM 07/27 AWOS
Quad City Intl Arpt 114 F 0552 PM 07/27 ASOS
Clinton Arpt 113 F 0656 PM 07/27 AWOS
Sterling/Rock Falls Arpt 113 F 0156 PM 07/27 AWOS
Davenport Arpt 111 F 0452 PM 07/26 ASOS
Mount Pleasant Arpt 111 F 0555 PM 07/27 AWOS
Dew Point
The dew point is the temperature the air needs to be cooled to in order to achieve a relative humidity (RH) of 100%.
The higher the dew point rises, the greater the amount of moisture in the air. This directly affects how "comfortable" it will feel outside. Many times, relative humidity can be misleading. For example, a temperature of 55 and a dew point of 55 will give you a relative humidity of 100%, but a temperature of 80 and a dew point of 60 produces a relative humidity of 50%. It would feel much more "humid" on the 80 degree day with 50% relative humidity than on the 30 degree day with a 100% relative humidity. This is because of the higher dew point.
So if you want a real judge of just how "dry" or "humid" it will feel outside, look at the dew point instead of the RH. The higher the dew point, the muggier it will feel.
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| More on Dew Points Including Peak Dew Points Observed July 26-27, 2026 |
High Dew Points Duration Facts:
The six consecutive hours Cedar Rapids (CID) was 80°+ dew point was the most since August 26, 2024, and was only the 14th calendar day that such a lengthy stretch of 80°+ dew points has happened since 1995. The other summers in which this has happened since 1995 were 1995, 1999, 2001, 2005, 2016, and 2024.
The ten consecutive hours Moline (MLI) was 80°+ dew point appears to be the longest hourly duration of that high of dew point since at least 1995. The next closest stretches were 7 hours in length on July 27, 1997, July 30, 1999, and August 7, 2022. It is important to keep in mind there can be subtleties that can happen with the reporting of data in Celsius, and then depending on the archiving of the data too. But that would only account for a possible 1°F error, so no matter what, this was extremely rare for the Quad Cities.
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Environment
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| Upper level (500 mb or ~18,000 ft) weather pattern on the morning of Sunday, July 26, showing a significant ridge over the central U.S. This pattern at the climatological warmest time of the year is a perfect recipe for hot and humid weather, especially considering it also is the peak corn evapotranspiration time of year. | Upper level (500 mb or ~18,000 ft) weather pattern on the morning of Monday, July 27. The northeast quadrant of a heat dome and associated upper level ridge is well known as a precarious place to be for thunderstorms. They tend to develop where the upper atmospheric flow is strong above the leading edge of the warm and humid air. This occurred in Wisconsin and Illinois on this day. |
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| Sunday, July 26 4 PM Surface Weather Map. A warm frontal boundary had become stalled over the area, allowing for even greater pooling of extreme dew point air, as well as assisting the development of low clouds and fog on this morning. | Monday, July 26 4 PM Surface Weather Map. The boundary has shifting northeast and would serve as the focus for several hours of high impact thunderstorms in eastern Wisconsin, northeast Illinois, and Indiana. To the west of that, our area remained hot and humid. |
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| July 26, 7 PM NWS Quad Cities Weather Balloon Data. This sounding indicated a very warm and most low levels underneath steep lapse rates -- a classic signature of a widespread hot and humid air mass. This was so impressive because the potential instability, or MUCAPE, was 8,455 J/kg on this sounding. That is the 3rd highest on an observed DVN sounding (12Z or 00Z) since 1995! See to the right for the list of the highest. | DVN Highest Observed MUCAPEs on Routine Soundings. The most unstable convective available potential energy is an indication of the maximum instability within the vertical profile. It's also directly related to updraft strength, and if thunderstorms develop in these environments they are explosive and very regularly severe (often significant). |
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| July 27 Afternoon and Nighttime Satellite Geocolor Imagery. This shows the deep thunderstorms that developed across eastern Wisconsin and northeast Illinois, feeding on the high warmth and moisture that was being steered in on southwest winds over our area. |
Additional Information
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