Iowa Climate Data

We offer an Iowa Manual J for $79 in 4-6 hours.  We can also offer Iowa Manual S $79 and Iowa Manual D $99.

Below is a collection of Iowa Climate Data and outdoor design conditions. We included an Iowa state average of each category at the bottom of the Manual J climate data table. We created this to allow an easy to use free resource for Manual J professionals to use on jobsites, in the field, and while calculating Manual J heat loss and heat gain reports. If you have a custom set of data from Iowa we would consider adding to the Iowa Climate Data table simply email it to

We can also create a Manual J using climate data from the tables below. Email pdf plans, jobsite address, and square footage to and we will get your Iowa Manual J taken care of.

Free Manual J

IowaElevation in FeetLatitude North DegreesHeating 99% Outdoor Dry BulbCooling Outdoor Air 1% Dry BulbCooling Outdoor Air Coincident Wet BulbCooling Design Grains 55% Relative Humidity IndoorsCooling Design Grains 45% Relative Humidity IndoorsCooling Design Grains 45% Relative Humidity IndoorsDaily RatingHeating Design Days 65 degrees/Colling Design Days 50 degrees Ratio
Ames Municipal airport9554218875404753M2.08
Ankeny Regional airport9024209174323946M1.73
Boone Municipal airport11614209077495663M1.99
Burlington Municipal airport7024119076404754M1.6
Cedar Rapids Municipal airport87342-48975374451M2.22
Charles City112543-38876495663M2.44
Clinton Municipal airport Automated Weather Observation System7094208874344147M2.2
Council Bluffs (Omaha, NB, DD)125341–39175374450M1.76
Davenport Municipal airport8504218875435057M1.99
Des Moines international airport96542-29075374451M1.84
Dubuque Regional airport107942-38673334047M2.56
Estherville Municipal airport131643-68874333946M2.75
Fair Field Municipal airport8014139178546067M1.67
Fort Dodge Automated Weather Observation System116543-68874333946M2.48
Iowa City66141–68976455258M1.69
Keokuk Municipal airport6734089178525966M1.4
Marshall Town Municipal airport9714208875414855M2.26
Mason City Municipal airport122443-88874323946M2.84
Newton 953 41 –59174303743M2.04   
Ottumwa Industrial airport8464109075384552M1.75
Sioux City, Sioux Gateway airport110242-49074344047M2.14
Storm Lake149043-49074334047M2.03
Waterloo Municipal airport87943-68974323946M2.39
Webster City11224209177515865M2.02
Iowa State Average1001.437542.84375-0.233333333387.9687574.4062540.967741935546.3762554.6774193548M2.0561290323
Iowa Climate Data
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Iowa Climate Data
Iowa Climate Data
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Email order number, PDF Plans, jobsite address, and square footage to