Montana Climate Data

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

Below is a collection of Montana Climate Data and outdoor design conditions. We included an Montana 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 Montana we would consider adding to the Montana 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 Montana Manual J taken care of.

Free Manual J

MontanaElevation 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
Billings, Logan international airport357046-69162-33-26-18H2.65
Bozeman, Gallatin Field444946-108860-36-28-20H5.14
Butte, Bert Mooney airport553546-128457-47-39-31H7.86
Cut Bank Municipal airport383949-138559-38-31-23H6.13
Dillon Airport52234518660-36-28-20H4.95
Glasgow international airport229348-179164-25-18-11H3.66
Glendive Automated Weather Observation System245747-129164-22-14-7H3.74
Great Falls370747-68760-38-31-23H4.29
Great Falls international airport365847-118960-37-30-22H3.96
Havre City-Co. airport259849-189163-29-22-15H3.99
Helena Regional airport386847-88961-37-29-21H3.81
Jordan Remote Automatic Meterological Observing System266147-189363-30-23-16H3.72
Kalispell, Glacier Park international airport297248-18662-27-20-13H5.53
Lewistown Municipal airport414747-108760-35-28-20H5.32
Livingston airport465645–148760-36-28-20H4.21
Malmstrom Air Force Base (Great Falls)346548-109062-33-26-18H3.16
Miles City Municipal airport263546-129565-25-18-10H2.68
Missoula international airport31894728962-32-25-17H4.11
Sidney Muncipal airport198548-139067-9-25H3.85
Montana State Average3521.421052631647-9.666666666788.894736842161.6315789474-31.8421052632-24.5263157895-16.8421052632H4.3557894737


Montana Climate Data
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Montana Climate Data
Montana Climate Data
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