Connecticut Climate Data

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

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

Free Manual J

ConnecticutElevation 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
Bridgeport, Sikorsky Memorial airport1641158572243138L1.71
Hartford, Bradley international airport1804288872202733M2.05
Hartford, Brainard Field2042118873253238M1.82
New Haven airport (Bridgeport DD)144178473334046M1.71
New London (Bridgeport DD)104198572263239M1.71
Oxford Automated Weather Observation System7284198471233036M2.66
Waterbury (Hartford DD)8504128571222835M1.82
Willimantic Automated Surface Observation System2494298672263339M2.24
(Hartford DD)1974288871162229M1.82
Connecticut State Averages259.818181818241.36363636368.545454545585.727272727371.909090909124.27272727273137.5454545455M1.9772727273


Connecticut Climate Data
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Connecticut Climate Data
Connecticut Climate Data
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Email order number, PDF Plans, jobsite address, and square footage to