Climate Zone Information for North Texas

This website discusses home comfort issues as they relate to Texans living in North Texas. See the map below for a general geographic grounding. We are discussing zone 3 on this website. This climate zone is considered warm and mild in nature. Weather on any day can get wild, but on the average, our zone is described as warm and mild.

It is essential you know and understand your climate zone and the implications it has on your comfort level and the ability of your home to keep you comfortable without wasting energy.  A critical attribute of zone 3 is high humidity. Now, South Texas is much more humid, but we are impacted by humidity here in North Texas. More on this below. And North Texas is a cooling dominated climate. We spend more energy for cooling than heating. More on that later.

Here is a climate zone map of  North Texas from the 2009 IECC – International Energy Conservation Code. Cities and zone information have been added for orientation.

It is important to know, if you are visiting outside this zone, the information on this website might not be appropriate for you. Also, be careful at other websites. Make sure what you are reading makes sense to you where you live. You can find helpful information at the IECC site

Here in the United States we have huge variation in climates. We can’t get much colder than an iceberg called Minnesota. It doesn’t get much more balmy than South Texas, Southern California and South Florida. Here is Texas we can live in any of 5 climate variations. Therefore each zone has climate characteristics that must be addressed. In the south it is hot humid conditions. In the North, the big issue is nasty cold weather.

The climate you live in impacts the challenges you face to protect your home and save energy. Your climate determines  how big a moisture problem you have, how big an energy challenge you have during a heating season and/or a cooling season.

Your latitude relates to length of daylight and the inclination of the sun over the year. The location of the sun and your own solar orientation in your home and window layout impacts the solar loading of your home and your comfort level and should impact home design.

The critical issues that make a difference here are based on temperature and average humidity.

A little orientation-  an energy load for a particular climate is rated in heating degree days and cooling degree days.

The daily average temp is taken from the high temp and low temp, then averaged. That number is subtracted from 65 degrees – the chosen temperature of comparison- and that number is the degree day. If the average temperature is hotter than 65 that number is added to the list of Cooling Degree Days, and if the daily average temperature is below 65 degrees it is added to the heating degree days.

Ten days of daily average temperature of 40 degrees would give you (65-40) x 10 or 250 HDD – heating degree days. The CDD is similar but would be calculated on the temperature above 65 degrees.

Humidity needs special attention here.

Here in North Texas, we are in a cooling dominant climate- which probably does not surprise you. Humidity is another big factor to take into account in North Texas Here is a chart of average low and high relative humidity taken from average data from the DFW Airport weather reporting station over the last several years.


The daily average low (blue) and high (red) dew point with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).

The daily average low (blue) and high (red) dew point with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).

I swiped this great humidity map from  This implications of high humidity are huge. How well your home- your structure and your mechanical systems handle moisture dictates how healthy your indoor air is- how comfortable you are in your home and contributes to musty smells. You can gain a valuable perspective on moisture and humidity and dewpoint here.

Your home is unique. It is essential that changes you plan for your home reflect the climate we have in North Texas, the solar issues we face, and that solutions offered to you address these given conditions.

Beware of canned solutions and magical products. We discuss this issue here. 

Any questions or thoughts?  Add your comment below.

Stu Langley

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