Cold Conroe explained

from Google maps

It seems like every time we show the morning lows, Conroe looks to be the coldest spot around and sometimes colder than ten degrees than other places nearby, like Tomball and Huntsville. For instance, this morning Conroe came in at 48° while Huntsville reported 61° and Tomball reported 53°.

You can see from the cover map, also below, that the airport (the official reporting station) is surrounded by plenty of trees which certainly plays a role. The Urban Heat Island effect occurs across much of Harris County.

from Google maps

We have tackled this issue before and Anthony Yanez blogged about it in 2012. Part of the reasoning for the cooler temperature at the airport is this:

Weather station KCXO, Conroe airport, is in a rurally wind-protected, somewhat bowl-shaped locale in relation to the surrounding topography. This layout allows winds to go calm many nights, especially in the cooler months. This equates to more efficient radiative cooling....The geography can also create a “drainage effect” where cool air (sinking) flows into the weather station....The National Weather Service states the gauge is calibrated and maintained properly. The complete story is right here.

But what about nearby stations?

Now with so many home and business weather stations uploading daily reports online, I took a minute to compare nearby locations to this morning’s CXO report of 48°. The airport still came in slightly cooler, but not by much. Take a look:

Conroe is cool, but so are nearby locations!

Of all these spots, the airport does have the highest elevation at 243′, but the other locals are in the 185′ range and Cut and Shoot is almost the same at 233′ -- and their low pretty well matched CXO. So elevation may play some role here and the closer you get to Lake Conroe you’ll likely find slightly warmer temperatures on any given morning. Still, a range of 48 to 50° for the morning low is spot on. So the daily CXO morning low that you see is likely a very good gauge for that area.

We can’t make a blanket statement with data from just one day. Still, this was a good morning to compare as skies were clear everywhere and winds calm. The Conroe Airport may report in as the coolest spot around but the greenery of all those livable forests to the north of Houston seems to play a significant role in keeping much of Montgomery County cool.

Rather than trying to explain why Conroe is so cool, perhaps we should be asking why Huntsville is so warm. That reporting station is from the airstrip just a few hundred feet from I-45.

from Google maps


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About the Authors:

KPRC 2's chief meteorologist with three decades of experience forecasting Houston's weather.