Take a look at the high temperatures from June 28, 2023. It was hot that day, Omaha hit a high of 96 degrees. However, one number probably sticks out to you. Lincoln hit 101, which is several degrees warmer than any of the surrounding cities. York, just down I-80, is 11 degrees cooler. Even Beatrice, which is further south than Lincoln, is three degrees cooler.
If you follow the weather closely, this might not be news to you. It seems like most summer days Lincoln is always a few degrees warmer than Omaha or other cities. Is there a reason for this? Is Lincoln just hotter? Is there an issue with the sensor? If there is an issue, can we change it? All of the questions you may have, and maybe not thought of, are answered right here.
First of all, let's look at what we use to record the weather. There are two types of weather stations that the NWS uses to get data and the weather data that goes to your TV screen. The first is a network of over 900 stations located at various airports across the country known as the Automated Surface Observing System (ASOS for short). This system is controlled by the National Weather Service (NWS), the Federal Aviation Administration (FAA), and the Department of Defense (DOD). These stations record the weather every minute, 24/7. Eppley Airfield, Lincoln Airport, Norfolk Regional Airport, Tekamah Municipal Airport, and Brenner Field in Falls City are ASOS stations.
Alongside ASOS stations there is the Automated Weather Observing System (AWOS for short), like ASOS stations these are located at airports across the United States. Instead of recording the weather every minute, AWOS stations record the weather every 20 minutes. AWOS stations are also recorded at airports. The following cities in our viewing area have AWOS stations: In Nebraska, there is Millard, Bennington, Fremont, Wahoo, Plattsmouth, Nebraska City, Beatrice, York, Columbus, and Wayne. In Iowa, Council Bluffs, Shenandoah, Clarinda, Red Oak, Atlantic, Harlan, Denison, and Carroll.
Basically, that is a very detailed and long-winded explanation to get to what is important for the Lincoln question, that weather stations are located at airports. So, why is this detail important? Well, not all airports are built the same, and location matters.
This is a satellite image of Eppley Airfield with the ASOS station plotted. Looks normal enough. It's off of the runways, and away from any buildings. At Eppley, there is not much interference with the station in regard to its location.
Now let's look at Lincoln: notice anything different? The station, albeit still in the grass, is located next to a giant lot. That lot is where the Sports Car Club of America (SCCA) holds its solo racing national championships. This is the answer, concrete!
What does concrete have to do with Lincoln being hotter? It has everything to do with it! Concrete is great at absorbing heat and retaining it, much better than grass or other surfaces. You might have heard of the urban heat island effect, where major cities tend to be warmer than surrounding towns. Concrete is a big factor in that, because of its high heat capacity. Likewise, at night the warmer concrete cools slower, meaning major cities are often warmer at night.
The fact that the Lincoln weather station sits right next to a giant concrete lot, likely experiences the effects of the hotter concrete, and thus the temperature is raised several degrees. Contrast that with Omaha, where the sensor is generally away from concrete and thus reflects more accurately the temperature. Another smaller factor might be the urban heat island itself. Eppley Airfield generally sits away from the core of the Omaha metro, while the Lincoln Airport is nestled into the northwest corner of the city, where the effects of the urban heat island are more felt.
So, now that we know the reason, what can we do about it? Well, nothing really. You might ask yourself, "Why not move the sensor?"
Well, that could come with its own set of problems. Records are kept in Lincoln using that sensor, if you move it to a location where it's likely cooler, you would see those records getting altered and rendered useless. So moving it is not a good idea. So for now, we just have to live with the fact that Lincoln will always appear warmer than Omaha, you can blame the concrete on that one!
