A new analysis by The Heartland Institute – the USA-based think-tank that has previously criticized mainstream climate science – reports that the official weather station at Reno-Tahoe International Airport records higher temperatures than a nearby reference station, highlighting how station placement and surroundings can influence surface temperature measurements.
The study, titled Global Open Atmospheric Temperature System (GOATS): What Was Accomplished in Reno, compared data from the airport’s automated surface observing system (ASOS) station with an independently operated reference station located about 1.8km away.
According to the report, the ASOS station is positioned between runways and surrounded by paved surfaces and airport infrastructure, while the reference station was installed on a grassy site designed to meet stricter siting standards.
Researchers collected parallel measurements from December 2023 through nearly two full years of operation. They compared daily maximum (Tmax), minimum (Tmin) and average (Tavg) temperatures recorded during 2024 and 2025.
The results show that the airport station consistently recorded higher temperatures than the reference site.
In 2024, the ASOS station recorded daytime highs that averaged 1.35°F warmer and night-time lows that averaged 2.91°F warmer than the reference station. The daily average temperature difference was +2.13°F.
In 2025, the differences were smaller but still present, with daytime highs averaging 0.64°F higher, night-time lows 2.20°F higher and daily average temperatures 1.42°F higher than the reference measurements.
According to the report, the airport station recorded warmer night-time temperatures on more than 90% of nights in both years.
Anthony Watts, senior fellow for environment and climate at The Heartland Institute and creator of the GOATS system, said the results demonstrate how local surroundings can affect temperature readings.
“These measurements demonstrate that station placement alone can introduce a meaningful warm bias into reported temperature data,” Watts said. “When thermometers are placed near heat-retaining surfaces such as asphalt and buildings, they measure the temperature of that environment – not necessarily the broader atmosphere.”
The study attributes the larger differences in night-time temperatures to the ‘urban heat island’ effect, where surfaces such as pavement and concrete absorb heat during the day and release it overnight.
The Reno comparison follows earlier research by The Heartland Institute examining siting issues at weather stations across the USA. The authors say the side-by-side measurements in Reno provide a direct comparison under the same weather conditions.
Watts said the findings highlight the importance of evaluating station placement when analyzing long-term temperature records.
“This project provides a real-world demonstration of how microsite exposure affects the temperatures being reported,” he said.
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