‘Urban Heat Islands’–According To The U.S. Government; + New Study Finds 96% of U.S. Temperature Stations Are “Corrupted”

The U.S. government recently unveiled the website heat.gov with its vision of achieving “a nation free from heat-related illness and death”–which is a big ask for a website.

Surprisingly, the site tackles the topic of Urban Heat Islands, and it has this to say:

‘The term “urban heat island” refers to the fact that cities tend to get much warmer than their surrounding rural landscapes, particularly during the summer. This temperature difference occurs when cities’ unshaded roads and buildings gain heat during the day and radiate that heat into the surrounding air. As a result, highly developed urban areas can experience mid-afternoon temperatures that are 15°F to 20°F warmer than surrounding, vegetated areas.’

For decades now, scientists have queried the placement of U.S. thermometer stations given this skewed warming in built-up areas. It has even led to suggestions that the observed increase in U.S. temperatures between the 1980s and the 2000s is, at least partly, attributable to negligent weather station placement.

This contention is backed up by a recent nationwide study published by the Heartland Institute which asserts that “official NOAA temperature stations produce corrupted data due to purposeful placement in man-made hot spots”.

The new study, Corrupted Climate Stations: The Official U.S. Surface Temperature Record Remains Fatally Flawed, finds that approximately 96 percent of U.S. temperature stations used to measure climate change fail to meet what NOAA considers to be “acceptable” and uncorrupted placement by its own published standards.

The detailed report was compiled via satellite and in-person survey visits to NOAA weather stations that contribute to the “official” land temperature data in the United States.

The research shows that 96% of these stations are corrupted by localized effects of urbanization — producing heat-bias because of their close proximity to asphalt, machinery, and other heat-producing, heat-trapping, or heat-accentuating objects.

Placing temperature stations in such locations violates NOAA’s own published standards (see section 3.1 here), and strongly undermines the legitimacy and the magnitude of the official consensus on long-term climate warming trends in the United States.

“With a 96 percent warm-bias in U.S. temperature measurements, it is impossible to use any statistical methods to derive an accurate climate trend for the U.S.,” said Heartland Institute Senior Fellow Anthony Watts, the director of the study. “Data from the stations that have not been corrupted by faulty placement show a rate of warming in the United States reduced by almost half compared to all stations.”

NOAA’s “Requirements and Standards for [National Weather Service] Climate Observations” instructs that temperature data instruments must be “over level terrain (earth or sod) typical of the area around the station and at least 100 feet from any extensive concrete or paved surface”, and also that “all attempts will be made to avoid areas where rough terrain or air drainage are proven to result in non-representative temperature data.”

The new report reveals the above instruction is routinely violated, and, according to H. Sterling Burnett, director of the Arthur B. Robinson Center on Climate and Environment Policy at The Heartland Institute, is evidence of two things: “First, the government is either inept or stubbornly refuses to learn from its mistakes for political reasons. Second, the government’s official temperature record can’t be trusted. It reflects a clear urban heat bias effect, not national temperature trends.”

Checking back with heat.gov, the U.S. government fully acknowledges that the urban heat island effect is indeed a thing and also that it impacts metropolitan temperatures: ‘cities create their own microclimates because they greatly alter the local landscape.’

The website then goes on to list four of the largest influences that cause cities to be hotter than their surroundings:

1) ‘Low Albedo, Heat-Storing Materials’–dark surfaces absorb more energy from sunlight than lighter, more reflective surfaces;

2) ‘Lack of Trees and Other Vegetation’–vegetation, including soil, absorb and release moisture, which requires the use of heat

3) ‘Urban Canyons & Urban Geometry’–buildings create an urban canyon effect that blocks wind flow that would otherwise provide ventilation to streets below, cooling them as well as speeding up evaporation;

4) ‘Waste Heat’–urban areas concentrate heat-emitting devices, like cars and air conditioners, over small areas. All of this heat adds up and contributes to higher air temperatures in cities.

These images from the NIHHIS Urban Heat Island Mapping Campaign in Las Cruces, NM, show how the temperature can differ greatly (by 44.5 °F) between shaded grass and exposed pavement. [David DuBois/heat.gov].

The Heartland Institutes’ new study gives examples of what it calls ‘the bias problem’.

The chart below (found on page 17 of the report) shows 30 years of data from NOAA temperature stations loccted in the CONUS.

The blue lines show recorded temperatures and the trend from stations that comply with NOAA’s published standards; the yellow lines are temperatures taken from stations that are not compliant with those standards (i.e. near artificial hot spots); and the red lines are the “official” adjusted temperature released by NOAA.

“If you look at the unperturbed stations that adhere to NOAA’s published standard–ones that are correctly located and free of localized urban heat biases–they display about half the rate of warming compared to perturbed stations that have such biases,” explained Watts.

“Yet, NOAA continues to use the data from their warm-biased century-old surface temperature networks to produce monthly and yearly reports to the U.S. public on the state of the climate. The issue of localized heat-bias with these stations has been proven in a real-world experiment conducted by NOAA’s laboratory in Oak Ridge, Tennessee and published in a peer reviewed science journal,” Watts added.

“By contrast, NOAA operates a state-of-the-art surface temperature network called the U.S. Climate Reference Network. It is free of localized heat biases by design, but the data it produces is never mentioned in monthly or yearly climate reports published by NOAA for public consumption.”


The observed increase in U.S. temperatures between the 1980s to the 2000s could be attributable, at least partly, to urbanization and negligent weather station placement.

It is unanimously agreed upon that built-up areas –our towns and cities– run hotter than rural areas, and it has also been found that 96% of NOAA temperature stations produce corrupted data due to purposeful placement in said “hot spots”.

They did always tell us that global warming was ‘man-made’…

The Heartland Institute, a free-market think tank founded in 1984, is one of the world’s leading organizations promoting the work of scientists who are skeptical that human activity is causing a climate crisis.