Dr. Matthew Wielicki: The Weather Stations We Never Had

How sparse thermometers and generous infilling built a global temperature story.

irrationalfear.substack.com

Clintel Foundation
Date: 11 August 2025

A central pillar of the climate-crisis narrative is simple enough to fit on a bumper sticker… today is the hottest in human history. That line only works if you accept, without question, that we have reliable, global temperature data before satellites. We do not. What we have is a patchwork of land stations concentrated in a few developed regions, a lot of ocean guesses from ship tracks, and then, later, generous statistical infilling.

Everyone agrees the 1930s were brutally hot across the United States… the Dust Bowl was a humanitarian and ecological disaster. Crops failed, soils blew away, and heat waves killed thousands. NOAA’s own retrospectives still call out 1936 as a benchmark summer, and July 1936 remains a singular month in the U.S. record.

https://www.weather.gov/arx/heat_jul36?utm

Atmospheric CO₂ at that time was roughly 310 PPM, a level derived from ice core records and widely used in NASA’s GISS datasets.

So the story we are told goes like this… yes, the U.S. was scorched in the 1930s, but the world was cooler, and only in the modern era did global temperatures rise everywhere. That story depends less on observations and more on algorithms.

https://data.giss.nasa.gov/gistemp/graphs_v4/

The global map we never measured

Before 1950, most thermometers were in the United States, Europe, and parts of the British Commonwealth. Large parts of Africa, South America, the Arctic, and the Southern Ocean had little to no routine coverage. Even the NOAA-led overview of GHCN-Daily notes how the core database is a collage of many sources with varying periods of record… that is the raw material modern analyses inherit.

Now the uncomfortable part. When there are no thermometers, you either leave grid boxes blank, or you paint numbers in from far away. HadCRUT historically left many boxes blank, explicitly avoiding interpolation, which means the “global” mean depends on where you have observations. NASA’s GISTEMP goes the other direction and spreads anomalies up to twelve hundred kilometers from a station, filling the gaps with 1200 km smoothing. Those are not trivial choices, they are the ballgame.

If you overlay the 1930s anomaly map with the station density maps, you see something obvious… warm where the thermometers were numerous, cool or neutral where coverage was threadbare. A compilation of historical station distribution between 1921 and 1950 makes the same basic point… the network was sparse and badly unbalanced.

Today’s “records,” the jet-exhaust problem

Fast forward to the present day and we add a new contaminant… urban heat and airport placement. I have shown, with time-matched photos and flight logs, how Tampa’s much hyped 100°F “record” was a five-minute artifact of a Delta jet idling beside the sensor. I walked through the same playbook in Phoenix when Sky Harbor trotted out an “August record” built on back-to-back departure plumes. If you missed those, read my recent two-parter, Jet-Fueled Lies: Tampa’s Fake Temperature Record and Jet-Fueled Lies, Phoenix Edition. They are cautionary tales about how compromised data gets laundered into national datasets and weaponized into headlines.

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In the subscriber section I lay out a simple, visual test. Using the station density maps from the early 20th century and the anomaly maps routinely cited today, I show how the warm patches of the 1930s line up with the regions where we actually had thermometers, while large cool areas coincide with regions where there was little to measure and a lot to guess. We will walk through how infilling choices, like GISTEMP’s twelve hundred kilometer spread, can turn a regional heat event into a global storyline. Then we will revisit the claim that the 1930s were globally cooler… and ask whether the evidence, once stripped of generous assumptions and modern urban contamination, is consistent with the opposite.

Dr. Matthew Wielicki

This article was published on 9 August 2025 by Dr Matthew Wielicki on his website Irrational Fear.

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