Polymarket temperature markets go poof — The Autodidacts

2026-05-18<br>On May 17th, a trader bet ~$20 at 1c per share (implied 1% probability) on the wrong bucket for Mexico City temperature, and then bet again. That bucket won, and ~$50 turned into ~$5000.<br>On May 17th, Polymarket’s high temperature market for Miami was missing the winning bucket, and the ones around it.<br>Then, the May 17th market for Miami was “archived” — which is not what happens to markets that are resolved normally — along with the money that people had bet on it. Other markets followed (or preceded; its hard to find a clear timeline).<br>There was no official response from Polymarket about what had happened, and speculation was confined to the comments, X, and Reddit.<br>Someone speculated that it was an exploit, pointing to the Mexico City trader’s wallet (though that person might have just noticed something was weird, or gotten lucky):<br>🚨 Bad resolution on Polymarket

Miami May 17 Highest Temp (86-87°F) resolved as No ❌

But official high is 87°F on Wunderground KMIA. Resolved way too early.@Polymarket @UMAProtocol can we get a review?#Polymarket #ResolutionIssuehttps://t.co/Ml6wUxzieC<br>— 𝔻𝕖𝕗𝕝𝕒𝕩 💥 (@Deflax_) May 17, 2026

Rumors surfaced of an Oracle bug:<br>POLYMARKET DIGEST — 18 MAY 2026

⚠️ Bugs & Issues<br>Major weather market oracle failure caused wrong temperature brackets to be resolved across multiple cities (Miami, Mexico City, Seoul, Hong Kong). Mass archiving of weather markets led to positions disappearing from portfolios.…<br>— Digest Polymarket & UMA Discord (@predictdigest) May 18, 2026

Eventually, all US and international temperature markets disappeared, not just for May 17th, retroactively, but also for May 18th to May 22nd.<br>High Temp Odds & Predictions 2026 | Polymarket<br>Explore live High Temp prediction markets as of May 18, 2026. Track real-time odds and trade on The World’s Largest Prediction Market™<br>Polymarket

The only acknowledgement from Polymarket so far seems to be this tweet from @kea1on:<br>There has been a misconfiguration on a very small subset of markets - mostly weather markets, and a couple of tweet markets. We have archived all the misconfigured ones and are going to issue refunds for these markets.<br>— keaton (@kea1on) May 18, 2026

The Polymarket status page shows no notices for May 16th, 17th, or 18th:<br>Polymarket - Status<br>Polymarket Status<br>Polymarket

I don’t know what's going on, but I thought it was strange enough that someone should collect what facts are available, and none of the big news outlets seem to be covering it yet.

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&copy; 2026<br>The Autodidacts

Published with Ghost & Laminim