Highest temperature in Chicago on August 9?

Platform comparison

Market context

Chicago’s temperature on 9 August has effectively settled around a mild-to-warm summer outcome, with the dominant contract range sitting in the mid-80s Fahrenheit and the crowd still assigning almost no weight to any extreme-hot scenario. On Polymarket, the leading bucket is **84–85°F at 99.8%**, while every other listed range is at **<1%**; by contrast, the market description here says settlement will follow the **Daily Observations** table at Weather Underground for Chicago O’Hare, which can differ from the broader “Day High & Low” display and therefore matters for the exact resolution bucket.[1]

That probability picture is broadly consistent with seasonal norms rather than with the rare-heat cases that occasionally reshape Chicago summer pricing. The National Weather Service lists the Chicago-O’Hare normal maximum for 9 August at **83.3°F**, with a record maximum of **97°F**, while AccuWeather’s August calendar shows **87°F/71°F** for 9 August 2026, close enough to explain why the market is clustered in the mid-80s rather than leaning into a lower or much hotter band.[3][11][2] In other words, the current 0% YES pricing on any given contract variant appears to reflect a consensus that the likely outcome is already well pinned to the expected daily range, not a view that the event cannot resolve at all.[1]

For traders, the main catalysts are the actual hourly and daily observations from O’Hare, plus any late-day revision that Weather Underground accepts before the next date’s first datapoint is published, since the contract explicitly allows revisions only up to that point.[1] The practical watchlist is therefore the sequence of observed highs rather than forecast hype: if the afternoon peak lands cleanly in the 84–85°F band, cross-platform odds should converge further; if readings push one bucket higher or lower, the contract can reprice quickly even though the wider analyst and forecast-calendar consensus still points to a fairly ordinary August high.[1][2][11]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Chicago on August 9? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Best Prediction Markets. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Best Prediction Markets trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.