Highest temperature in Seattle on July 23?

Platform comparison

Market context

Polymarket is pricing the Seattle-Tacoma International Airport high for 23 July at **0% YES** across the listed temperature bands, so the contract is effectively treating the specific outcome as absent rather than merely unlikely. Because settlement uses the highest temperature recorded at KSEA in Fahrenheit on the day, the practical question for a USDC position on Polygon is whether the final airport maximum lands inside any available conditional token band once Wunderground’s daily history page is locked in.

That low price is easier to read against Seattle’s July climate than against any single forecast run. Typical July highs in Seattle are around **75°F** with cool nights, and the city’s summer pattern is usually warm but not extreme, which makes the upper temperature bins much harder to justify unless a brief heat surge reaches the airport directly[1]. NOAA’s KSEA time-series page also gives traders a live reference point for how the airport has been tracking before the settlement window closes, which matters because the market resolves on the *highest* reading rather than the afternoon peak alone[2].

The catalysts worth watching are the same ones that move any airport-temperature market: timing of marine push, offshore flow, and any short-lived heat advisories that change how high the thermometer can reach before the day ends. July in Seattle is often dry and fairly stable, with limited rain and long daylight, so the main risk is not precipitation but whether regional heat builds enough to lift KSEA above the recent seasonal norm[3]. Traders should also remember that Polymarket’s price is set by conditional token demand on-chain, so any late model shift or update to the Wunderground record can reprice the bands quickly rather than gradually.

Sources: 1 · 2 · 3 · 4

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

FAQ

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.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

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 Kalshi UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.