Highest temperature in Seattle on July 23?

Platform comparison

Market context

Polymarket is pricing this Seattle airport heat contract at **0% YES**, so the market is currently treating a July 23 reading above the relevant Fahrenheit band as effectively impossible. On Polymarket, that price reflects trades in USDC on Polygon against conditional tokens, so the quote is a live crowd assessment of the Seattle-Tacoma International Airport Station’s eventual maximum temperature rather than a view on the broader weather pattern.

For context, Seattle’s July climate is normally mild by US standards: typical highs are around **75°F** and lows around **57°F**, with daylight still long and rainfall usually light. That makes the upper tail of the distribution the key issue here, because this market resolves off the **highest** temperature recorded at SeaTac on the day, not the daily average, so even one brief warm spell in the afternoon can matter more than the morning trend. Comparable July conditions in Seattle usually leave plenty of room for a comfortable result, but the contract is sensitive to any short-lived spike that pushes above the expected seasonal range.[1]

The main catalysts for traders are the forecast updates closest to the date, especially any warm, dry spell developing over western Washington, plus the intraday high at SeaTac itself, which is the settlement source. The resolution data comes from Wunderground’s historical daily page for KSEA, so a trader would usually watch for late forecast revisions, heat advisories, and the timing of the day’s peak warmth rather than headline averages or city-wide readings.[2][3]

Sources: 1 · 2 · 3

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

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 Polymarket Scam?. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.