Highest temperature in Seattle on August 5?

Platform comparison

Market context

Seattle-Tacoma International Airport’s highest temperature on 5 August is a late-summer weather print, and the market is currently pricing **0% YES**, which leaves the favourite firmly with the field rather than any one band. In handicap terms, that makes the quoted outcome an obvious underdog: the consensus is that none of the listed ranges are being given meaningful weight at present, so the value question is whether a warm, dry day can force a move out of that dead zone.

The historical frame is straightforward: Seattle’s August climate is usually warm rather than hot, with long-run daytime highs around the mid-20s °C, roughly the upper 70s °F, and recent August forecasts have clustered in the low 80s °F rather than extreme heat[7][10][1]. That profile matters because the airport often runs a little cooler than inland neighbourhoods, so a genuinely high daily maximum usually needs broad regional warmth rather than a brief local spike. On that basis, the contrarian angle is to look for a modestly elevated high rather than a true heatwave outcome.

The main catalysts are the actual synoptic setup in the Pacific North-West in the days leading into the window: any ridge of high pressure, offshore flow, or heat-advisory language across western Washington would lift the chances of a higher band, while cloud cover or marine influence would cap the upside. Recent alerting in the region shows that heat-advisory conditions can emerge quickly during August, so traders should watch official forecasts, local advisories and the airport-specific hourly trend rather than citywide averages[6][11].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Seattle on August 5? 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

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

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 Who Will Win 2026. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Who Will Win 2026 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.