Highest temperature in Seattle on August 4?

Platform comparison

Market context

Seattle-Tacoma International Airport’s maximum temperature on 4 August 2026 is the settlement variable, and the current market is pricing a very hot day despite the contract’s 0% crowd-implied YES shown on the prompt. Across venues, that sits awkwardly beside Polymarket’s own displayed split, which has the 80-81°F band at 100% and other outcomes near zero, while Robinhood’s Seattle daily temperature high market is trading above 83°F at 76¢, with higher thresholds still meaningfully bid at 49¢ for >84 and 28¢ for >85.[2][4]

Historically, Seattle’s August highs are usually in the upper 70s to around 80°F, with AccuWeather’s August forecast page showing 81°F for 4 August and 80°F for 5 August, which is consistent with a late-summer peak but not an extreme outlier.[1] That makes the contract sensitive to the airport-specific reading rather than the city average: a one- or two-degree difference can move the outcome between adjacent bands, especially when forecasts cluster close to the boundary. In that context, the market’s 0% YES looks more like a stale or mispriced line than a clean expression of weather risk, given that other venues are already implying an 80s-type high.[1][2][4]

Traders should watch the Seattle-Tacoma airport observation feed and any late-day revisions, because this contract resolves from the highest temperature recorded at KSEA for the full day, and the market rules allow revisions until the first datapoint for the following date is published.[2] The key catalyst is therefore not a policy announcement but the actual intraday temperature path, with afternoon sunshine, marine-layer break-up, and any unexpected coastal cooling or inland warmth shifts likely to determine whether the high lands in the low 80s or pushes further into the mid-80s.[1][2][4]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in Seattle on August 4? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Best Prediction Markets UK, which mirrors the Polymarket order book at 0% fees.

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.

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 UK 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.