Highest temperature in Seattle on August 4?

Platform comparison

Market context

Seattle-Tacoma International Airport’s highest temperature on 4 August 2026 was the settlement driver, and the live market is already pricing a distinctly warm day rather than an extreme heat event. Polymarket’s leading band was **84–85°F at 50%**, with **82–83°F at 25%** and **86–87°F at 21%**, while Robinhood’s contract sat broadly in the same zone, with the price levels implying about **76¢ for >83°F, 49¢ for >84°F and 28¢ for >85°F**. That is consistent with the current crowd view: not a 90s-style outlier, but a mid-80s peak with some upside risk. [2][4]

Historically, Seattle’s August highs are usually much lower than this, so the market is effectively trading a warm-tail outcome rather than a seasonal norm. AccuWeather’s August forecast page showed Seattle around **81°F/62°F** for 4 August, while other forecast aggregators ranged around the low 80s, which helps explain why the market has clustered around 82–87°F rather than the cooler seasonal average. In cross-platform terms, the prediction market was more specific than the forecast sites: traders were not simply asking whether it would be hot, but whether the airport reading would land in a tight 2-degree bucket that depends on the day’s actual peak and timing. [1][5][6][9]

The main catalysts for traders were the same ones that move daily-temperature contracts elsewhere: the strength of the ridge, any marine push off Puget Sound, and whether cloud cover or late-day cooling clipped the airport’s maximum before the first next-day datapoint was published. Wunderground’s resolution rule means revisions can matter only until the first data point for 5 August appears, so late adjustments to the official airport history can still alter settlement if they arrive in time. Recent forecast commentary from Polymarket itself pointed to an upper-level ridge and warmer, sunnier conditions across western Washington, which would favour the upper-80s band if realised more strongly than expected. [2][8]

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, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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 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.

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.