Highest temperature in Seattle on August 9?

Platform comparison

Market context

Seattle’s highest temperature on 9 August 2026 is now priced by the crowd as a near certainty in the **76–77°F** bucket, with the market showing **0% YES** on the lowest outcome and effectively no meaningful disagreement left in the book.[1] For a handicapper, that makes the listed favourite the default, while the only real “underdog” angle is whether the airport station touches a different band if the day runs a shade cooler or warmer than the forecast cluster implied by traders.[1]

That consensus fits Seattle’s August climatology: the city’s normal early-August highs are typically in the mid-70s to low-80s, and recent comparable observations have often finished close to the upper 70s rather than in extreme heat.[4][7] The main contrarian case is not a cold spell so much as a small miss versus the dominant band, because the market resolves off the Seattle-Tacoma International Airport Station daily observations table, not the more visible day-high summary, so even a one- or two-degree difference in the recorded peak can matter for the settlement bucket.[5]

The catalyst traders should watch is the final airport observation for the settlement day, since the relevant source is Weather Underground’s Daily Observations table for Seattle-Tacoma International Airport Station.[5] In practical terms, the value question is whether the market has already over-anchored to the most likely range, leaving little price room unless late-day warmth or marine influence nudges the maximum into an adjacent bucket; with the current line already at 100% on the favourite, any contrarian position depends on a material miss rather than a normal forecast swing.[1][3]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Seattle on August 9? 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

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.

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.

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 Who Will Win 2026 trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.