Highest temperature in San Francisco on August 10?

Platform comparison

Market context

San Francisco’s afternoon peak on 10 August settled in the high-60s to low-70s Fahrenheit, so the crowd’s **0% YES** price looks like a heavy favourite on an outcome that is already close to the city’s August norm rather than an extreme heat play.[1][12][18] AccuWeather’s forecast and other local outlooks clustered around **68°F** with lows in the high 50s, which makes a modestly warm result the base case and explains why the market is likely anchored in the **68-69°F** or adjacent bins rather than anything materially hotter.[1][13][14] For handicappers, the consensus sits with the standard marine-layer San Francisco profile: cool start, some clearing, and only limited upside unless the sea breeze weakens more than expected.[3][18]

Historically, August in San Francisco usually tops out around **68°F** on average, and the city’s record heat is highly skewed by rare offshore-wind events, with the all-time August maximum far above normal.[11][18] That means the real question is not whether it gets hot by local standards, but whether the airport station prints a small overshoot above forecast or stays pinned near the climatological mean.[11][17] With the market already pricing the more likely temperature ranges and assigning no weight to a YES outcome, the only real value angle is a contrarian one: a trader betting on a slightly warmer-than-expected airport reading if clouds clear earlier or winds turn less onshore than models implied.[1][3][17]

The main catalysts are the final National Weather Service forecast updates and the day-of marine-layer behaviour, because San Francisco temperature outcomes can move a few degrees depending on cloud burn-off, wind direction, and coastal advection.[3][12][14] Weather Underground settlement is tied to the **Daily Observations** table at **San Francisco International Airport Station**, so the key dependency is not the city centre headline but the airport’s logged maximum during the window.[17] Recent local reporting has also shown that Bay Area temperature surprises tend to come from broader regional heat episodes, but the available forecast signal for 10 August was for a fairly ordinary summer day rather than a heat-event setup.[19][14]

Sources: 1 · 2 · 3 · 4 · 5

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