Highest temperature in San Francisco on August 10?

Platform comparison

Market context

The underlying event is the **highest temperature measured at San Francisco International Airport on 10 August 2026**, and this market settles from Weather Underground’s **Daily Observations** table rather than the headline Day High & Low summary. In prediction markets, a **YES** share pays out if the specified outcome happens, while a **NO** share pays out if it does not; here, the contract is effectively asking traders to price which temperature band will contain that airport station’s top reading. The setup matters because a late-day update or an observation revision can change the final bin even after an apparently settled daily high.

Historical data suggest San Francisco in August usually peaks in the upper 60s to low 70s Fahrenheit, with the airport’s climatological normal around **73°F** for 10 August and recent daily highs commonly clustered near that range.[4][11] Recent history also points to modest warmth rather than extremes: Weather Underground and other weather history services show nearby August highs generally in the 60s and 70s, with the month’s recent peak around **79°F** earlier in August 2026.[1][8] That context helps explain why a 0% crowd price can arise if traders think a listed temperature band is effectively impossible, or if the market has not yet attracted active participation.

For traders, the main catalysts are the airport’s official observation cadence, any late afternoon temperature spike, and any post-publication correction in the station log before the first datapoint for 11 August appears. The National Weather Service’s airport climate report and station history are useful cross-checks for the daily maximum and timing, while Weather Underground remains the resolution source for this contract.[4][9] On 10 August, the observed midday readings already sat around **69–71°F** with scattered clouds, which suggests the key question was whether clearing, sunshine, or an offshore wind shift could push the final reading into a higher temperature band.[1]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in San Francisco on August 10? 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

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.

UK Frequently Asked Questions

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 Prediction Market UK. 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.

Is Polymarket legal in the UK?

Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.

Do I pay tax on prediction market profits in the UK?

UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.

How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.