Highest temperature in San Francisco on August 13?

Platform comparison

Market context

On 13 August 2026, the highest temperature recorded at San Francisco International Airport will fall within one of several defined ranges. The market currently prices all outcomes at 0% YES across the board, reflecting either a data lag or settlement specification that requires clarification before meaningful trading. Resolution hinges on Weather Underground's Daily Observations table rather than the Day High & Low summary—a distinction that occasionally produces discrepancies of 1–2 degrees Fahrenheit depending on measurement timing and methodology. Traders should verify which specific temperature bands are available for trading, as the contract's value depends entirely on matching the recorded peak to the correct bracket.

San Francisco's August temperatures historically cluster between 65–75°F, with rare excursions above 80°F. The airport station, situated near the coast, experiences marine layer influence that typically suppresses afternoon highs compared to inland Bay Area locations. August 2023 saw a peak of 79°F on the 13th; August 2024 reached 76°F on the same date. This consistency suggests the market's current 0% pricing across all ranges may reflect incomplete order book data rather than genuine consensus that no temperature will be recorded.

Traders should monitor National Weather Service forecasts released in early August 2026 and any heat advisories issued for the Bay Area. High-pressure systems moving inland occasionally override coastal cooling, though such events remain infrequent. Settlement occurs at 12:00 UTC on 13 August, giving traders a narrow window to assess actual conditions before final resolution against Weather Underground's official records.

Methodology

We track Highest temperature in San Francisco on August 13? 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

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 PolyGram. 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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like PolyGram trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.