Highest temperature in San Francisco on July 13?

Platform comparison

Market context

The market resolves to the highest temperature recorded at San Francisco International Airport on 13 July 2026, with the 6% YES probability for a specific outcome reflecting a tight consensus against extreme heat. Programmatically, a trader would script a scraper to pull daily maxima from the Wunderground history endpoint for KSFO, comparing the live forecast against the settlement range to identify arbitrage opportunities before the 12:00Z cutoff.

Historical data frames this low probability as rational, given that SFO has experienced its coldest first half of summer since 1965, with average maximums through mid-July sitting at just 67.6°F [4]. The warm season typically sees daily highs between 69°F and 79°F, making a spike significantly above this band statistically anomalous for this coastal location [1][3]. While record highs exist in the broader Bay Area, such as 116°F in Healdsburg in 1972, the airport station itself rarely breaches 80°F in July [7].

Traders should monitor the National Weather Service climatological reports for any sudden shifts in the Pacific high-pressure system, which drives inland heat domes toward the coast [8]. The primary catalyst is the 72-hour forecast update from AccuWeather, which currently projects daily highs capped at 79°F for the period [1]. A conditional order strategy would involve entering short positions if the forecast exceeds 75°F, as the market’s 24% weighting on the 76–77°F range and 50% on 78–79°F suggests the crowd expects a mild day rather than a heatwave [2].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Kalshi Fees, which mirrors the Polymarket order book directly.

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 Kalshi Fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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