Highest temperature in San Francisco on July 12?

Platform comparison

Market context

San Francisco’s July 12 heat is the underlying event, with the market betting on whether the San Francisco International Airport Station will hit a temperature range that currently carries a 0% crowd-implied probability for the “YES” outcome. Historically, mid-July highs at KSFO average around 70°F, rarely dipping below 64°F or exceeding 79°F, though extreme heat waves have pushed records to 87°F at the airport in 2013 and even 106°F in downtown San Francisco in 2017 [1][2][3]. The 0% implied probability suggests the consensus expects no chance of the specific temperature range being triggered, yet contrarian value may exist if a rare coastal heat dome develops, as July 12, 2021, saw a record-low maximum of just 57°F, proving the date’s volatility [9].

Traders should monitor the National Weather Service Bay Area forecasts for any incoming marine layer breakdown or offshore flow announcements, which are the primary catalysts for temperature spikes in San Francisco. Recent heat wave coverage noted that 98°F was tied in the Bay Area during a 2013 event, with KSFO hitting 87°F, indicating that even modest atmospheric shifts can breach typical ranges [2]. The settlement relies on Wunderground’s daily KSFO record, so any official NWS heat advisories or real-time station anomalies before the 2026-07-12T12:00:00Z cutoff will be decisive [2][10].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in San Francisco on July 12? 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.

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.

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.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.