Highest temperature in San Francisco on July 12?

Platform comparison

Market context

San Francisco International Airport is expected to record its highest July 12 temperature in degrees Fahrenheit, with the market currently pricing any outcome above the lowest range at zero probability. Historical data shows daily highs in mid-July typically hover around 70°F, rarely exceeding 79°F, while extreme heat waves have pushed airport readings to 87°F in recent years[1][2]. The current 0% implied probability for higher ranges appears misaligned with the region’s thermal ceiling, as all-time records for the airport include 87°F in 2013 and even 103°F in San Francisco proper during a 2000 event, suggesting the market may be underpricing moderate heat scenarios[2][3].

Traders should monitor the National Weather Service Bay Area forecasts and Wunderground’s daily KSFO history updates, as the settlement relies exclusively on the highest temperature recorded at that station on 12 July 2026[2][9]. A key catalyst is the potential for inland heat domes to push marine air temperatures higher than usual, a pattern seen during the 2021 Bay Area heat wave when the airport hit 87°F[2]. With the settlement window closing at 12:00:00Z on 12 July 2026, any divergence between sportsbook lines on temperature ranges and this prediction market’s zero probability could signal an arbitrage opportunity, particularly if forecast models begin indicating temperatures above 75°F[4].

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

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 Best Prediction Markets. 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'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.

Do I need to KYC for this market?

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

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.