Highest temperature in San Francisco on July 12?

Platform comparison

Market context

San Francisco’s highest temperature on 12 July 2026 will be measured in degrees Fahrenheit at the San Francisco International Airport Station, with the market resolving to the bracket containing that peak reading. On Polymarket today, the contract trades with a 0% implied probability for any outcome above the lowest bracket, reflecting extreme caution among traders despite July typically being the city’s warmest month. The settlement relies on Wunderground’s daily high for KSFO, locking in USDC payouts on Polygon once the conditional tokens resolve after the 2026-07-12T12:00:00Z cutoff.

Historical data frames this near-zero pricing as an outlier rather than a consensus. July 9, 2026, saw a confirmed high of 66–67°F at KSFO, while the 2026 July forecast projects daily highs between 67°F and 79°F, with overnight lows of 54–59°F[2]. Yet SFO Airport recorded its coldest first half of summer since 1965 through 15 July, averaging just 67.6°F, suggesting persistent marine influence that suppresses heat spikes[5]. Even during a recent Bay Area heat wave, KSFO hit 87°F—a record break from 85°F in 1973—indicating that extreme highs are possible but rare[7].

Traders should monitor the National Weather Service’s 7-day forecast for KSFO, which currently predicts a high of 77°F on 13 July following mostly cloudy conditions turning sunny[6]. The key catalyst is the timing of any inland heat surge or marine layer breakdown, as these directly impact KSFO’s peak temperature. Watch for updates from the NWS Bay Area on heat wave developments, as past records show rapid temperature shifts can occur within hours[7]. No official announcements are scheduled, but real-time dependencies include wind direction (WNW at 10 mph) and UV index (9.0, very high), which correlate with daytime heating intensity[8].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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 Kalshi 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.

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.