Highest temperature in San Francisco on July 13?

Platform comparison

Market context

San Francisco International Airport is expected to record its peak temperature for 13 July 2026, with the market currently pricing a YES outcome at just 6% for the highest range. On Polymarket, traders are locking USDC on the Polygon network using conditional tokens, where the frontrunner outcome is 78–79°F at 50% probability, while 73°F or below holds 49% [2]. This tight split suggests the crowd views extreme heat as unlikely, aligning with the current forecast of daily highs between 67° and 79° for July 2026 at KSFO [1].

Historical context reinforces the low probability of record-breaking heat. SFO Airport has experienced its coldest first half of summer since 1965, with average maximums through mid-July sitting at just 67.6°F [4]. While all-time records exist, such as 103°F in September 1971, July 13 specifically has not seen temperatures exceeding 80°F in recent decades at the airport, making a spike into the 80s or higher an outlier event [7]. The climate normals show a typical maximum of 73°F, with the record high of 88°F set in 1983, further framing the 6% YES price as a rational bet against a heat anomaly [8].

Traders should monitor the National Weather Service’s daily climatological reports and real-time updates from Wunderground, the official resolution source, as the settlement window closes at 12:00 UTC on 13 July [2][10]. No specific weather announcements are scheduled for tomorrow, but sudden shifts in marine layer coverage or wind patterns could alter the peak temperature. The market’s reliance on KSFO data means local microclimates in the Bay Area, such as the 81°F record set recently at Salinas Airport, will not influence settlement, keeping the focus strictly on the airport station [5].

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 PolyGram, which mirrors the Polymarket order book directly.

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

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.

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.

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.