Highest temperature in San Francisco on July 13?

Platform comparison

Market context

The market hinges on whether San Francisco International Airport records a peak temperature exceeding the upper bound of its typical July range on 13 July 2026. Current forecasts for the airport indicate daily highs between 67°F and 79°F for the month, with overnight lows rarely dipping below 54°F [1]. Historical data confirms the warm season runs from mid-June to late October, averaging daily highs above 69°F, yet extreme outliers remain rare [2]. While the airport has recorded 87°F during past Bay Area heatwaves, tying records set in 2013, such events are infrequent anomalies rather than seasonal norms [3]. The current 6% YES probability aligns with this scarcity, reflecting a scenario where a significant heat dome must override the region’s characteristic marine cooling.

A programmatic trader would monitor real-time dependencies from the National Weather Service and Wunderground, the designated resolution source, for deviations from the 79°F forecast ceiling [1][10]. Key catalysts include the issuance of excessive heat warnings by the NWS Bay Area, which historically precede record-breaking days like the 81°F spike at nearby Salinas Airport [5]. Automated bots should track the 5-day forecast trend; a sudden shift toward 85°F+ projections would invalidate the current low probability. Traders must also watch for the coldest summer patterns, such as the 67.6°F average max recorded through mid-July 2024, which suppresses heat potential [4]. Any announcement of a Pacific high-pressure ridge strengthening over the region would serve as the primary trigger for re-evaluating the 6% implied probability.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in San Francisco on July 13? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Polymarket Bot UK, which mirrors the Polymarket order book at 0% fees.

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 Polymarket Bot UK. 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.

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 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.