Highest temperature in San Francisco on July 14?

Platform comparison

Market context

San Francisco’s July heat is a battle between coastal marine layers and inland heat domes, with the city’s microclimate usually capping midday peaks well below 80°F. The market currently prices a 78–79°F outcome at 93%, treating anything above 80°F as a near-impossible underdog at just 6%. This 0% implied probability for a YES outcome on exceeding 80°F aligns with historical patterns: over the past decade, the San Francisco International Airport Station has recorded only two days in July exceeding 80°F, both during extreme 2021 and 2022 heat domes that overwhelmed the usual Pacific fog buffer.

The key catalyst for traders is the development of a high-pressure ridge over the Great Basin, which can suppress marine flow and push temperatures into the 80s. Watch the National Weather Service’s 5-day forecast for KSFO, particularly any mention of “heat dome” or “marine layer breakdown,” as these signals have preceded the city’s rare 80+°F days. A recent analysis from the Bay Area News Group notes that July 2026’s early-week pressure patterns are unusually stable, reducing the likelihood of a sudden heat spike, though a late-week shift could still create value for contrarian bets on the 80–81°F range if the ridge strengthens unexpectedly.

Sources: 1

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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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.

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 Who Will Win 2026 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.