Highest temperature in San Francisco on July 13?

Platform comparison

Market context

San Francisco is set to face another cool mid-summer day tomorrow, with the highest temperature at the International Airport likely to stay well below the 80°F threshold that would trigger a YES outcome on this market. The crowd currently implies only a 7% chance of a YES result, positioning the cooler ranges as the clear favourite while treating any significant heat spike as a long underdog.

Historical patterns strongly support the consensus leaning toward lower temperatures, as SFO has recorded its coldest first half of summer since 1965, with average maximums through mid-July sitting at just 67.6°F [4]. July forecasts for 2026 predict daily highs ranging between 67°F and 79°F, making a breach of the upper thresholds required for a YES outcome statistically improbable [1]. While record highs in the Bay Area have reached 103°F at the airport in September 1971, mid-July typically lacks the atmospheric conditions to drive such extremes [6].

Traders should monitor the National Weather Service climatological report issued for July 13, which will confirm the official maximum once the day closes [7]. The primary catalyst remains the persistence of the marine layer, which has suppressed temperatures consistently this summer, limiting the potential for the heat domes that occasionally push inland values higher. With the market pricing in a 50% chance for the 78–79°F range and 49% for 73°F or below, the 7% YES probability appears to offer fair value given the prevailing cool trend [2].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in San Francisco on July 13? 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 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.