Highest temperature in San Francisco on August 5?

Platform comparison

Market context

The contract hinges on the highest temperature logged at San Francisco International Airport on 5 August 2026, with the crowd currently pricing the most likely result around the low-70s Fahrenheit rather than a materially hotter outcome. Polymarket shows **72–73°F** as the front-runner at **51%**, followed by **74–75°F** at **21%**, while Robinhood’s comparable climate market is centred at **71°F**, suggesting the broader retail and prediction-market tape is aligned on a mild summer day rather than a heat spike.[2][13]

That pricing fits the historical pattern for San Francisco in August, when the city is usually moderated by marine air and daily highs cluster in the 70s more often than not. AccuWeather’s August outlook shows a 70°F high and 57°F low for one late-August day in the city, and WeatherSpark’s monthly climate pages likewise frame August as a comparatively cool, stable month by California standards, which helps explain why the market assigns only a small tail to outcomes above 76°F.[1][15] The main point for traders is that a 0% headline probability can be misleading on venues where contract bands are wide: the meaningful comparison is whether the distribution is skewed towards 72–75°F or whether a late-day warm-up pushes the airport station into the upper band.

What could still move the contract is not a policy or event calendar, but the final local weather setup: sea-breeze strength, afternoon cloud cover, and any inland heat ridge that briefly overcomes coastal moderation. Recent local coverage pointed to a wider California heat-up, but specifically noted that San Francisco would likely remain in the 70s and 80s, which is consistent with the current market leaning and leaves limited room for consensus to diverge unless forecasts sharpen materially hotter in the final hours.[18]

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

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 Best Prediction Markets. 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.

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.

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.