Highest temperature in San Francisco on August 10?

Platform comparison

Market context

The contract is about the **highest temperature at San Francisco International Airport on 10 August 2026**, using Weather Underground’s Daily Observations rather than any headline day-high figure. The current crowd-implied price of **0% YES** sits well below the weather context implied by live conditions and model-style forecasts, which have been pointing to a mild, summer-normal San Francisco day rather than an extreme heat event.[2][15][16] Polymarket’s own market page shows the contract concentrated in the **72–73°F** bracket, with no meaningful price assigned to the coldest bucket, so this looks more like a disagreement between venues and/or timing than a broad view that the airport would stay unusually cool.[9]

Historically, San Francisco August highs at the airport cluster in the low- to mid-70s, with the NOAA climate report listing a **73°F normal maximum** for 10 August and a **record maximum of 87°F** for that date.[5] AccuWeather’s local history similarly puts the day around the upper 60s, with a forecast high of **68°F** for 10 August and a last-year high of **67°F**.[8][16] Weather Underground’s own historical page for San Francisco shows a **67°F** historic average high and a recent observed high of **59°F** on the page snapshot provided, reinforcing that this market usually resolves in the low-to-mid range unless offshore warming or a strong downslope event pushes temperatures higher.[13]

Traders should watch the airport observations themselves, not downtown San Francisco readings, because the settlement source is specifically KSFO daily observations.[2][7] The key catalyst is the intra-day temperature trace on 10 August: if marine cloud cover holds through the afternoon, the winning bucket likely stays near the market’s existing consensus; if clearing arrives early and winds ease, the airport can briefly run warmer than the city core.[3][15] At the close of the window, the decisive number will be the highest value in Weather Underground’s Daily Observations table, so late-day updates and any source discrepancies matter more than the summary high displayed elsewhere.[1][2]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in San Francisco on August 10? 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

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 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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Kalshi vs Polymarket trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.