Highest temperature in San Francisco on August 10?

Platform comparison

Market context

San Francisco International Airport’s highest temperature on 10 August will be pinned to Weather Underground’s **Daily Observations** table, so the market is really about the top hourly reading there rather than any summary figure. Early verification from nearby official and historical sources points to a fairly mild day by San Francisco standards: the National Weather Service’s climate report for SFO shows **71°F** as the previous day’s maximum and a normal August 10 maximum of **73°F**, while WeatherSpark’s latest KSFO report on 10 August had already shown **66°F** by mid-morning with mostly cloudy conditions[5][2]. That sits awkwardly against the current crowd-implied probability of **0% YES** for a contract that resolves into temperature bands, suggesting the market is either pricing a specific band very narrowly or lagging the likely outcome.

For historical context, San Francisco’s airport often tops out in the 60s and low 70s in August, with Weather Underground’s own history page and other archives showing recent highs around **59°F** to **71°F** and an August climatological normal near the low 70s[13][5][12]. The odds picture therefore looks very different from the underlying weather baseline: prediction-market pricing at 0% on one side and public weather history implying a central tendency around the middle bands, while no sportsbook-style line is visible in the supplied data to anchor a direct cross-market comparison. In practice, the relevant comparison is whether the market is treating a sub-70°F outcome as far more likely than the climatology would justify.

Traders should watch the airport’s late-morning and early-afternoon evolution, because SFO highs often arrive in a narrow window and can be shaped by marine layer burn-off, onshore wind, and cloud cover rather than large-scale heat. The National Weather Service’s local observation page updates the station conditions directly, and its 01:43 AM PDT report already showed **59°F** at San Francisco downtown, underscoring the cool overnight starting point[14]. If clouds persist or the marine layer holds, the day’s peak can stay trapped in the upper 60s; if clearing accelerates, the airport can still reach the low 70s, which is the band that both official normals and recent history make hardest to dismiss[5][8].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to PolyGram, which mirrors the Polymarket order book directly.

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

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'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.

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 PolyGram 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.