Highest temperature in San Francisco on August 5?

Platform comparison

Market context

San Francisco’s high on 5 August is the airport’s hottest reading for the day, not the citywide afternoon average, so the market turns on the exact peak reached at KSFO rather than a rounded forecast headline. For programmatic trading, the practical input is the daily history page at Wunderground, where the station’s maximum can be checked against the market’s temperature bands; the current crowd has clustered around the low-to-mid 70s, with 70–71°F and 72–73°F both near 49%, while the 0% implied YES suggests the shown contract is already priced as essentially out of the money for the relevant range. [1][3]

Historically, San Francisco August highs are usually moderate because the marine layer and onshore flow cap daytime warming, and airport readings often differ from inland neighbourhood temperatures. Recent climate summaries and daily forecasts for the city point to a typical August high around the upper 60s to low 70s, which is why traders often model this market as a narrow-band outcome rather than a wide tail event; the useful question is whether the day breaks slightly warmer than normal or stalls in the upper 60s. [2][6][14][17]

For a power-user workflow, the main catalysts are the observed morning cloud cover, coastal wind direction, and any late changes in the marine inversion, since those directly affect whether KSFO prints a value that spills into the next temperature bucket. If you are automating entries, the relevant dependency is not a schedule item or policy announcement but the live weather path into the settlement window, with the final state determined by the Wunderground station record rather than a forecast model. [1][3][10]

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 Kalshi Fees, which mirrors the Polymarket order book directly.

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

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.

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.