Highest temperature in San Francisco on June 30?

Platform comparison

Market context

The underlying real-world event is the highest temperature recorded at San Francisco International Airport on 30 June 2026, measured in degrees Fahrenheit. Current Polymarket pricing shows a 0% implied probability for the "YES" outcome, reflecting the market’s conviction that the temperature will fall outside the proposed range. This contract trades on Polygon using USDC, with conditional tokens determining settlement once the resolution window closes at 12:00 UTC on 30 June 2026.

Historical June data frames this near-zero probability. AccuWeather reports typical June highs between 62°F and 70°F, with an average high near 66°F[5]. Recent METAR data for KSFO shows a 6-hour maximum of 66.0°F and a daily high of 72.0°F on 29 June[4][7]. The BBC Weather forecast for today lists a high of 67°F[2]. These figures consistently sit well below extreme heat thresholds, supporting the market’s assessment that the temperature will not reach the upper range.

Traders should monitor the National Weather Service climatological report for KSFO, which details daily maximums and climate normals[3]. Any sudden shift in wind patterns or marine layer breakdown could elevate temperatures, though such events are rare in June. The resolution source is Wunderground’s official daily record for KSFO, so discrepancies between METAR and Wunderground data may affect settlement[6]. No major weather announcements are scheduled, but the marine layer’s stability remains the key dependency for temperature outcomes.

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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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 PolyGram. 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'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.

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.