Highest temperature in San Francisco on June 30?

Platform comparison

Market context

The real-world event centres on the peak temperature recorded at San Francisco International Airport on 30 June 2026, with the market currently implying a 0% chance of any outcome above the lowest range. Historical data frames this probability starkly: June in San Francisco typically sees a highest daily average high of 70°F on 29 June, with recent 15-day data from mid-to-late June 2026 showing a peak of 72.6°F[2][5]. While the city’s average summer temperature has warmed by 2.1 degrees since 1970, the current 0% implied probability diverges significantly from Polymarket’s collective view, which assigns a 35% chance to the 68–69°F range and a 28% chance to 70–71°F[1]. This suggests a meaningful gap between the current contract’s pricing and the broader cross-platform consensus on likely temperature bands.

Traders should monitor the National Weather Service’s hourly observations for KSFO and any sudden shifts in marine layer coverage, which often cap daytime highs in the Bay Area[7]. The resolution relies on Wunderground’s daily maximum for all times on 30 June, making real-time station data critical[6]. Although no specific weather announcements are scheduled for the immediate period, the trend of warmer summers across most of the US, contrasted with California’s micro-variations, remains a key dependency[4]. Analysts watching this contract must note that the current 0% implied probability appears inconsistent with the 72.6°F peak recorded just days prior, indicating a potential mispricing relative to recent empirical evidence[5].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in San Francisco on June 30? 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

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 Best Prediction Markets UK 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.