Highest temperature in San Francisco on June 30?

Platform comparison

Market context

The real-world event hinges on the peak temperature recorded at San Francisco International Airport on 30 June 2026, measured in degrees Fahrenheit and sourced from Wunderground. This single data point determines the market resolution, with the settlement window closing at 12:00 UTC on that date. For a power-user building automated strategies, the approach involves programmatically querying the Wunderground API for the daily maximum at KSFO, parsing the Fahrenheit value, and comparing it against the predefined temperature ranges to trigger conditional orders or copy-trading signals.

Historically, June highs at KSFO typically range between 61°F and 80°F, with daily averages climbing from 68°F to 71°F as the month progresses [2]. However, the first half of summer 2026 has been notably cool, marking the coldest since 1965 with an average maximum of just 67.6°F through 15 July [6]. This anomaly explains the current crowd-implied probability of 0% YES for higher temperature ranges, as the prevailing trend suggests temperatures will likely remain within the lower bands rather than exceeding historical extremes.

Traders should monitor daily climatological reports from the National Weather Service and real-time METAR data for KSFO, which currently show a maximum of 73.9°F over the past six hours [4][9]. Key catalysts include shifts in Pacific marine layer intensity and wind patterns, as a fresh westerly breeze at 18 mph is currently moderating temperatures [1]. Any sudden breakdown in the marine layer or sustained high-pressure systems could act as the primary driver for a temperature spike, requiring close observation of forecast updates from AccuWeather for July trends [5].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in San Francisco on June 30? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Kalshi Fees, which mirrors the Polymarket order book at 0% fees.

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 Kalshi Fees. 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.

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.

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.