Highest temperature in San Francisco on June 30?

Platform comparison

Market context

San Francisco’s June 2026 weather has remained consistently cool, with daily highs forecast between 65°F and 67°F and overnight lows from 54°F to 57°F, reinforcing the crowd-implied 0% probability that the peak temperature on 30 June will reach the 72–73°F range[1]. This aligns with historical norms: the average high for June at San Francisco International Airport is 66°F, and the record high for 30 June stands at 99°F in 1985, but typical maxima rarely exceed 73°F[2]. In recent years, even the warmest June days have hovered near 72.7°F, making a sudden spike above 73°F highly improbable without a significant atmospheric shift[10].

Traders should monitor the National Weather Service’s daily climatological reports and Wunderground’s real-time updates for KSFO, as any deviation from the expected cloud cover or marine layer could signal a temperature anomaly[4]. CBS News’ First Alert forecast for 30 June noted persistent AM cloud cover continuing through the week, which typically suppresses daytime heating[8]. While no immediate heatwave is forecast for the Bay Area, the broader U.S. is experiencing record-breaking heat in the central and eastern regions, though this is unlikely to impact coastal California due to the stabilising Pacific influence[5]. Watch for any sudden changes in wind direction or humidity levels, as these are the primary catalysts that could alter the day’s thermal profile.

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 Prediction Today, 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

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 Prediction Today. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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 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.