Highest temperature in San Francisco on July 13?

Platform comparison

Market context

San Francisco’s July heat is typically muted by coastal marine influence, making extreme highs at the International Airport rare. The market asks whether tomorrow’s peak will breach a specific high threshold, with the crowd assigning only a 6% chance to the YES outcome. Historically, daily highs in July hover around 70°F, rarely exceeding 79°F, while the airport’s all-time record sits at 87°F, set during a 2013 Bay Area heatwave [1][2]. Even during that event, most days stayed well below triple digits, and the 13th of July has not produced record-breaking temps in recent decades, with the Bay Area’s highest ever recorded on that date being 116°F in Healdsburg, not San Francisco [3].

The key catalyst is the development of a Pacific heat dome or a strong inland pressure gradient that could push hot air toward the coast. Traders should monitor the National Weather Service’s 48-hour forecast for KSFO, particularly any mention of “marine layer breakdown” or “advection of hot air from the Central Valley.” A recent NBC Bay Area report noted that when such conditions align, airport temps can spike 15–20°F above normal, but these events are infrequent and usually short-lived [2]. With settlement ending at noon UTC on 13 July, the critical window is the early morning hours when the marine layer typically holds. The 6% implied probability suggests the market views an extreme outlier as unlikely, but if a heat dome forms overnight, the value may lie in a contrarian YES position, as the crowd often underestimates the speed of coastal temperature surges during such events.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in San Francisco on July 13? 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 Who Will Win, which mirrors the Polymarket order book at 0% fees.

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.

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 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 Who Will Win trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.