Highest temperature in San Francisco on July 13?

Platform comparison

Market context

San Francisco faces its peak summer heat window tomorrow, with the San Francisco International Airport Station set to record the day’s highest temperature in degrees Fahrenheit. The market currently assigns a 6% implied probability to the “YES” outcome, suggesting traders expect the temperature to stay within a specific, cooler range rather than spike into extreme heat. This low probability aligns with AccuWeather’s July 2026 forecast for the airport, which projects daily highs between 67°F and 79°F, with overnight lows hovering near 54–59°F[1].

Historical patterns for mid-July at KSFO show average highs near 72.3°F, with the warmest days rarely exceeding 79°F[8]. On Polymarket, the frontrunner outcome is 78–79°F at 50% probability, while 76–77°F sits at 24%, indicating a divergence from the 6% YES implied probability on this specific binary contract[2]. Platforms like Kalshi and Betfair typically display decimal odds rather than implied probabilities, and their fee structures and KYC requirements differ significantly from Polymarket’s permissionless model, affecting liquidity and price efficiency on weather events.

Traders should monitor the National Weather Service’s daily climatological report issued by SFO, which will confirm the official high once the settlement window closes at 12:00 UTC on 13 July[6]. Wunderground serves as the definitive resolution source, and any discrepancy between its data and NWS reports could trigger disputes. Recent forecasts suggest no extreme heat advisories are in place for the Bay Area, reducing the likelihood of temperatures breaching the 80°F threshold that would flip the market[1].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in San Francisco on July 13? specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. The live probability is the Polymarket mid; the comparison columns summarise each venue's fee structure, KYC, settlement currency and payment rails. Every CTA routes to Robinhood Prediction Markets, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Polymarket settles via UMA Optimistic Oracle on Polygon. A proposer posts the outcome with a bond, the two-hour window runs, then the smart contract pays USDC.

Kalshi settles USD through the CFTC-regulated clearinghouse — the cleanest variant, with heavier KYC. Betfair Exchange settles in account currency (GBP/EUR), net of 2-5% commission. Smarkets follows the same model as Betfair with a lower default 2% commission.

FAQ

Polymarket vs Kalshi — which is better?

Depends on your location. Kalshi is CFTC-regulated, US-only with full KYC. Polymarket is global, on-chain, no KYC up to $1,500. Polymarket has ~10x higher liquidity but higher regulatory risk.

What does Polymarket cost vs Kalshi?

Polymarket: 0% fees, only Polygon network costs (~$0.01/trade). Kalshi: up to 7% per trade plus spread. For high-frequency traders, Polymarket is dramatically cheaper.

Is Betfair a Polymarket alternative?

Only partially. Betfair Exchange is UK-focused with a sports-betting emphasis; they have politics markets but with thinner liquidity than Polymarket. Settlement in GBP/EUR, 2-5% commission on winnings.

Which platform is accessible globally?

Polymarket is geo-blocked in the US/UK/EU. Kalshi is US-only. Betfair and Smarkets are UK-restricted. Robinhood Prediction Markets has a different geo footprint and routes to Polymarket's order book at 0% fees.

Which platform supports Klarna/SOFORT?

Directly: none. Polymarket accepts only USDC on Polygon. Robinhood Prediction Markets offers a fiat on-ramp via Klarna or SOFORT (DE/AT/CH) and converts internally to USDC for the Polymarket order book. T+1 processing.