Highest temperature in San Francisco on August 10?

Platform comparison

Market context

San Francisco's August weather typically peaks in the afternoon, with historical highs in the low-to-mid 80s Fahrenheit during summer months. The National Weather Service records daily maxima at San Francisco International Airport, the official station for the city's climate data. August 10th falls within the warmest period of the Bay Area's year, though marine layer influence often moderates temperatures compared to inland regions. The 0% crowd probability suggests traders expect the market's temperature bands to exclude the actual high, or that settlement ambiguity is deterring participation.

Historical August temperatures at SFO rarely exceed 85°F, with the station's all-time August record standing at 103°F in 1917. More recent decades show August highs clustering between 75°F and 82°F, reflecting the Pacific's cooling effect on the peninsula. The market's reliance on Weather Underground's Daily Observations table rather than the Day High & Low summary introduces a technical resolution risk; discrepancies between these datasets have occasionally caused disputes on weather-dependent contracts across Polymarket, Kalshi, and Betfair. Traders should verify which temperature bands the market offers before entry, as narrow ranges can inflate basis risk.

Atmospheric patterns through early August 2026 will determine whether high-pressure systems push inland heat toward the coast or whether typical marine stratocumulus maintains cooler conditions. The National Weather Service's extended forecasts become reliable only 7–10 days before August 10th. Kalshi's weather markets typically feature tighter spreads than Polymarket's equivalent contracts, whilst Smarkets' decimal odds format can obscure implied probabilities for casual traders unfamiliar with conversion. Fee structures vary significantly across platforms, affecting break-even thresholds on narrow temperature bands.

Methodology

We read Highest temperature in San Francisco on August 10? from four platform perspectives: Polymarket (on-chain CLOB), Kalshi (CFTC-regulated exchange), Betfair Exchange (sports book exchange), Smarkets (peer-to-peer betting exchange). Polymarket's live mid is the canonical probability; the side-by-side columns benchmark fees, KYC, settlement currency and deposit rails so you can choose the venue that fits your jurisdiction and trade size.

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.