Highest temperature in San Francisco on July 12?

Platform comparison

Market context

San Francisco International Airport will record its highest temperature on 12 July 2026, with the market resolving to the Fahrenheit range containing that peak. The crowd currently assigns 0% probability to any “YES” outcome, implying near-certainty that the temperature will fall outside the listed range, though the specific range is not stated in the query. Historical July highs at KSFO typically sit between 67°F and 79°F, with the warmest average day reaching 72.3°F [2][9]. In early July 2026, the airport recorded highs of 70°F on 2 July and 72.6°F as the historic average for that date, suggesting the 12 July peak will likely remain within the 68–74°F band unless an unusual heat event occurs [8].

Traders should monitor the National Weather Service’s daily climatological reports for KSFO, which publish confirmed highs each morning after 12:00 UTC, and watch for any heat advisory announcements from California’s Office of Emergency Services [6][7]. Wunderground, the designated resolution source, updates its KSFO history page shortly after midnight UTC, making it the definitive reference for settlement [1]. Platform mechanics diverge sharply here: Polymarket displays decimal odds (e.g., 1.00 for 0% implied probability) and charges up to 2% fees with minimal KYC, whereas Kalshi uses implied probabilities directly, imposes lower fees (~1%), and mandates full US KYC; Betfair and Smarkets operate in decimal odds with higher commission structures and broader international access, creating arbitrage inefficiencies when one book misprices the 0% crowd signal [1][10].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We read Highest temperature in San Francisco on July 12? 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

Settlement is the biggest difference between the four platforms: Polymarket on-chain in USDC (instant), Kalshi USD via CFTC (T+1), Betfair and Smarkets in local currency via bank withdrawal (T+1 to T+3). On-chain settlement clears in minutes — the fastest payout path of the four.

FAQ

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.

Which platform has the deepest liquidity?

Polymarket — by a wide margin. Top markets reach $50-500M volume, Kalshi ~$200M cumulative, Betfair similar. Deeper liquidity means your trade moves the quote less.

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.

What about Smarkets as an alternative?

Smarkets is a UK betting exchange with a lower default commission (2%) than Betfair. Liquidity on political markets is below Polymarket, comparable to Kalshi. Geo-blocked in many jurisdictions.

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.