Highest temperature in San Francisco on June 30?

Platform comparison

Market context

The real-world event centres on the highest temperature recorded at San Francisco International Airport on 30 June 2026, with the market currently assigning zero probability to any outcome above the lowest range. Historical data for late June shows typical highs between 62°F and 70°F, with the average June high near 67°F[6]. Recent observations confirm this pattern: today’s maximum reached 74°F, while the six-hour peak was 73.9°F[3][5]. A similar Polymarket event on 16 June 2026 settled at 70–71°F with 100% implied probability, suggesting the market treats 70°F as the baseline upper bound for clear-sky days[1].

Traders should monitor the National Weather Service’s daily climatological report, which will confirm the official maximum temperature for the day[3]. Dependencies include wind speed and humidity, as a fresh westerly breeze and 67% humidity today helped moderate temperatures despite sunny intervals[2]. Unlike Kalshi’s decimal odds format, Polymarket uses implied probability percentages, while Betfair and Smarkets operate on a spread-betting model with different fee structures and KYC thresholds. These divergences mean the same 0% implied probability on Polymarket may reflect a near-zero decimal price on Kalshi but a different risk profile on Betfair, where liquidity and maker-taker fees alter the effective cost of a zero-probability bet.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in San Francisco on June 30? 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 Kalshi Alternative, 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.

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 is accessible globally?

Polymarket is geo-blocked in the US/UK/EU. Kalshi is US-only. Betfair and Smarkets are UK-restricted. Kalshi Alternative 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. Kalshi Alternative 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.