Highest temperature in Tokyo on July 6?

Platform comparison

Market context

On 6 July 2026, the Tokyo Haneda Airport Station will record its daily peak temperature, a real-world metric that determines the outcome of a prediction market currently showing a 0% implied probability for any non-zero outcome on one platform. This stark divergence highlights how Polymarket, Kalshi, and Betfair interpret identical weather data differently: Polymarket assigns a 47% chance to 26°C and 44% to 25°C, while the other platform’s zero probability suggests either a structural error or a distinct definition of the settlement event. Traders comparing these books must note that Polymarket displays decimal odds reflecting crowd-sourced probabilities without mandatory KYC, whereas Kalshi requires identity verification and offers implied probabilities rather than raw odds, often leading to fee structures that penalise high-frequency arbitrage on volatile weather lines.

Historical July data for Haneda shows daily highs consistently ranging between 24°C and 31°C, with recent years recording averages 2.16°C above the 30-year norm due to intensifying heatwaves that have caused over 120 heatstroke deaths in Tokyo during July alone[8]. This warming trend frames the current 0% probability as highly anomalous, given that even the lowest July forecasts predict overnight lows of 21°C and daytime peaks of 26°C[4][5]. The catalysts to watch include the Met Office’s updated forecast for Mon 6 Jul, which explicitly lists a maximum daytime temperature of 26°C, and Wunderground’s real-time hourly logs that will serve as the official resolution source[5]. Traders should monitor for any sudden shifts in cloud cover or humidity, as these dependencies directly influence peak temperatures, while also verifying whether the settlement window’s 12:00 UTC cutoff excludes afternoon spikes that typically occur later in the day.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in Tokyo on July 6? 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 UK, 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.

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.

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 UK has a different geo footprint and routes to Polymarket's order book at 0% fees.

Are all these platforms regulated?

No. Kalshi is CFTC-regulated (US). Betfair and Smarkets are UK Gambling Commission licensed. Polymarket operates without explicit regulation — a different risk profile than a regulated sportsbook.