Highest temperature in Tokyo on July 9?

Platform comparison

Market context

Tokyo’s Haneda Airport is set to record its official daily high temperature on 9 July 2026, with the market currently pricing a 29°C outcome at 0% YES despite traders on other platforms estimating a one-in-three chance. While Polymarket shows the 29°C band priced at 0.32 (implying 31.5% probability), Kalshi and Betfair typically express such views as decimal odds rather than implied probabilities, and their fee structures and KYC requirements diverge sharply from Polymarket’s permissionless model. This 0% crowd-implied probability on the current venue suggests either a liquidity gap or a stark disagreement with the consensus seen elsewhere, where total volume remains concentrated in the final trading window.

Historical data frames this low probability as questionable: July in Tokyo routinely sees highs between 27°C and 31°C, with Haneda’s July 2026 forecast projecting daily highs from 76°F to 91°F (24°C–33°C). Recent records show Japan hitting 41.2°C in Tamba city, underscoring the region’s capacity for extreme heat, while BBC Weather notes drizzle and a 27°C high on 7 July. Traders should monitor the Japan Meteorological Agency’s hourly updates and Wunderground’s real-time station data, as a sudden shift in cloud cover or wind direction could push the high above 29°C. The Met Office forecasts a 31°C maximum for Haneda in the coming week, reinforcing the risk that the 29°C band is too narrow to capture the true outcome.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We read Highest temperature in Tokyo on July 9? 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

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.

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. Robinhood Prediction Markets 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.

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.