Highest temperature in Tokyo on July 4?

Platform comparison

Market context

On 4 July 2026, the Tokyo Haneda Airport Station will record its daily peak temperature in degrees Celsius, a single snapshot of summer heat that determines the outcome of a prediction market where the crowd currently assigns zero probability to any outcome above the lowest range. This event hinges on real-world meteorological conditions rather than market sentiment, with the resolution sourced from Wunderground’s official daily high for that location.

Historical data frames this 0% probability as highly questionable: Tokyo’s July average temperature is 28.7°C with humidity at 77.6%, and the city routinely sees highs in the low 30s during this month [9]. Just weeks prior, Japan recorded its highest-ever temperature of 41.2°C in Tamba City, shattering previous records and confirming a warming trend that makes a 26°C peak in Tokyo plausible [8]. Nearby Polymarket data for 3 July shows the frontrunner at 26°C with 100% implied probability, suggesting the market may be mispricing the 4 July event [1].

Traders should monitor the Japan Meteorological Agency’s hourly forecasts and global model updates for overnight lows near 20–21°C, which often precede strong daytime highs [2]. Recent news from Reuters confirms Japan’s record-breaking heatwave is ongoing, with July 2025 hitting unprecedented levels that could persist into 2026 [8]. Platform comparisons reveal key divergences: Polymarket uses decimal odds and low fees with minimal KYC, while Kalshi and Betfair rely on implied probability, stricter identity checks, and higher fee structures, affecting liquidity and pricing efficiency on this specific weather contract.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We read Highest temperature in Tokyo on July 4? 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

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 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.