Highest temperature in Tokyo on July 5?

Platform comparison

Market context

On 5 July 2026, the Tokyo Haneda Airport Station will record its peak temperature in degrees Celsius, a real-world event that determines the outcome of a prediction market where the crowd currently assigns zero probability to any “YES” outcome. This settlement hinges on data from Wunderground, specifically the highest temperature logged at any time on that day, and will be resolved once the window closes at 12:00 UTC. The market’s binary structure mirrors the decimal odds format seen on Polymarket, whereas Kalshi and Betfair often express outcomes as implied probabilities, creating a divergence in how traders interpret risk across platforms. Fee structures also vary: Polymarket typically charges no trading fees but embeds spreads, while Kalshi applies a small commission per trade, and Betfair’s model relies on a take-rate from winnings.

Historically, July in Tokyo has been consistently hot, with average daily highs exceeding 79°F (26°C) and recent years showing temperatures soaring nearly 3°C above normal, as reported by WION Climate Tracker [1]. In 2025, Japan recorded its highest-ever temperature of 41.2°C in Tamba City, Hyogo Prefecture, underscoring the volatility of summer heat in the region [6]. At Haneda Airport, July 2026 forecasts indicate daily highs between 76°F and 91°F (24°C to 33°C), with overnight lows from 68°F to 78°F [2]. These comparable cases suggest that a zero probability for “YES” is likely mispriced, especially given the meteorological department’s warning that above-average temperatures are expected to persist into August [1].

Traders should monitor the Japan Meteorological Agency’s weekly forecasts and any announcements regarding heatwave advisories, as these can signal spikes in temperature. Recent news from Reuters highlights that extreme heat and record-low rainfall have become a recurring pattern, with the department warning of sustained high temperatures [1]. The market’s dependency on Wunderground data introduces a technical risk: if the platform experiences downtime or data gaps, resolution could be delayed. Additionally, KYC requirements differ across platforms—Polymarket allows more anonymous participation, while Kalshi and Betfair enforce stricter identity verification, affecting accessibility for international traders. These structural divergences shape how liquidity and probability are priced on each book.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We read Highest temperature in Tokyo on July 5? 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

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 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.

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.

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. Kalshi Alternative UK 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.