Highest temperature in Tokyo on July 31?

Platform comparison

Market context

Tokyo’s high on 31 July will be judged by the warmest reading at Haneda Airport, so the key question is whether the airport reaches a level that lands inside the market’s target band before the noon UTC cut-off. The crowd has the event at **0% YES**, which implies the prevailing expectation is for a routine summer high rather than an outlier hot day.

Recent history gives some frame: Tokyo’s July highs are usually around the low 30s Celsius, with Haneda itself reaching 31.1°C on 31 July 2025 and nearby central Tokyo hitting 33.4°C that day, according to Japan Meteorological Agency data. More broadly, Japan has just come through an extreme heat spell, including a national record 41.2°C in Tamba on 30 July 2025 and a string of over-40°C readings elsewhere, so traders should not treat the distribution as static even if Tokyo usually runs cooler than the national hotspots.[7][9][15]

For platform comparison, the same weather event is priced differently across books: **Polymarket** shows the market as implied probability, while **Kalshi**, **Betfair** and **Smarkets** typically present decimal-style pricing and embed different fees or commission, so the effective break-even can diverge even when the headline price looks similar. The main catalysts are the day’s live temperature path, any late-morning coastal sea-breeze effects, and whether Japan’s broader heat pattern spills east towards the capital; Tokyo forecasts and official observations will matter more than national headlines once the market approaches settlement, because Haneda’s single highest reading is the only number that counts.[4][7][9]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in Tokyo on July 31? 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.

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.

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 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.