Highest temperature in Tokyo on July 4?

Platform comparison

Market context

The underlying event is the peak daily temperature recorded at Tokyo Haneda Airport on 4 July 2026, measured in degrees Celsius via Wunderground. Current crowd-implied probability for a 27°C outcome sits at 57%, while the 28°C and higher ranges are priced near zero, suggesting the market expects a moderate heatday rather than an extreme spike.

Historical patterns frame this probability: mid-to-late July in Tokyo routinely hits 36–40°C with 95%+ humidity, yet Haneda’s coastal location often buffers extremes compared to inland cities like Tamba, which recorded Japan’s all-time high of 41.2°C in late July 2025[8]. Recent Polymarket data shows July 3 peaked at 26°C with 100% certainty[2], indicating a slight cooling trend before the 4th, which aligns with the current 27°C frontrunner[1].

Traders should monitor the Japan Meteorological Agency’s heatwave advisories and real-time wunderground feeds for Haneda, as sudden shifts in cloud cover or sea breeze can alter peak temps within hours. Reuters reported Japan’s hottest July since 1898, with multiple cities exceeding 41°C, but coastal stations like Haneda typically stay 3–5°C cooler[10]. Programmatically, conditional orders triggered by wunderground’s 12:00 UTC reading would capture intraday volatility before the 12:00:00Z settlement window closes.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in Tokyo on July 4? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Kalshi Fees, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

FAQ

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Kalshi Fees trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.