Highest temperature in Tokyo on June 30?

Platform comparison

Market context

The 0% crowd-implied probability for a high-temperature range in Tokyo on 30 June 2026 reflects a sudden shift in the last 24 hours: forecasts for Haneda have dropped to a modest 28°C high, well below the thresholds that would trigger a “YES” resolution, despite recent regional heatwaves. This contrasts sharply with historical precedents where June 30s have occasionally breached 35°C, such as in 2023 when Tokyo recorded its highest June temperature since 1875 at 36.4°C, and in 2024 when the city logged 10 consecutive days above 35°C, marking its hottest-ever June and July period[3][4].

Traders should monitor the Japan Meteorological Agency’s daily heatwave bulletins and the scheduled release of Wunderground’s 24-hour high for Haneda at 12:00 UTC, which will determine the market’s final resolution. Recent news from AA.com.tr confirms that record-breaking June heat is not unprecedented, but the current forecast for Haneda shows no immediate spike, with temperatures expected to remain near 28°C and precipitation at 30%, suggesting no catalyst for a sudden surge[3][10]. The key dependency is whether the agency issues a heatstroke warning for the Tokyo metropolis before the settlement window closes, as such announcements often correlate with temperature spikes above 35°C.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Tokyo on June 30? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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.

Do I need to KYC for this market?

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

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.