Highest temperature in Tokyo on August 4?

Platform comparison

Market context

Polymarket is pricing the Tokyo Haneda Airport temperature contract at **0% YES** today, so the market is implying that none of the listed Celsius bands is currently being paid for in size. Because the resolution is tied to the *highest* temperature recorded at Tokyo Haneda Airport Station on 4 August 2026, the key variable is the day’s peak, not the morning reading; the contract settles from Wunderground’s daily history page and the outcome will be determined by the final Celsius maximum there.

For context, Tokyo’s August climate is usually hot and humid, with typical daily highs clustered in the low 30s Celsius and average August highs around 31–33°C in many forecast guides.[1][7][14][16] Current forecast data for 4 August also points to a hot day, with one Tokyo hourly forecast showing 88°F at present and August daily highs around 85°F, while broader August forecasts for Tokyo range up to about 90°F.[2][1] That means the market should be read against a familiar summer heat profile rather than an exceptional outlier; on conditional-token markets, the spread across bands usually reflects how much extra heat traders think is left in the afternoon rather than the month’s average.

The main catalysts are mundane but important: cloud cover, rain bands, and any convective burst that caps the afternoon high, plus whether the airport station runs a degree or two cooler or warmer than central Tokyo. Japan’s weather service data already shows a very hot start to August in Tokyo, with 1–2 August highs in the mid-30s Celsius, so traders will be watching whether that heat persists into the settlement window.[8][10] On-chain, positions are held in USDC on Polygon through conditional tokens, so price changes can be driven by thin liquidity as weather updates come in, especially if the afternoon forecast shifts after the morning read.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Tokyo on August 4? 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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Kalshi UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

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.