Highest temperature in Tokyo on August 2?

Platform comparison

Market context

Tokyo’s hottest reading at Haneda Airport on 2 August will be set by the day’s actual peak temperature, with settlement based on Wunderground’s history page for RJTT rather than a forecast or a city-wide average. The current crowd-implied probability of 0% for a YES outcome looks out of line with the weather context: Tokyo’s August climate is typically hot and humid, with average highs around 31°C and many summer days reaching the low 30s Celsius, while short-term hourly guidance for 2 August already points to a warm start and a midday rise into the upper 20s to around 30°C[2][7][9][12].

Historically, this kind of contract is better read as a “will it print one of the common summer bands?” question than a true tail-event bet. Tokyo and wider Kanto frequently produce highs in the 30°C-plus range in August, and Japan’s meteorological outlook for summer 2026 has been described as above normal nationwide, with heat persistence after the rainy season; that supports a materially higher probability than zero for ranges anchored around the low- to mid-30s Celsius[16]. By contrast, lower bands depend on cloud, rain, or a cooler marine flow, and those outcomes are possible but not the baseline in early August[2][8][10].

For traders comparing platforms, the key divergence is between the exchange-style price implied by the 0% YES figure and the broader weather consensus from seasonal forecasters and commercial weather services, which cluster Tokyo’s August highs near 31°C and show same-day temperatures already tracking warm[1][2][9][10]. The main catalysts are local cloud cover, any afternoon showers or thunderstorm activity, and whether sea breeze or precipitation suppresses Haneda’s daily maximum before the 12:00 UTC settlement cut-off, which is 21:00 in Tokyo; any late-day heating after that point would not matter for resolution.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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 Best Prediction Markets 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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Best Prediction Markets UK 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.