Highest temperature in Tokyo on July 31?

Platform comparison

Market context

Tokyo’s afternoon peak on this contract is a straightforward weather print, but the payoff can still be shaped by local heat dynamics rather than the broader “Japan is hot” headline. For Tokyo in July, normal highs sit around 30°C, yet recent daily data show the city repeatedly reaching the mid-30s, with Tokyo-area stations posting 33–36°C late in the month in recent years.[11][4] The market resolves on the highest temperature recorded at Tokyo Haneda Airport Station on 31 July, so the relevant number is the day’s maximum at that station, not the citywide average or an evening cooling trend.[5][8]

The current 0% crowd-implied probability for the top YES range needs to be read against Japan’s recent heat regime. This month has already seen nationally exceptional readings, including 41.2°C in Tamba, Hyogo, and further 40°C-plus readings elsewhere, which underlines how extreme Japanese summer heat can become when high pressure builds inland.[9][14] Tokyo itself is usually lower than the national inland records, but Haneda sits in coastal south-eastern Tokyo, where sea breeze and marine air can cap extremes compared with the hotter western suburbs and inland prefectures.[8][12]

Traders should watch the late-morning to early-afternoon evolution in Tokyo, because the settlement window closes at 12:00 UTC, which is 21:00 local time, leaving the entire daytime heating cycle to determine the print.[5] The main catalysts are the local synoptic set-up, cloud cover, rainfall or thunderstorm development, and any shift in the strength of the Pacific high that can suppress or amplify temperatures into the mid-30s.[7][15] In crypto terms, this is a USDC-settled binary on a single meteorological observation, so macro BTC or ETH moves matter only insofar as they affect overall market appetite; the contract itself is driven by the weather tape rather than on-chain flows.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically this overview focuses on on-chain pricing: Polymarket's live mid comes from the Polygon conditional-token order book and settles automatically in USDC. The other three venues — Kalshi, Betfair, Manifold — sit alongside as off-chain reference points so you can see how the contract translates across regulatory and settlement regimes.

Resolution & payout

Settlement is on-chain via UMA Optimistic Oracle. A proposer posts the outcome with a bond, a two-hour dispute window opens, then the smart contract lifts winning conditional tokens to 1 USDC and sends payments to holders' wallets automatically. No withdrawal fees beyond Polygon gas.

Off-chain venues (Kalshi, Betfair, Smarkets) settle in local fiat through bank-side clearing — faster than SWIFT, slower than on-chain. Manifold pays no real cash.

FAQ

What are crypto prediction markets?

Crypto prediction markets are on-chain smart contracts where you buy YES or NO shares on a future crypto event (e.g. "BTC above $100k by year-end"). The market price between 0¢ and 100¢ is the implied probability.

What does a transaction cost on Polygon?

Polygon gas is typically under $0.01 per transaction. A full trade cycle (Approve + Order + Fill) totals around $0.03 — compared to $5-50 on Ethereum mainnet.

Can I use Bitcoin directly?

No, Polymarket operates exclusively in USDC on Polygon. You can bridge BTC to USDC via an exchange or bridge service and deposit on Polygon — typically 10-30 minutes processing time.

How does UMA secure the resolution?

The UMA Optimistic Oracle uses a bond system: a proposer posts a bond, a two-hour challenge window opens. On dispute the losing side forfeits the bond — financial incentive for honest resolution.

How volatile are crypto prediction markets?

Crypto markets react to spot prices — a 5% BTC move typically shifts a "BTC above X by date" market 10-20%. Polymarket crypto market liquidity is usually six-figure USD, sufficient for active trading.