Highest temperature in Tokyo on August 4?

Platform comparison

Market context

Tokyo Haneda Airport’s top reading on 4 August will be driven by a single hot day’s peak, not the overnight low or the monthly average. Early-August Tokyo typically sits in the low 30s Celsius at the daily maximum, with AccuWeather putting August highs around 86°F and its 4 August forecast at 85°F; JMA’s 2026 Tokyo-area data also shows a very warm start to the month, with Tokyo, Haneda and other city stations already posting highs in the mid-30s Celsius on 1–2 August.[1][9][12]

The current 0% yes implies the market is pricing in a lower temperature band than the weather climatology would normally suggest, so traders should watch whether the day stays within the more moderate forecast range or spikes late afternoon. That matters because the market settles on the highest observed temperature for the day at Haneda, and a brief heat surge can push the reading into the next bracket even if much of the day feels merely warm.[1][12][17]

For catalysts, the main inputs are the live local forecast, cloud cover, sea-breeze effects and any rain or thunder that caps the daytime high; Tokyo in August is also the heart of the humid season and can see rapid changes in the afternoon.[1][16][19] On the market side, the event is settled in USDC on-chain, so there is no FX translation risk, but positioning in BTC and ETH can still matter indirectly if broader crypto volatility changes liquidity or risk appetite across prediction markets; those effects are most relevant when funding is stretched or whale flow is concentrated into short-dated outcomes, rather than as a direct driver of the weather itself.

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.

Why USDC and not ETH or USDT?

USDC is the Polygon standard — audited reserves (Circle, monthly attestation), deepest order book, low gas costs. ETH volatility would distort probability quotes; USDT has thinner Polygon liquidity than USDC.

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.

Are crypto prediction markets taxable in the US?

In the US, prediction market gains are typically treated as ordinary income or short-term capital gains depending on holding period. Consult a tax professional for your specific situation — we cannot provide tax advice.