Highest temperature in Tokyo on May 22?

Platform comparison

Active sub-markets

Market context

Tokyo’s 22 May high will be measured at Haneda Airport, and the settlement outcome depends on the day’s recorded maximum in Celsius once the Wunderground history page is finalised. With the market sitting at 0% YES, the pricing implies no expectation of an unusually hot late-May spike. That is consistent with the climatology: Tokyo’s May highs typically sit in the low to mid-20s Celsius, with WeatherSpark showing average daily highs rising from about 21°C to 24°C through the month and rarely exceeding 27°C, while travel guides commonly place May highs around 20–25°C.

For context, a 0% line usually signals that the market is effectively only assigning value to an outcome outside the normal seasonal range, not to an ordinary warm day. In Tokyo, late May can still produce short-lived warmth, but the statistical centre of gravity remains well below summer heat. That means any comparison with sportsbook-style weather pricing or analyst consensus should start from the same baseline: a high in the low-to-mid 20s is the most plausible outcome, and a top-end reading would need a notably warm synoptic setup. The risk is not that Tokyo stays cool, but that the day briefly touches the upper part of its usual May band.

Traders should watch the morning and early-afternoon forecast trend, especially if a ridge of high pressure builds over eastern Japan and suppresses cloud cover. The key dependency is the official Haneda Airport observation rather than citywide averages, so local sea-breeze effects matter. Japan Meteorological Agency updates and airport-area forecast revisions are the main catalysts; if temperatures are already tracking near the upper 20s Celsius before noon UTC, the market’s 0% YES assumption would look increasingly stale.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Tokyo on May 22? on the five venues with material liquidity for prediction markets. Live odds come from the Polymarket Polygon order book — the only source that ships real-time data under an open licence. For Kalshi, Betfair and Manifold we list platform attributes (fee, KYC, settlement, payment) instead of fabricated odds, because their APIs use non-comparable contract definitions.

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?

On PolyGram, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

PolyGram is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

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 it cost to trade on PolyGram?

Zero. PolyGram routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

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.