Highest temperature in Tokyo on June 8?

Platform comparison

Active sub-markets

Market context

On 8 June 2026, Tokyo's highest temperature will be recorded at Haneda Airport Station and settled against Wunderground historical data. The 0% crowd probability suggests either extreme confidence in a specific temperature range or minimal liquidity across all outcome buckets. Kalshi's binary structure typically forces sharper probability calibration than multi-outcome markets on Polymarket, where fractionalised ranges can diffuse trading activity. Betfair's decimal odds format and commission-based fee model (versus Kalshi's flat spreads) may attract different trader profiles for weather events, particularly those comfortable with lay positions on unlikely temperature extremes.

Tokyo's June climate shows considerable year-to-year variance. Historical data from the Japan Meteorological Agency indicates June highs in central Tokyo range from 26°C to 32°C, with 2023 recording 31.5°C on 8 June specifically. The settlement window closes at noon UTC (21:00 JST), creating a timing mismatch with Haneda's full daily observation period—traders must account for whether the final reading captures the entire day's peak or only morning-to-midday temperatures. Smarkets' lower minimum stake thresholds may appeal to retail traders testing edge on this niche market, though Polymarket's higher liquidity pools typically reward tighter spreads for established weather categories.

Monitoring Japan Meteorological Agency forecasts from late May onwards will signal whether atmospheric patterns favour above or below-median June temperatures. El Niño or early monsoon activity could shift probabilities materially in the final fortnight before settlement.

Methodology

We read Highest temperature in Tokyo on June 8? from four platform perspectives: Polymarket (on-chain CLOB), Kalshi (CFTC-regulated exchange), Betfair Exchange (sports book exchange), Smarkets (peer-to-peer betting exchange). Polymarket's live quote comes directly from the Polygon order book; the other three are listed with their platform attributes — fees, KYC, settlement currency, payment options — because a 1:1 contract comparison without API access would be guesswork.

Resolution & payout

Polymarket settles via UMA Optimistic Oracle on Polygon. A proposer posts the outcome with a bond, the two-hour window runs, then the smart contract pays USDC.

Kalshi settles USD through the CFTC-regulated clearinghouse — the cleanest variant, with heavier KYC. Betfair Exchange settles in account currency (GBP/EUR), net of 2-5% commission. Smarkets follows the same model as Betfair with a lower default 2% commission.

FAQ

Where can I trade this market with the lowest fees?

On Kalshi Alternative UK, 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?

Kalshi Alternative UK 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.

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 it cost to trade on Kalshi Alternative UK?

Zero. Kalshi Alternative UK 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.