Highest temperature in Tokyo on August 12?

Platform comparison

Market context

Tokyo's highest temperature on 12 August 2026 will be measured at Haneda Airport Station and resolved against Weather Underground's Daily Observations table rather than its Day High & Low summary—a distinction that matters when platforms diverge on data hierarchy. The current 0% crowd probability suggests either extreme confidence in a specific temperature range or minimal trading activity; across Polymarket, Kalshi, and Betfair, such flat probabilities often reflect low liquidity rather than certainty, particularly for niche weather markets where KYC requirements and fee structures create fragmentation in trader participation.

Historical August temperatures at Haneda show a median high around 32–33°C, with extremes ranging from 29°C to 37°C over the past two decades. The 2010 heatwave pushed readings to 36°C; conversely, cooler summers have produced August highs near 30°C. This historical spread means any single-degree resolution band carries meaningful probability mass, yet the crowd's 0% reading suggests either the market's range structure has eliminated a previously favoured outcome or trading has stalled. Kalshi's decimal-odds format and Polymarket's implied probability display can obscure identical underlying positions differently, affecting how traders perceive consensus.

Traders should monitor Japan Meteorological Agency forecasts released in late July 2026, which typically refine seasonal patterns and Pacific high-pressure positioning. El Niño or La Niña conditions, tracked by NOAA, influence August heat intensity across East Asia; current climate indices will be available by spring 2026. Weather Underground's data collection methodology at Haneda—specifically sensor calibration and observation timing—remains the binding constraint, making platform-specific settlement histories on comparable Japanese weather markets a useful reference for understanding resolution edge cases.

Methodology

We read Highest temperature in Tokyo on August 12? 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 mid is the canonical probability; the side-by-side columns benchmark fees, KYC, settlement currency and deposit rails so you can choose the venue that fits your jurisdiction and trade size.

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

Polymarket vs Kalshi — which is better?

Depends on your location. Kalshi is CFTC-regulated, US-only with full KYC. Polymarket is global, on-chain, no KYC up to $1,500. Polymarket has ~10x higher liquidity but higher regulatory risk.

What does Polymarket cost vs Kalshi?

Polymarket: 0% fees, only Polygon network costs (~$0.01/trade). Kalshi: up to 7% per trade plus spread. For high-frequency traders, Polymarket is dramatically cheaper.

Is Betfair a Polymarket alternative?

Only partially. Betfair Exchange is UK-focused with a sports-betting emphasis; they have politics markets but with thinner liquidity than Polymarket. Settlement in GBP/EUR, 2-5% commission on winnings.

What about Smarkets as an alternative?

Smarkets is a UK betting exchange with a lower default commission (2%) than Betfair. Liquidity on political markets is below Polymarket, comparable to Kalshi. Geo-blocked in many jurisdictions.

Which platform supports Klarna/SOFORT?

Directly: none. Polymarket accepts only USDC on Polygon. Kalshi Alternative offers a fiat on-ramp via Klarna or SOFORT (DE/AT/CH) and converts internally to USDC for the Polymarket order book. T+1 processing.