Highest temperature in Tokyo on July 7?

Platform comparison

Market context

On 7 July 2026, the Tokyo Haneda Airport Station will record its peak daytime temperature, a single real-world data point that determines the outcome of a weather prediction market. The current crowd-implied probability of 0% YES suggests the market believes the temperature will not fall into the specific bin being traded, likely a lower range inconsistent with typical July highs. This stark divergence from platforms like Kalshi, which emphasise decimal odds and strict KYC, contrasts with Polymarket’s permissionless, fee-light model where implied probabilities can swing more dramatically based on thin liquidity.

Historical July data for Haneda shows daily highs consistently ranging between 28°C and 32°C, with recent adjacent markets on 5 and 6 July resolving at 26°C and near-zero probabilities respectively, framing the 0% current reading as potentially mispriced or targeting an outlier bin. Platforms like Betfair and Smarkets, which aggregate liquidity across global books, often smooth such discrepancies, whereas Polymarket’s isolated bins can create sharp probability cliffs. Traders should monitor the Met Office’s seven-day forecast for Tokyo Haneda, which currently projects a maximum of 30°C, and watch for any sudden shifts in regional humidity or cloud cover that could depress temperatures below the 27°C threshold implied by competing markets on Lines.com.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We read Highest temperature in Tokyo on July 7? 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 is accessible globally?

Polymarket is geo-blocked in the US/UK/EU. Kalshi is US-only. Betfair and Smarkets are UK-restricted. Kalshi Alternative has a different geo footprint and routes to Polymarket's order book at 0% fees.