Highest temperature in Tokyo on July 23?

Platform comparison

Market context

Tokyo’s **23 July** peak temperature at Haneda will be set by the day’s highest reading at the airport station, and the current crowd view on Polymarket puts **35°C** at **97%**, with **36°C** at **2%**.[1] In plain terms, the market is pricing a very warm but fairly ordinary Tokyo summer day rather than a breakout heat event. July in Tokyo typically averages around **25–33°C**, with humidity often making it feel much hotter, so the centre of mass is still clustered around the mid-30s rather than the upper 30s.[2]

For comparison platforms, the same weather outcome is usually expressed differently: Polymarket shows **implied probability** directly, while Kalshi-style contracts are more often read through **decimal-like prices** that map to probabilities only after fees and spreads. That matters here because a 97% Polymarket price can look more absolute than a bookmaker quote, yet the economics differ once trading costs, maker-taker fees, or wide bid-ask spreads are included. Betfair and Smarkets also tend to expose market prices as odds rather than a single headline probability, and access can vary more sharply by jurisdiction because KYC and product availability are not identical across venues.

The main catalysts are mundane but decisive: the Tokyo heat forecast, cloud cover, sea-breeze timing, and whether any late-day thunderstorm or rain band suppresses the high before the settlement window closes at noon UTC. For a Haneda-specific contract, an airport-observed maximum can diverge from city forecasts, so traders should watch airport weather updates rather than only central Tokyo headlines. With the market already heavily concentrated at 35°C, the key question is whether forecast revisions push the day into 36°C territory or confirm that the airport peaks just below that band.

Sources: 1 · 2 · 3

Methodology

We read Highest temperature in Tokyo on July 23? 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

Settlement is the biggest difference between the four platforms: Polymarket on-chain in USDC (instant), Kalshi USD via CFTC (T+1), Betfair and Smarkets in local currency via bank withdrawal (T+1 to T+3). On-chain settlement clears in minutes — the fastest payout path of the four.

FAQ

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.

Which platform has the deepest liquidity?

Polymarket — by a wide margin. Top markets reach $50-500M volume, Kalshi ~$200M cumulative, Betfair similar. Deeper liquidity means your trade moves the quote less.

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. Robinhood Prediction Markets 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.