Highest temperature in Tokyo on July 5?

Platform comparison

Market context

On 5 July 2026, the Tokyo Haneda Airport Station will record its peak daily temperature, a real-world event that determines the settlement of a weather prediction market. Historical data for Haneda in July shows daily highs typically ranging from 76°F to 91°F (24°C to 33°C), with overnight lows between 68°F and 78°F [3]. Recent years confirm Tokyo summers are consistently humid with temperatures often reaching the low 30s Celsius, accompanied by daily rain or cloud cover [6]. The current crowd-implied probability of 0% for the market’s specific outcome appears misaligned with Polymarket’s frontrunner, which assigns a 54% chance to 27°C and 44% to 26°C [1], suggesting a divergence in how platforms interpret implied probability versus decimal odds.

Traders should monitor the National Weather Service’s forecast for severe thunderstorm clusters, which could suppress peak temperatures, as noted in recent observations for 4 July [4]. Japan’s all-time heat record of 41.1°C, set in Kumagaya in 2018, underscores the region’s capacity for extreme heat, though Haneda’s coastal location usually moderates extremes [7]. Platform mechanics further complicate the picture: Polymarket operates with minimal KYC and fee structures based on liquidity, while Kalshi and Betfair enforce stricter identity verification and differ in fee models, affecting liquidity depth for niche weather events. Smarkets and Kalshi also vary in how they present decimal odds versus implied probabilities, leading to inconsistent pricing for the same temperature range. These structural differences mean the 0% probability on one book may reflect a platform-specific interpretation rather than a genuine market consensus on the weather outcome.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We read Highest temperature in Tokyo on July 5? 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

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.

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.

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.