Highest temperature in Helsinki on July 4?

Platform comparison

Market context

On 4 July 2026, the Helsinki Vantaa Airport Station will record its peak temperature for the day, a single real-world datum that determines the resolution of this prediction market. The current crowd-implied probability for the "YES" outcome sits at 0%, suggesting the market believes the temperature will fall outside the specific range being offered, despite typical early-July highs in Helsinki averaging around 21°C. Historical data from the Climate Service indicates that July 2025 began cooler than usual but concluded with a record-breaking heatwave where temperatures exceeded 30°C in parts of Finland, demonstrating the region's capacity for extreme volatility. While average daily highs at the airport rarely drop below 61°F (16°C) or exceed 81°F (27°C), northerly flows can suppress peaks by 2–3°C, creating a scenario where cooler outcomes are statistically plausible but often undervalued by consensus traders who lean toward the mean.

Traders should monitor the immediate forecast schedules for northerly wind anomalies, which act as the primary catalyst for suppressing temperatures below the expected 19°C threshold. The AccuWeather forecast for July 2026 projects daily highs ranging from 65° to 74°F (18°C to 23°C), yet the consensus heavily favours the 19°C outcome, potentially leaving value spots on the contrarian side if cooler air masses persist. Recent reports from the Finnish Meteorological Institute confirm that while July often ends with sweltering conditions, the month's start can be exceptionally cool, a dependency that could invalidate the current 0% implied probability if the market has overcorrected for heatwave expectations. The value likely sits in betting against the consensus 19°C favourite if northerly flows materialise, as the market appears to have priced in a warmer scenario that ignores the historical variability of early July in the Baltic region.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Helsinki on July 4? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Who Will Win. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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 Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Who Will Win trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.