Highest temperature in Helsinki on July 13?

Platform comparison

Market context

On 13 July 2026, the highest temperature recorded at Helsinki Vantaa Airport will fall into one of several defined ranges. A YES share in this market represents a bet that the temperature will land in a specific bracket—say, 25–26 °C—whilst a NO share bets it will fall elsewhere. The settlement source is Wunderground's historical weather data for that station, which records hourly observations throughout the day. The market closes at midday on 13 July, meaning traders are predicting a full day's peak temperature based on seasonal patterns and any forecasted weather systems.

Helsinki's July temperatures typically peak between 20 and 24 °C, with extremes rarely exceeding 28 °C even during warm summers. The current 0% implied probability on the highest range suggests traders expect a cooler-than-average day or are concentrated on lower brackets. Historical records show that anomalously hot July days in Helsinki occur roughly once per decade; the station recorded 29.9 °C in July 2010 and 28.5 °C in July 2019. These outliers remain rare enough that most traders assign negligible odds to extreme-heat scenarios.

The key variable is the position of high-pressure systems across northern Europe in early July 2026. Traders should monitor European meteorological forecasts from mid-June onwards, particularly the North Atlantic Oscillation index and any heat-dome formations over Scandinavia. Wunderground itself publishes extended forecasts that update weekly; comparing those projections against historical analogues from similar pressure patterns will help calibrate expectations for the settlement day.

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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 Prediction Market UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

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.

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 Prediction Market UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.