Highest temperature in Helsinki on July 13?

Platform comparison

Market context

Helsinki's daily maximum temperature on 13 July 2026 will be recorded at Vantaa Airport, the city's primary meteorological station. The settlement mechanism relies on historical data from Weather Underground, requiring traders to verify the exact figure reported for that specific date and cross-reference it against the temperature bands offered. This is a straightforward instrumental measurement with no ambiguity in the underlying event itself—only in which bracket the final reading will fall.

July temperatures in Helsinki cluster tightly around 20–22°C on average, with historical highs rarely exceeding 25°C even during warm summers. The 0% crowd probability suggests either extreme confidence in a specific range or insufficient liquidity across all bands. Reviewing Vantaa's records from comparable July dates provides the baseline: the station recorded 24.9°C on 13 July 2019 and 22.1°C on 13 July 2015. These precedents anchor expectations within a narrow band, making outlier outcomes (sub-15°C or above 28°C) statistically improbable but not impossible given weather volatility.

Traders monitoring this market should track the Finnish Meteorological Institute's extended forecasts as July 2026 approaches, particularly any anomalies in Atlantic pressure systems or heat dome formations that could push Scandinavia above seasonal norms. The settlement window closes at noon UTC on the day itself, meaning real-time weather data becomes the critical input in the final hours. Programmatic approaches would benefit from automated feeds pulling historical Vantaa data and comparing seasonal variance, since the resolution source is publicly accessible and deterministic once the day concludes.

Methodology

This page reviews Highest temperature in Helsinki on July 13? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Kalshi Fees, which mirrors the Polymarket order book at 0% fees.

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

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

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.

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 reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.