Highest temperature in Helsinki on July 4?

Platform comparison

Market context

The highest temperature recorded at Helsinki-Vantaa Airport on 4 July 2026 is currently priced at 0% probability for hitting 19°C or above on Polymarket, reflecting the market’s view that such a threshold is virtually unattainable under the prevailing conditions. This on-chain contract, settled in USDC on the Polygon network using conditional tokens, captures trader sentiment that the day will remain cool, with the Finnish Meteorological Institute forecasting a daytime high of just 19°C and low model spread[2].

Historically, July is Helsinki’s warmest month, with average daytime highs near 21°C and overnight lows around 15°C, though the month typically includes six rainy days and only gentle to moderate breezes[3]. While a record-breaking heatwave recently ended July with temperatures exceeding 30°C in parts of Finland, that event occurred later in the month and does not directly apply to early July conditions[1]. The current 0% pricing aligns with the expectation that early July 2026 will not replicate those sweltering late-month peaks.

Traders should monitor the 72-hour forecast updates from the Finnish Meteorological Institute, which already indicate a 19°C high with tight model consensus[2]. Additionally, watch for any sudden shifts in regional wind patterns or precipitation schedules, as these can suppress daytime temperatures further. The settlement window closes at 12:00 UTC on 4 July 2026, and resolution will rely on Wunderground’s official daily high for Helsinki-Vantaa, available via their public history portal[2]. No recent news announcements have suggested an imminent heat spike, reinforcing the market’s cautious stance.

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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

FAQ

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.

Do I need to KYC for this market?

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

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.