Highest temperature in Istanbul on July 4?

Platform comparison

Market context

The underlying event is the peak daily temperature recorded at Istanbul Airport on 4 July 2026, measured in degrees Celsius by NOAA. Current crowd-implied probability for the 25°C range sits at 0%, a stark divergence from historical norms where Istanbul’s mean maximum on this date typically runs between 27°C and 29°C[2]. Long-term averages show daily highs in July rarely fall below 75°F (23.9°C) or exceed 90°F (32.2°C), with a steady increase of 3°F across the month[1]. Even as Turkey recently recorded its all-time high of 50.5°C in Silopi during a July heatwave, that extreme occurred in the far southeast, not the coastal capital[3][6]. The 0% line appears to misprice the contract unless an unprecedented cold anomaly is forecast, given that recent normals indicate a slight rise in daily highs and a significant increase in lows[4].

Traders should monitor the NOAA time-series feed for Istanbul Airport (site LTFM) as the primary settlement dependency, watching for the first published data point on 4 July 2026[2]. No immediate weather announcements are expected, but the broader context of Europe’s third-hottest July on record suggests heat pressure remains high across the region[6]. Analyst consensus aligns with the 27–29°C band, making the 25°C target an outlier unless a sudden marine influx or cloud cover disrupts the typical solar energy input, which remains constant at roughly 7.7 kWh throughout July[1]. The settlement window closes at 12:00 UTC on 4 July 2026, requiring real-time verification of the “Temp” column peak[2]. Any divergence between sportsbook lines and prediction-market odds likely stems from this misalignment with historical climatology rather than a genuine cold forecast.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Istanbul 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

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

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.

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