Highest temperature in Madrid on June 29?

Platform comparison

Market context

On 29 June 2026, the Adolfo Suárez Madrid-Barajas Airport will record its peak temperature for the day, a single real-world datum that determines the outcome of this prediction market. Long-term averages place Madrid’s June daytime maximum at 28°C, with ten hours of daily sunshine and low humidity, though recent extremes have pushed temperatures significantly higher [1][4]. Just last week, Spain shattered two June records, with average daily temperatures reaching 28.17°C and surpassing the 2025 peak of 28.01°C, signalling that the current 0% implied probability for a high-temperature range may be overly conservative given the active heatwave [4].

Traders should monitor the National Meteorological Agency’s daily bulletins and Wunderground’s live hourly feed for the airport station, as these are the definitive resolution sources [1]. The divergence between platforms is stark here: Polymarket users see decimal odds reflecting a 33°C outcome with £31.7K volume, while Kalshi and Betfair traders rely on implied probabilities that currently dismiss the high range entirely, despite the fee structures and KYC requirements differing markedly across these books [2]. With the settlement window closing at 12:00 UTC on 29 June, the key dependency is whether the ongoing heatwave sustains its intensity through the afternoon, a factor that recent climate monitors suggest could push maxima toward 38°C, as seen on 22 June this year [7].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in Madrid on June 29? specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. The live probability is the Polymarket mid; the comparison columns summarise each venue's fee structure, KYC, settlement currency and payment rails. Every CTA routes to Kalshi Alternative UK, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Settlement is the biggest difference between the four platforms: Polymarket on-chain in USDC (instant), Kalshi USD via CFTC (T+1), Betfair and Smarkets in local currency via bank withdrawal (T+1 to T+3). On-chain settlement clears in minutes — the fastest payout path of the four.

FAQ

Polymarket vs Kalshi — which is better?

Depends on your location. Kalshi is CFTC-regulated, US-only with full KYC. Polymarket is global, on-chain, no KYC up to $1,500. Polymarket has ~10x higher liquidity but higher regulatory risk.

What does Polymarket cost vs Kalshi?

Polymarket: 0% fees, only Polygon network costs (~$0.01/trade). Kalshi: up to 7% per trade plus spread. For high-frequency traders, Polymarket is dramatically cheaper.

Is Betfair a Polymarket alternative?

Only partially. Betfair Exchange is UK-focused with a sports-betting emphasis; they have politics markets but with thinner liquidity than Polymarket. Settlement in GBP/EUR, 2-5% commission on winnings.

What about Smarkets as an alternative?

Smarkets is a UK betting exchange with a lower default commission (2%) than Betfair. Liquidity on political markets is below Polymarket, comparable to Kalshi. Geo-blocked in many jurisdictions.

Which platform is accessible globally?

Polymarket is geo-blocked in the US/UK/EU. Kalshi is US-only. Betfair and Smarkets are UK-restricted. Kalshi Alternative UK has a different geo footprint and routes to Polymarket's order book at 0% fees.