Highest temperature in Madrid on August 9?

Platform comparison

Market context

Madrid’s key risk is a late-summer high around the airport station, with the market resolving on the highest **Daily Observations** temperature at Adolfo Suárez Madrid-Barajas rather than any headline “Day High & Low” figure. That matters for platform comparison: Polymarket shows the event in **implied probability** terms, while Kalshi, Betfair and Smarkets typically surface **decimal prices/odds** that need converting back into a percentage, and the end result can look different once fees and spread are included. Polymarket’s own market page had the main outcome around **37°C** at or near certainty, while wider forecast sources for Madrid on 9 August pointed to highs in the mid-to-upper 30s, including 36°C from AEMET-linked reporting and 36–37°C from commercial forecast services.[9][10][3][2]

For historical context, Madrid in August commonly sits well below the city’s record highs, but the airport can still print a much hotter reading than the city centre. August climatology for Madrid is roughly low-30s Celsius on the warmest days, and the city’s documented extremes show that airport measurements can run higher than the more familiar central-station records, which is why this market’s exact station and source hierarchy matter.[13][14][15] A 0% YES crowd price therefore reads as a strong view against a threshold above the leading forecast band, not a statement that heat is absent.

The main catalyst is the actual sequence of observations on 9 August and the first published reading for 10 August, because the market rules say later corrections only count until the next day’s first datapoint appears.[9] Traders on Polymarket should watch the forecast drift into the afternoon, while on Betfair or Smarkets the same view would be expressed through decimal prices net of exchange commission and, depending on jurisdiction, KYC access can be broader or narrower than on crypto-native venues. Any late spike from southerly airflow, cloud breaks or local station effects would matter more here than a citywide headline forecast.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in Madrid on August 9? 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, 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.

Which platform has the deepest liquidity?

Polymarket — by a wide margin. Top markets reach $50-500M volume, Kalshi ~$200M cumulative, Betfair similar. Deeper liquidity means your trade moves the quote less.

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.

Are all these platforms regulated?

No. Kalshi is CFTC-regulated (US). Betfair and Smarkets are UK Gambling Commission licensed. Polymarket operates without explicit regulation — a different risk profile than a regulated sportsbook.