Highest temperature in Amsterdam on July 21?

Platform comparison

Market context

At Amsterdam Airport Schiphol, the market is effectively pricing a **cool day**: the crowd-implied probability is **0% YES**, which makes the favourite the lower temperature bands rather than any hotter outcome. That sits cleanly with the current consensus on the event page, which shows **22°C at 100.0%** for the July 21 settlement, leaving no apparent value in a hotter-print contrarian unless a late-data error or unusual spike appears.[1]

For context, mid-July in Amsterdam is usually not a one-directional heat story; the airport station often settles in the low- to mid-20s rather than in extreme ranges, so a 22°C outcome is a plausible centre-of-mass rather than a long shot.[2] In handicap terms, the market looks like a heavy favourite where the bookmaker-style price has already absorbed the expected climate baseline, so any value is more likely to sit in adjacent bins than in a big upside shock.

The main catalyst is simply the official daily maximum at Schiphol as recorded on Wunderground, since that is the settlement source, and the relevant watchpoint is the intraday high before the 12:00 UTC close of the settlement window.[1] Traders should track whether the airport briefly benefits from sunshine, wind direction, or a passing shower line, because those can shift the day’s maximum by a couple of degrees even when the broader regional pattern is stable; absent a major synoptic change, the consensus around the low-20s remains the central reference point.[2]

Sources: 1 · 2

Methodology

We track Highest temperature in Amsterdam on July 21? 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

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

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 Who Will Win 2026 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.