Highest temperature in Paris on August 19?

Platform comparison

Market context

Paris is set up for a modest late-summer high, with live forecasts clustering around the mid-20s Celsius and some outlets showing a slightly warmer upper range for the day. That leaves the market far below any heatwave-style outcome and makes the lower temperature bands the more plausible settlement zone.

The 0% crowd price looks consistent with the way this kind of event is usually read: the overnight and early-morning profile matters less than the recorded maximum by noon UTC, and the stated resolution source is the Daily Observations table at Paris–Le Bourget Airport. In comparable August cases, Paris often sits close to its seasonal norm rather than breaking sharply higher, so a programme that maps the observed daily maximum into the market’s Celsius bands would usually skew to the nearest mid-20s bracket unless a short-lived burst of sunshine or convection lifts the peak.

For a trader running this programmatically, the key inputs are the latest hourly forecast, any nowcast showing shower timing, and the station feed itself once the settlement window is active. Recent local forecasts point to cloud and showers on 19 August, with one source flagging a real turn towards unsettled weather and afternoon temperatures around 24–27°C, which limits upside unless timing shifts later and clearing occurs before noon UTC.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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.

UK Frequently Asked Questions

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 Polymarket Review UK. 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.

Is Polymarket legal in the UK?

Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.

Do I pay tax on prediction market profits in the UK?

UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.

How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.