Highest temperature in Wellington on July 20?

Platform comparison

Market context

Wellington International Airport’s highest temperature on 20 July 2026 is the real-world event determining settlement, with the market currently pricing a 12°C outcome at 100% implied probability. This contrasts sharply with the 0% YES crowd-implied probability for any alternative range, suggesting near-total consensus among Polymarket traders that winter conditions will hold. On platforms like Kalshi or Betfair, such certainty would typically appear as decimal odds of 1.01 rather than a probability figure, while fee structures diverge significantly: Polymarket charges no maker fees but imposes gas costs, whereas Smarkets applies a flat commission on winnings and Kalshi enforces KYC for all US participants, limiting access compared to Polymarket’s broader global reach.

Historical July maxima at NZWN rarely exceed 14°C, with MetService records showing 12°C as a frequent winter peak in recent decades, reinforcing the market’s confidence [2]. A trader should monitor MetService’s daily bulletins and Wunderground’s real-time updates as the settlement window closes at 12:00 UTC on 20 July, since any unseasonal southerly lull or coastal fog shift could alter the maximum [2][3]. BBC Weather currently reports 15°C with strong south-south-westerly winds, but this is a snapshot, not the day’s maximum, and the official resolution relies solely on Wunderground’s recorded peak for NZWN [3].

Sources: 1 · 2 · 3

Methodology

This page compares Highest temperature in Wellington on July 20? 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 Robinhood Prediction Markets, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Polymarket settles via UMA Optimistic Oracle on Polygon. A proposer posts the outcome with a bond, the two-hour window runs, then the smart contract pays USDC.

Kalshi settles USD through the CFTC-regulated clearinghouse — the cleanest variant, with heavier KYC. Betfair Exchange settles in account currency (GBP/EUR), net of 2-5% commission. Smarkets follows the same model as Betfair with a lower default 2% commission.

FAQ

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.

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. Robinhood Prediction Markets has a different geo footprint and routes to Polymarket's order book at 0% fees.

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.

Which platform supports Klarna/SOFORT?

Directly: none. Polymarket accepts only USDC on Polygon. Robinhood Prediction Markets offers a fiat on-ramp via Klarna or SOFORT (DE/AT/CH) and converts internally to USDC for the Polymarket order book. T+1 processing.