Highest temperature in Wellington on July 31?

Platform comparison

Market context

Wellington’s highest temperature on 31 July will be measured at Wellington Intl Airport, and the market settles on the temperature band containing that day’s peak reading from Wunderground rather than on a rounded daily average. With the crowd pricing this at **0% YES**, the implied view is that a specific range is extremely unlikely to be hit, so on Polymarket the key figure to compare is the implied probability, while on Kalshi, Betfair or Smarkets traders will usually see decimal prices or exchange-style odds that can move more sharply around late weather updates. Wunderground’s airport history page is the stated resolver, which matters because a reading at the airport can differ from central Wellington by a degree or more in either direction.[3][12]

Historically, late-July Wellington is firmly winter-like: average July highs sit around 12–13°C, daily highs are typically near 53°F/11.7°C, and July is one of the wetter and cloudier months, which tends to cap daytime warmth even when the forecast improves.[2][6][11] That context makes the upper temperature bands harder to reach than mid-range outcomes, but airport observations can still spike if northerly flow and sunshine line up. For comparison, platform mechanics matter here: Polymarket and Kalshi generally charge the spread through market pricing, whereas Betfair and Smarkets add exchange commissions, and KYC access can vary by jurisdiction, which affects who can trade and how quickly liquidity forms around a near-term weather print.[3][7]

The main catalysts are the local forecast updates for Wellington and any short-lived change in wind direction, cloud cover or rainfall timing ahead of the airport’s midday settlement cut-off. Traders should watch MetService and airport observation feeds because even modest shifts from a southerly to a northerly airstream can change the day’s maximum by several tenths of a degree, enough to move a banded market. Weather history pages also show that July warmth in Wellington is usually constrained rather than absent, so the market is less about a broad seasonal call than the exact intraday maximum on a single winter day.[7][12]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in Wellington on July 31? 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

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.

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.