Highest temperature in Paris on August 1?

Platform comparison

Market context

Paris’s high on 1 August will be set by the official reading at Paris-Le Bourget Airport, and the market is really about whether that station tops out in the upper-20s Celsius or slips a degree or two either side of that band. Climatology points to a warm but not extreme early-August profile: average August highs for Paris are around 24–26°C, while long-run records for 1 August sit much higher, with one Paris record table showing a 1 August maximum of 35.5°C in 2013 and broader August extremes reaching about 39–40°C in some datasets.[4][7][12]

That historical spread matters because a 0% crowd-implied price usually reflects a platform mismatch, thin liquidity, or stale quoting rather than a literal belief that the outcome cannot happen. On Polymarket, the market currently shows 28°C as the frontrunner at 70%, with 29°C at 19%, and share prices there are quoted as implied probabilities, not decimal odds.[3] By contrast, Kalshi and Betfair-style books typically present prices in different formats and can diverge on fees, spreads, and access: Betfair charges commission on net winnings, while exchange-style venues often have broader KYC and jurisdiction limits than crypto-native markets.[3]

The main catalysts are the live weather feed and any short-notice heat or thunderstorm changes in northern France, because the settlement window closes at 12:00 UTC and the day’s eventual maximum is fixed by the afternoon evolution at the airport station.[13] Traders should watch the forecast trend for Paris on the day itself, especially whether the afternoon ceiling is nudging towards 28–30°C or being capped by cloud, rain, or marine air. The fact that this is settled on a single station, not a citywide average, also means small local variations can matter more than the broader Paris forecast.[3][13]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in Paris on August 1? 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 Polymarket Alternative, 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.

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.

Which platform is accessible globally?

Polymarket is geo-blocked in the US/UK/EU. Kalshi is US-only. Betfair and Smarkets are UK-restricted. Polymarket Alternative has a different geo footprint and routes to Polymarket's order book at 0% fees.