Paris Hit 29°C on July 18, 2026 | Lines.com

Paris recorded a high of 29°C on July 18, 2026, resolving the Polymarket temperature market in favor of the 29°C outcome bucket. The reading was confirmed against the 12:00 noon local time cutoff, triggering a full settlement at $1.00. Traders holding the 29°C position collected in full.

The market opened with an implied probability of just 21% for the 29°C outcome, then surged to 100% as temperature readings aligned with that bucket on July 18. Total volume reached $108,999, with $72,292 traded in the final 24 hours alone. That late-session conviction tells you the market read the thermometer, not the forecast.

Paris Temperature on July 18 Confirmed at 29°C

The 29°C bucket resolved YES after Paris temperatures peaked within the July 18 measurement window. Météo-France data and on-the-ground station readings placed the high squarely in that range. The 12:00 noon local cutoff is the authoritative measurement point for this market structure, and the reading landed cleanly on 29°C.

In the final hours, the market moved decisively. The 24-hour price change of 61.5% reflects traders converging on the 29°C outcome as real-time temperature data made other buckets uncompetitive. The final probability at close matched the resolution outcome exactly at 100%.

Sponsored Partner

How the Market Priced This Outcome

The implied probability at market open was 21%, meaning the 29°C bucket started as a distant possibility among 11 outcome choices. By resolution, that probability had reached 100%. The math doesn’t lie: the market opened skeptical and finished certain. That 79-point swing happened almost entirely on July 18 as intraday temperature data resolved the ambiguity.

Total volume of $108,999 across a single-day temperature market signals genuine trader conviction. Liquidity of $209,211 provided strong price discovery quality. For a hyper-short-duration market like this, that depth is meaningful. Here’s what the market is missing in most post-mortems: the early 21% price wasn’t a failure. It reflected legitimate uncertainty across 11 buckets. The late surge to 100% was the market doing exactly what it’s supposed to do.

Market Performance Summary

• Resolution Outcome: 29°C bucket confirmed YES on July 18, 2026.
• Article-Time Probability: 21% implied probability at market open.
• Final Price at Close: 100% (1.00) at resolution.
• Total Volume: $108,999 with $72,292 in final 24 hours.
• Market Assessment: Underpriced YES at open; correctly resolved by close as real-time data narrowed the outcome range.

What the 29°C Reading Means for Paris Weather Markets

A 29°C high on July 18 sits modestly above Paris’s historical mid-July average of roughly 25°C. The city recorded 30°C on July 4, 2026, in a separate Polymarket market, so the July heat pattern has been consistent but not extreme. No heat emergency threshold was breached on July 18.

For prediction market structure, single-day temperature markets with 11 outcome buckets present a genuine pricing challenge. Early probability distribution across that many choices makes any single bucket look cheap. The binary question of whether a specific degree reading resolves YES is better suited to tighter ranges and shorter bucket intervals.

Forward Signals

• Météo-France forecast data for late July 2026 suggests temperatures could approach or exceed 33°C in coming days, making higher-bucket outcomes more likely in future markets.
• The July 4 resolution at 30°C and the July 18 resolution at 29°C together indicate Paris temperatures are running above the historical July average of 24°C to 25°C this summer.
• Future temperature markets for Paris will likely see heavier early volume in the 28°C to 31°C range based on the established July 2026 pattern.
• The 12:00 noon cutoff structure concentrates risk on morning peak windows, which may diverge from afternoon highs on days with delayed heat buildup.

LINES RESOLUTION VERDICT

CONFIRMED: 29°C

The 29°C bucket resolved correctly, and the market’s late-session price surge proved the mechanism works: real-time temperature data overwhelmed early uncertainty across 11 buckets.

What the market showed: The 29°C outcome opened at 21% implied probability and closed at 100%. The 79-point gap reflects distributed uncertainty at open, not mispricing. Once intraday data confirmed the reading, the market resolved cleanly with $108,999 in total volume and $209,211 in liquidity supporting the price discovery.