The Paris temperature market on May 17 tracks whether the city's highest temperature will reach exactly 19°C—a narrow target in spring weather conditions. Paris in mid-May typically experiences highs between 15–22°C, making a precise hit on 19°C unlikely but not impossible in principle. With current odds at just 1% YES, the market strongly reflects trader conviction that this outcome is improbable. Meteorologically, Paris weather in May varies considerably based on Atlantic weather systems, air mass movements, cloud cover, and broader seasonal patterns. Spring in Paris is notoriously variable; a single warm day can be followed by cooler conditions as low-pressure systems move in from the Atlantic. The 1% price reflects the structural difficulty of hitting an exact single degree—numerical weather prediction models rarely provide sub-degree precision, and real-world conditions depend on specific synoptic patterns that cannot be predicted with certainty days in advance.
What factors could move this market?
Paris operates within a temperate maritime climate (Köppen Cfa), heavily influenced by Atlantic weather patterns and the moderating effect of the Gulf Stream on year-round temperatures. May represents a critical seasonal transition month where spring fully asserts itself—day length increases dramatically, solar radiation intensifies as the Earth tilts toward summer, and jet stream patterns shift progressively northward, reducing the frequency of cold continental outbreaks. Historically, Paris in May averages a high of approximately 18–19°C, making 19°C itself a statistically 'normal' outcome rather than an extreme outlier. However, prediction markets price outcomes based on statistical dispersion and uncertainty about real-world conditions, not merely on historical averages.
The YES case for exactly 19°C on May 17 would require a specific meteorological setup: a cool Atlantic trough moving across northern France with substantial cloud cover to suppress afternoon solar heating, or a weak warm high-pressure system delivering mild but not hot conditions. Historical data from Météo-France records suggest May 17 reaches approximately 19°C in about 5–10% of years over the past 50 years, making this a plausible but below-average outcome from a pure climatological perspective. A weak Atlantic ridge with overcast skies could produce this outcome, as could an early-season cool spell before summer warming fully establishes itself.
The NO case encompasses the broader distribution: either notably warmer conditions from an established anticyclone or warm southerly flow (21–25°C range), or cooler maritime conditions from Atlantic low-pressure systems with cloud and rain (15–18°C range). Recent Parisian spring seasons show increased volatility in May temperatures, with weeks ranging from notably cool periods to unexpected warm spells driven by atmospheric blocking patterns. Current climate trends toward warmer springs may slightly shift the distribution toward higher May temperatures.
The 1% YES odds imply traders assign approximately 99% combined probability to outcomes outside the narrow 19°C band, concentrating conviction on warmer or cooler tail scenarios. This extreme pricing reflects either strong model consensus showing non-19°C outcomes, perceived climatological skew in May Paris temperatures away from mid-range, or effects of modest trading volume ($6,337 daily) creating wide bid-ask spreads and potentially inefficient pricing. Weather markets at single-degree temperature resolution inherently reflect profound uncertainty—no forecast model achieves such precision days ahead—making any narrow target inherently improbable.
What are traders watching for?
Météo-France official forecast updated May 16 will provide the most reliable near-term temperature prediction; significant shifts could move market odds substantially.
Actual recorded high temperature on May 17 settles the market; Météo-France observational data is the official resolution source for this market.
Cloud cover and solar radiation on May 17: overcast skies suppress heating (supports YES at 19°C), clear skies drive higher temperatures (supports NO).
How does this market resolve?
The market resolves on May 18, 2026, based on the official Météo-France recorded high temperature for Paris on May 17. YES if the high equals exactly 19°C; NO for any other temperature.
Polymarket Trade is an independent third-party interface to the Polymarket CLOB prediction market exchange on Polygon — not affiliated with Polymarket, Inc. Prediction markets aggregate trader expectations into real-time probability estimates. Every market question resolves YES or NO based on a specific event outcome; traders buy shares of the side they believe will resolve positively. Prices range 0¢ (certain no) to 100¢ (certain yes) and naturally reflect the crowd-implied probability of YES. Polymarket Trade is non-custodial — your funds never leave your wallet. Open the full interactive page linked above to place orders, see order book depth, and execute a trade.
