This prediction market tracks whether Tokyo's minimum temperature on May 17, 2026 will be exactly 20°C. The current YES odds of 0% reflect trader consensus that this precise temperature threshold is unlikely to occur during the overnight period. Tokyo in mid-May typically experiences overnight lows between 15°C and 18°C, with occasional variations depending on weather systems and seasonal patterns. The market relies on official readings from Japan's Meteorological Agency, making it fully resolvable and free from ambiguity. A minimum of exactly 20°C would represent an above-average overnight low for this season in Tokyo, requiring either unusually warm air masses to dominate or weak radiative cooling due to cloud cover and wind patterns suppressing temperature drops. The 0% odds indicate that market participants view this outcome as very improbable—not impossible in a technical sense, but sufficiently unlikely that they assign near-zero probability. Weather precision markets reflect the narrow nature of specific temperature targets; a forecast range like 18–22°C would be far more probable than an exact value. This market closes on May 17 at midnight UTC, when official meteorological data will definitively resolve the question.
What factors could move this market?
Tokyo's climate during mid-May sits at the cusp between spring and early summer, with wide variability in overnight temperatures driven by Asian weather patterns. The city's geography—an urban heat island in a coastal metropolitan area—means nighttime lows are often 2–3°C warmer than surrounding rural areas, a phenomenon that shifts the probability distribution for precision temperature markets. Historical May 17 data from the past two decades shows Tokyo's minimum typically ranges between 14°C and 22°C, with modal outcomes clustering around 16–17°C. A low of exactly 20°C falls in the upper quartile of this distribution, making it rarer but not unprecedented. The specific date carries significance: late May transitions into tsuyu (rainy season) in Japan, during which atmospheric moisture and cloud cover can trap heat and suppress overnight cooling cycles. Wind patterns from the Pacific or East China Sea, combined with the strength of any high-pressure system present on May 16–17, will determine whether radiative cooling can drive temperatures downward or whether warm air masses prevail. Traders assigning 0% probability to this outcome implicitly forecast that Tokyo's overnight minimum will diverge significantly from 20°C in either direction—a bifurcated expectation where neither significantly colder nor significantly warmer seems likely to concentrate exactly on this value. The complete absence of YES liquidity suggests market participants view this threshold as neither a meaningful meteorological milestone nor a probable outcome. Some traders may interpret 20°C as warm relative to typical May lows; others may find the exact-value constraint too restrictive compared to range-based markets. Meteorological forecasts released through May 17 morning will drive information arrival; most agencies update overnight low predictions through early morning based on overnight conditions and satellite data. For YES resolution, Japan's Meteorological Agency must record a daily minimum of precisely 20°C or per the market's technical specification. The modest $3,465 trading volume combined with 0% odds suggests this is a low-conviction market, primarily of interest to weather enthusiasts or algorithmic traders testing prediction models.
What are traders watching for?
Japan Meteorological Agency's official May 17 overnight low reading; final forecast updates issued May 17 morning.
Cloud cover and wind patterns May 16–17 overnight; strength of high-pressure system determines cool-down potential.
Historical May 17 minimums in Tokyo; 20°C falls in upper range of typical mid-May overnight lows.
Urban heat island effect; Tokyo metro area overnight lows typically 2–3°C warmer than surrounding rural regions.
How does this market resolve?
Market resolves on May 17, 2026 at midnight UTC based on Japan's Meteorological Agency's official minimum temperature reading for Tokyo. The question resolves YES only if the recorded low equals exactly 20°C.
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.
