This market asks whether Tokyo's daily high temperature on May 17 will be exactly 21°C—a hyper-specific forecast in a continuous variable. May represents late spring in Tokyo, with typical daily highs ranging from 22–27°C depending on weather systems and seasonal patterns. The 0% odds reflected in current trading suggest market participants assign minimal probability to this exact outcome. Weather temperatures rarely match precise point values; even a forecast of 21°C typically carries uncertainty of ±2°C. Traders appear confident the actual high will diverge from this target, whether climbing higher with warming trends or dipping lower than the stated value.
What factors could move this market?
Tokyo's May climate sits at the cusp between spring and early summer, with atmospheric conditions becoming progressively warmer as the month advances. Typical May highs range from 22–27°C, shaped by solar radiation intensity, upper-level wind patterns, and moisture transport from the Pacific. The figure of 21°C places this market at the cooler end of May's normal distribution—a temperature more typical of early May or days disrupted by weather systems that suppress warming. Several factors could theoretically push toward a cooler outcome: a low-pressure system moving through central Japan, unusually strong cloud cover reducing solar heating, or inflowing cooler air masses from the north. Conversely, the likelihood of NOT hitting exactly 21°C is far higher given May's inherent seasonal warmth. Most outcomes will be either above 21°C (typical for mid-to-late May warming trends) or below it (requiring a significant cool anomaly). Historical Tokyo May records show daily highs clustering around 23–26°C, with 21°C readings appearing on roughly 5–10% of May days and usually linked to specific weather systems. The 0% odds reflect both the inherent difficulty of matching a continuous variable to a single point and trader assessment that May 17 is unlikely to produce conditions cool enough to cap warming at exactly 21°C. Official temperature readings come from the Japan Meteorological Agency's Tokyo station, measured at standard height and time according to WMO protocols.
What are traders watching for?
Market closes May 17, 00:00 UTC; Tokyo high typically recorded 14:00–16:00 JST same day
Japan Meteorological Agency official reading required; rounding rules apply to final determination
May 15–16 temperature patterns indicate seasonal trend and baseline for May 17 conditions
Synoptic forecast: monitor low-pressure systems and frontal boundaries May 15–17 period
Morning satellite and radiosonde data May 17 will finalize insolation and cloud expectations
How does this market resolve?
Market resolves based on the Japan Meteorological Agency's official highest temperature reading for Tokyo on May 17, 2026. The outcome requires an exact match to 21°C; readings of 20.9°C or 21.1°C result in NO.
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.
