Tokyo Minimum Temperature on May 25: Market Near Certainty

The market has already priced this one as settled. With a 98% implied probability, traders are betting heavily that Tokyo’s lowest temperature on May 25 lands at 18°C. The remaining 2% is noise, not conviction. Here’s what the measurements are telling us: late May in Tokyo typically brings overnight lows in the 16-to-19°C range, and the current meteorological setup puts 18°C squarely in the crosshairs.

The market question asks which temperature bucket captures Tokyo’s minimum on May 25, 2026, resolving at noon UTC on that date. The 18°C outcome trades at 0.98 (98% implied probability) against a field of alternatives spanning 14°C or below through 24°C or higher. Total volume stands at $32,296, with $25,649 of that trading in the last 24 hours. The market resolves 2026-05-25 12:00:00.

How the Tokyo Minimum Temperature Contract Works

YES on 18°C pays out if Tokyo’s official minimum temperature on May 25, 2026 is recorded at exactly 18°C. NO on 18°C pays out if the minimum falls into any other bracket, from 14°C or below up through 24°C or higher. The responsible measurement body is Japan Meteorological Agency, which records official temperature readings for Tokyo. Resolution follows the JMA-reported minimum for the calendar day.

• YES (18°C): 0.98 price, 98% implied probability
• NO (other outcome): 0.02 price, 2% implied probability

A NO payout requires Tokyo’s minimum to deviate from 18°C entirely. Japan Meteorological Agency data would need to show the overnight low either dropping to 17°C or below, or climbing to 19°C or above. Late May cold snaps can pull readings down, and warm maritime air pushing onshore can lift minimums. Neither scenario commands meaningful market support right now.

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Momentum and Market Signals

The trend score sits at 65.87, pointing toward continued conviction in the 18°C outcome. No 1-hour or 24-hour price change data is available, which means the price has been stable rather than actively repricing. When a market trades this close to certainty without visible momentum swings, the signal is consolidation, not complacency.

Total volume of $32,296 is modest. Volume under $1M means this market can reprice sharply on a single weather forecast revision or a batch of informed traders acting on updated JMA data. The $25,649 in 24-hour volume represents roughly 79% of all trading, suggesting activity accelerated sharply as the resolution date approached. Liquidity of $13,603 provides a reasonable cushion but not an unlimited one.

Key Factors

• The 98% implied probability reflects near-consensus among traders that Tokyo’s May 25 minimum lands at 18°C, consistent with late-spring climatological norms for the city.
• Japan Meteorological Agency is the resolution authority. Any revision to its reported minimum before the noon UTC cutoff would directly move this price.
• The 24-hour volume surge to $25,649 indicates traders are adding conviction positions close to resolution, not unwinding them.
• Thin total volume below $1M means a single well-informed trader acting on a weather model update could shift the price meaningfully before resolution.
• Competing temperature brackets (17°C and 19°C) carry the most plausible alternative probability. Both sit within one degree of the market’s favored outcome.

Lines Analysis: Tokyo’s May Minimum and the Meteorological Setup

Japan Meteorological Agency historical records for late May show Tokyo’s overnight minimums clustering between 15°C and 20°C during this period. The 18°C reading sits near the center of that range. A settled upper-level pattern without major frontal disturbance typically keeps late-May minimums from deviating sharply in either direction. The data doesn’t care about the politics, and the meteorology here is not exotic.

The real NO risk lives in the adjacent brackets. A stronger-than-expected onshore flow from the Pacific could push the minimum to 19°C. A late-season trough dropping south could pull it to 17°C. Japan Meteorological Agency would capture either deviation in its official reading. The market assigns roughly 1% probability to each adjacent bracket, which is low but not zero.

Signals to Monitor

• Japan Meteorological Agency 24-hour forecast updates for Tokyo on the evening of May 24 will sharpen the overnight low estimate and could prompt last-minute repositioning.
• Any surface trough or frontal system moving through the Kanto Plain overnight would push minimums toward the lower brackets (17°C or 16°C).
• Sustained southerly winds ahead of a warm front would be the mechanism for a 19°C or 20°C reading, which is the upside risk case.
• Resolution timing at noon UTC on May 25 means the final JMA reading must be official before that cutoff. Timing of the official report matters.
• Thin liquidity of $13,603 means a late position from a trader with fresh meteorological data could move the price noticeably in the final hours.

Total volume of $32,296 reflects a focused, short-duration weather market rather than a major science or policy market. The data favors the 18°C outcome. The market is pricing uncertainty, not science, and right now both are pointing the same direction.

LINES VERDICT

HIGH CONFIDENCE: EIGHTEEN DEGREES

The meteorological setup for late May in Tokyo is consistent with an 18°C overnight minimum, and 98% market pricing reflects a near-consensus read on a well-understood seasonal pattern. Nothing in the current forecast picture justifies a meaningful challenge to this outcome.

What the market says: 98% probability on 18°C as of 2026-05-24. The market has treated this as resolved. With resolution just hours away, the price is unlikely to move unless a fresh Japan Meteorological Agency forecast shows a surprise deviation.

Key unknown: The single variable that would reprice this contract is a Japan Meteorological Agency evening forecast on May 24 showing the overnight low shifting decisively toward 17°C or 19°C. That is the only remaining catalyst.