Seoul June 30 Low Temp: Will 21°C Hit?

A single-day temperature market for Seoul is moving fast. The 21°C outcome has surged to 64.5% implied probability, with the YES price climbing more than 27 points in 24 hours. That kind of momentum on a 24-hour weather market means traders have seen something specific: a forecast, a model run, or a radiosonde reading that lines up with this exact threshold.

The market question is precise: what is the lowest temperature recorded in Seoul on June 30, 2026? YES resolves if the overnight low hits exactly 21°C. The YES price sits at $0.65, the NO price at $0.36, and the contract closes at 12:00 UTC on June 30. Total volume has reached $4,970, with $3,997 traded in the last 24 hours alone.

How the Seoul Temperature Contract Works

This contract resolves on a single observed measurement: the lowest temperature logged in Seoul on June 30. The resolution source is the market operator, drawing on official meteorological data. Eleven outcomes compete, from 16°C or below up to 26°C or higher, each priced independently.

• YES (21°C) is priced at $0.65, implying a 64.5% probability that the Seoul overnight low lands exactly at 21°C.
• NO (any other outcome) is priced at $0.36, implying a 35.5% probability that the low falls at 20°C, 22°C, or any other listed value.

For NO to pay out, the Seoul low must register anything other than 21°C. Late June in Seoul sits in the early monsoon transition. The Korean Meteorological Administration typically records overnight lows between 19°C and 24°C during this window, depending on whether the Changma front has arrived. A single degree of deviation from 21°C is all it takes to flip this contract entirely.

Sponsored Partner

Momentum and Market Signals

The combined momentum signal here is hard to ignore. A 78.57 trend score alongside a 16.5% one-hour gain and a 27.5% 24-hour gain points to a sharp directional reprice, almost certainly driven by updated short-range forecast models. When a weather market moves this fast this close to resolution, traders are typically reacting to a numerical weather prediction output that tightened the probability distribution around one outcome.

Total volume is $4,970 with $3,997 traded in the last 24 hours. Liquidity stands at $11,495. Volume is well below $1 million, which matters: this market can reprice sharply on a single new forecast or an early morning temperature reading. Thin markets amplify signal noise. One confident trader with access to a fresh KMA model output can move the price significantly.

• The 1-hour gain of 16.5% and 24-hour gain of 27.5% together form a strong bullish momentum signal, most likely driven by a new short-range forecast output favoring a 21°C low.
• Total volume of $4,970 is thin. Price moves here reflect conviction from a small number of traders, not broad market consensus.
• Liquidity at $11,495 is adequate for the contract size, but a single large bet can still shift the YES price meaningfully before close.
• The contract resolves in less than 24 hours. Every new forecast model run between now and June 30 noon UTC is a potential repricing catalyst.
• Late June Seoul climatology places overnight lows most frequently in the 20°C to 23°C band. The 21°C outcome is the modal forecast for this date.

Lines Analysis: Seoul Low and the 21°C Thesis

The case for 21°C rests on where Seoul’s overnight lows cluster in late June. The Korean Meteorological Administration’s historical record shows the city frequently bottoms out in the low 20s during the pre-Changma and early monsoon window. Current short-range models, as reflected in the sharp price move, appear to be pointing directly at 21°C as the most likely minimum for June 30. The market is pricing a tight distribution around this value.

What makes NO real is the precision requirement. Exact-degree markets are inherently fragile. The Seoul low landing at 20°C or 22°C is entirely plausible. Urban heat island effects, cloud cover timing, and whether the monsoon front advances overnight all shift the minimum temperature by one to two degrees. The KMA observing network is dense, but the resolution threshold is a single integer. A 20.6°C reading rounds differently depending on the data source and rounding convention used for resolution.

• A KMA official morning temperature report showing exactly 21°C would confirm YES and likely push the price toward 90%+ before close.
• Any updated numerical weather prediction model shifting the forecast low to 20°C or 22°C would trigger a sharp NO reprice given thin volume.
• Monsoon front position overnight on June 29 to 30 is the primary physical driver. Earlier arrival means cooler, wetter air and a lower minimum.
• The resolution source and rounding convention matter. Traders should verify whether the operator uses KMA Automated Surface Observing System data or manual station records.
• Related market pricing for 2026 global heat ranking at 66% probability supports a warmer-than-normal baseline for Northeast Asia, which slightly favors the higher end of the Seoul low distribution.

The data favors 21°C as the modal outcome for June 30 in Seoul. Total volume of $4,970 reflects a small, informed trader pool reacting to real-time forecast data. The market is pricing a tight distribution, but exact-degree resolution means one degree of forecast error flips the contract. The momentum signal is clear. The execution risk is the precision of the threshold.

LINES VERDICT

LEANING YES, HIGH PRECISION RISK

Seoul’s late-June climatology and the sharp recent price movement both point toward 21°C as the most likely overnight low. The margin for error is exactly one degree in either direction.

What the market says: 64.5% probability that Seoul’s June 30 low hits exactly 21°C. The thin volume means this price can move fast on any new forecast output before the noon UTC close.

Key unknown: The Korean Meteorological Administration’s final overnight low reading for June 30, and whether the resolution operator uses rounded or raw station data to determine the exact outcome.

Scientific Context: Seoul Late-June Temperature Climatology

Seoul sits at roughly 37.5°N and experiences a humid continental climate with strong monsoon influence. Late June marks the transition into Changma, the Korean rainy season, which typically delivers increased cloud cover, elevated humidity, and overnight lows that cluster between 19°C and 24°C. The 21°C to 22°C band is historically the most common overnight minimum for this date range. Urban heat island effects in central Seoul tend to push observed minimums 1°C to 2°C above rural surroundings, which is already factored into KMA station data from the city center. A market priced at 64.5% for a single integer outcome in this window is not unreasonable given the climatological distribution, but it remains a high-precision bet on a continuous variable.