Trade: Highest temperature in Chicago on May 15?

Market context

On 15 May 2026, the highest temperature recorded at Chicago O'Hare International Airport will fall within one of several defined ranges. The market currently shows 0% implied probability across all temperature brackets on Polymarket's order book, indicating either minimal trading activity or a technical settlement issue rather than genuine market consensus. Resolution will depend on Wunderground's historical weather data for that specific date, which becomes available after the settlement window closes at midday UTC.

Chicago's May temperatures typically range from 60°F to 80°F, though the city has recorded highs exceeding 90°F in mid-May during warmer years. The 30-year average high for 15 May sits around 73°F. Historical precedent suggests most outcomes cluster in the 70–85°F range, with extremes either side occurring infrequently. The absence of any meaningful probability distribution on the order book suggests traders are awaiting either clarification on market mechanics or sufficient liquidity to establish initial price discovery.

Traders monitoring this market should track seasonal weather pattern forecasts as May 2026 approaches, particularly any signals from the National Weather Service regarding high-pressure systems or unusual warming events affecting the Midwest. The settlement mechanism's reliance on Wunderground's archived data means the outcome becomes deterministic once the date passes, eliminating forecast uncertainty entirely. Current zero probabilities likely reflect the market's nascent state rather than any substantive view on temperature outcomes.

Resolution source

This market settles from the official outcome published at https://www.wunderground.com/history/daily/us/il/chicago/KORD. A proposer submits the final result to the UMA optimistic oracle on Polygon; the two-hour dispute window closes and payouts clear in USDC.

How to trade this market step by step

The mechanics for trading "Highest temperature in Chicago on May 15?" are the same as any other PolyGram event contract. Each YES share resolves to $1 if the event happens, or $0 if it doesn't. The current price between 0¢ and 100¢ is the market's probability estimate, set live by the order book.

1. Sign in on polygram.ink with your email — no full KYC under $1,500 lifetime trading volume.
2. Deposit USDC on Polygon (lowest fees, ~$0.01 per transaction) or Ethereum. Funds credit after 12 confirmations.
3. Pick a side. Buy YES if you believe the event will happen; buy NO if you think it won't. The current YES price reflects the market's collective probability.
4. Size your position. If you stake 100 USDC at 50% YES, you'll receive shares that pay $200 if YES resolves true — a 100% gross return. If NO resolves, your shares are worth $0.
5. Set risk controls (optional). Stop-loss, take-profit, and limit-order types all supported. Use the trade ticket's slippage box to cap your maximum entry price.
6. Wait for resolution. When the event resolves on-chain via the UMA optimistic oracle, the winning side settles to 100¢ automatically and USDC hits your balance within seconds. Withdrawable to any wallet you control.

How active is this market?

$16K in lifetime turnover and $79K of resting liquidity puts this market in the below the median by volume for weather contracts on PolyGram. Order-book depth is exceptional — among the deepest order books in the category.

Last 24 hours alone saw $16K in turnover, well above the lifetime daily-average for this market — a clear sign of news catalysing trader activity right now.

The market has been open for under a month — fresh enough that information asymmetry remains a real factor.

Higher-volume markets tend to have tighter spreads and faster price discovery — meaning the displayed YES/NO percentages are more likely to reflect the true crowd-implied probability rather than a single trader's directional view.

Key terms

YES / NO share

A binary outcome token that pays $1.00 if the underlying claim resolves true (YES) or false (NO), and $0 otherwise. The market price between 0¢ and 100¢ is the implied probability.

CLOB

Central limit order book. The matching engine that pairs YES buyers with NO buyers (effectively the same trade). Polymarket's CLOB on Polygon executes trades on-chain via the conditional-tokens framework.

Liquidity

USDC capital sitting in resting limit orders inside the order book. Deeper liquidity means smaller slippage on large trades and a tighter bid-ask spread.

UMA optimistic oracle

The on-chain dispute system that settles each Polymarket market. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution.

Slippage

The difference between the displayed mid-price and your fill price. Affects market orders most; limit orders avoid slippage but may take time to fill.

Conditional token

ERC-1155 outcome share issued by Gnosis Conditional Tokens on Polygon. The token type that resolves to $1.00 or $0.00 at settlement.

See the full prediction-market glossary →

Frequently asked questions

Risk and regulatory note

Prediction-market positions can lose 100% of staked capital. Outcomes are uncertain by definition — historical accuracy of crowd-implied probabilities is high in aggregate but not for any single market. PolyGram does not provide investment advice. Trade only with capital you can afford to lose.

Regulatory status varies by jurisdiction. Germany, the United States, and most EU countries treat Polymarket-style event contracts under one of three frameworks: financial derivative, gambling product, or unregulated novel asset. Consult local counsel before trading.

Related prediction markets

Explore more prediction market odds and trading opportunities on PolyGram:

• All weather prediction markets
• How prediction markets work
• Browse all prediction markets on PolyGram
• Top prediction market traders
• Back to PolyGram home