How daily temperature markets settle
A plain guide to the numbers behind a daily high or low market. Always read the exact contract rules on the exchange before you trade; they decide, not this page.
1. The settlement number
Most daily high and low markets settle on the final daily climate report for one named station (for example KMDW, not "Chicago"). That report gives the day's high and low in whole °F.
2. The climate day
The climate day runs midnight to midnight in local standard time. During daylight saving time that means 1:00 AM to 12:59 AM the next night on the clock. A late-evening warm spike can count for today.
3. Preliminary vs final
A preliminary report usually comes out late afternoon and a final one the next morning. The final can differ from the preliminary and from the highest reading you saw during the day. Check which one the contract uses and when the exchange settles.
4. Why live readings can mislead
- 5-minute readings are sent in whole °C, so one reading can mean two whole °F values. Use the converter.
- Hourly reports carry tenths of °C and pin an exact °F.
- The daily high can fall between readings. The 6-hour max and the daily summary capture it.
5. Brackets
Bracket edges are inclusive or exclusive depending on the contract (for example "86–87°F" vs "above 87°F"). Read the strike wording for each bracket.
6. Corrections and disputes
Reports are sometimes corrected. Each exchange has its own rules about which version counts and how late a correction is accepted.
See also: Guide · °C→°F converter · Station history