> For the complete documentation index, see [llms.txt](https://climashield.gitbook.io/climashield/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://climashield.gitbook.io/climashield/weather-derivatives/cooling-degree-days-cdds.md).

# Cooling Degree Days (CDDs)

CDDs are a measure of how much cooling is required to maintain a comfortable indoor temperature during the warmer months.

CDDs Season = 15 Dec (Nov) to 15 March

CDD = max (Tn - Tref , 0)

where,

Tref  = A reference temperature(often around 65^degree F or 18^degree C) above which cooling is considered to be required.

Tn = Average Temperature of the nth Day.