What is the Ice Cream Index? There is an ice cream index in the weather forecast. What does it mean?

The ice cream index, like the beer index and air conditioning index, are business indices used to help companies predict and determine production and marketing plans in advance.

The specifics are: (season) + (one more day for every 1℃/n℃ increase in temperature) can lead to (n% increase in ice cream sales/piece) depending on the unit

< p>ps: I have never seen this kind of weather forecast. .