When:
July 3

Where:
Everywhere

First occurrence:
.?.

You can either just celebrate one day or celebrate the plural form “Air Conditioning Appreciation Days” which lasts about 44 days.
These days fall on the same days as the Dog Days.
Which is fitting, because the Dog Days are often the warmest days of the year on the Northern Hemisphere.

#AirConditioningAppreciationDays

• http://airconditioningdays.com/