St. Patrick’s Day marks the peak of a seasonal event celebrated with cult-like intensity by its followers: the appearance of the McDonald’s Shamrock Shake.

The Shamrock Shake is available in the US, Canada, and Ireland from February to mid or late March. It is up to the franchise owner if they want to offer the beverage. This turns the US (and parts of Canada, and Ireland) into a frosty green patchwork of have and have-nots.

McDonald’s does not offer a map or listing of franchisees selling the Shamrock Shake. Devotees must instead turn to the unofficial trackers, such as ShakeLocator.com or ShamrockShake.com.  Find yours today!

Note: They seem to be hard to find here in SoCal.  Someone said they are available at the McDonald’s in North Hills near Balboa and Parthenia!