In the past LEDs in Minnesota, did not work well, they were very expensive and did not melt snow. The prices have come down over the last two years and for a couple of specific uses are now a useful/viable option.
Downlighting out of trees – A costly and time consuming activity is switching out lights that are mounted high up in trees. By switching the lights to LEDs you can forget about having to replace bulbs for a couple of decades. The only caveat being that you need to make sure you have a good watertight fixture or you risk water damaging your new expensive LED bulbs.
Path or Area Lights – These often use bi-pin style bulbs and manufacturers now have LEDs that will fit most area lights we use. The biggest savings with these lights is if a system is designed around using LEDs. If designed for LEDs, the system can use a smaller transformer and wire size, creating potential saving the customer money on the orignal install and on electricity use of the system.
All this comes with the knowledge that LEDs are a still relatively new technology, and it will take some time to see if they really last decades outdoors.