I don't live in a severe weather climate, but my laundry area is in the attached garage. Many homes here have this arrangement, which offers several advantages vs. an "indoor" laundry room:
1. Garage slab is six inches lower than the house floor. If there is a leak, water stays away from the house. Furthermore, the garage slab is imperceptibly sloped toward the driveway/street. If you dump a bucket of water on the floor, it will flow towards the street.
2. Dryer heat stays out of the house and keeps it cooler in summer. We don't need A/C here in summer due to the mild climate, and keeping heat out of the house helps.
3. Not a deal breaker for me, but some prefer to have the noise out in the garage.
Garage laundry areas tend to be more popular in single story homes. In newer two story homes, the trend is to have an upstairs laundry area (sometimes with no drain or pan below the machines---yikes), which can lead to flooding and vibration (FL) issues.
Building code requirements specify that a garage here must have either windows, or else ventilation grates, presumably to moderate summer heat. My garage has the grates, some are a foot off the floor and some are six feet off the floor. When we are having cold spells here (defined as 30-40F overnight), the garage can become surprisingly cool because of the grates: recently when it was 33F overnight, I checked my garage thermometer and it was 48F inside the garage. We occasionally have record frosts down to the mid-20s, but I never bothered to check the garage temp to see how cold it gets in that situation.
Never had any washer/dryer issues (modern Frigidaire 2140/1442 gas dryer) operating in a 50F garage. Of course, since my simple FL has no internal heater, putting hot water into a 50 F machine will lower the wash temp. I don't tamper with my water heater temp, it's about 140F, but in really cold weather I will prime the hot water line first before starting the machine. The laundry area shares a common wall with the kitchen sink and DW, so I open the sink tap until it's good and hot, which primes the hot water pipes in the wall. About the only thing not primed is the supply hose from wall to washer, so if it HAS to be hot, I start the washer empty, wait until the inside is all steamed up, then I hit Cancel/Drain, empty the washer, and then fill with clothes and restart.
The major impact for me is that I never wash on Cold in winter, but this more has to do with the ground water being very cold, and my machine lacking Auto Temp Control, than the actual garage temp. Apparently Frigidaire has modified the 2140 so that it now has Auto Temp Control, at least for Cold: there are now two Cold settings, Auto Cold and Water Line Cold. I read the user manual online and cannot determine whether ATC kicks in only for the Auto Cold setting, or whether it's also in play for Hot and Warm, in which case you can't undo it for Hot and you are stuck with their interpretation of hot.
Note: growing up in San Diego, I occasionally saw washer/dryers housed in a covered breezeway (that is, a roof overhead, but otherwise open to elements). Some friends of mine have a two-home property (detached garage was converted to a one-bedroom cottage,originally for the grandparents). The rear (grandparent) house had a screened=in porch (but no windows, always open to breezes) and the laundry machines were in this area. The rear house is now rented to a building contractor who enlarged the house by enclosing the former screened porch, which displaced the washer/dryer. He built an outside annex against the side of the main (front) house so that it's enclosed on top and sides. The front is a simple bamboo rolldown shade, and the stacked machines are doing fine.
The property is owned by a high school friend who no longer lives in the area, but she uses the front house as an occasional weekend home. She rents the back house to the contractor (likewise, a high school friend) who has done all sorts of upgrades on both houses, for which she simply pays for the supplies. In return, I suspect she charges way-below-market rent. The house is about six blocks from the ocean, so you'd think there would be salt/corrosion problems, but so far the machines look fine and operate without major issues. [this post was last edited: 12/19/2011-10:08]