With lows here in NYC (past two night) of 15 and 23, have had to hold off on shipping. Once it hits above 30 it's go time.
Minneapolis next week it will be -10 to 5 above for around 72 hours , but really if you ship anything 25 degrees and above should be ok for delivery in trucks for the day , however where you are in trouble is the delivery release at noon to your porch and it sits til you get home at 5pm
100% this. UPS and FedEx handle millions of packages a week and plenty of them contain fluids that will freeze - they generally don't let packages sit on trucks or out in the cold for long enough for this to happen. The biggest risk by far is that the box gets delivered at 10am and sits out all day on your porch - that will freeze a beer when the temps are low. It has to be really cold for the beer to freeze while with fedEx or UPS since it is usually moving between sorting facilities and onto trucks with a ton of other warm packages that came from indoors providing thermal mass. That said, -10 to 5 is really really cold, so not a good time to ship!! My general rule is pretty much the same as yours - overnight lows above 20, with daytime highs around 30 are absolutely fine, but any lower and you are taking a chance. The other potential issue is if you are shipping over the weekend. Packages can get loaded into trucks and left sitting in the trailer for a day or two, so try to ship on a Monday if you can so the box isn't sitting still for the weekend (just in case it sits still in the cold...)
OP, there are some other threads on the topic as well. Might be interesting for further reading. Good luck. http://www.beeradvocate.com/community/search/32007256/?q=cold&o=date&c[title_only]=1&c[node]=27
Yup, but this thread is probably the best one on the topic: http://www.beeradvocate.com/community/threads/cold-weather-trading-winter-shipping-thread.136681/
A lot of variables, so hard to give an exact cut off point, but generally speaking, I usually play it safe and wait for a few days if it is going to be sustained well below freezing (10-15 and worse). That being said, the boxes usually keep moving too much for it to be an issue. Like @pagriley said, the biggest issue is when it stops moving (ie-sitting at your door). You can throw some disposable hand warmers inside the box if you really are worried/need to get it out.
