I work as an outdoor educator in Ontario and spend every day outside. These gloves are my go to gloves when it's colder than -10C out (pretty frequently in the winter), I've worn them in temps down to -25C and have been completely comfortable, and they could easily handle colder. I wear them on the snowmobile while grooming cross country ski trails and have never had issues with the windchill. You will definitely lose some mobility with these gloves in comparison with lighter gloves, but that's the trade off for how warm they are. I followed the size guide and bought a medium & found them to be a great fit. Out of the bag these were a bit stiff but after a day they were broken in & now feel really comfortable. One thing I've noticed is that the velcro that connects the liner to the shell can get a little itchy at times. Overall, great gloves that seem like they'll last a long time.