Hydrogen cars also struggle filling at below -10C.
The problem is the hydrogen is transported as a refrigerated liquid, which creates cryo-hazards. In fact, a good hydrogen EV will take about 25-30 minutes to refill at -10C ambient. The other concerning aspect is the cost of a typical refill station. Compressing hydrogen to cryogenic temperatures is not cheap, so most stations use a single compressor and storage plant. The issue is this compressor can only run so fast - typically it runs overnight during down-times - and for the units in Southern California for instance the rate is about one car every 20 to 30 minutes if the station is busy. Not the so-called 5 minute refuel. Look the queues that Mirai owners are experiencing. They're tethered to these stations, no other way around it, whereas at least an EV owner can run an extension lead in most cases!
It is also the case that -10C is not a common temperature for most of the world. Some places experience it during winter, others do have the disfortune of experiencing it for longer, but regardless there are places like the UK where even going below 0C is uncommon. EVs can still charge in -10C weather, the charge rate is just reduced and the efficiency is reduced somewhat by using the battery heater.
For charging on the street, a typical EV with a 40kWh battery will need to charge about once a week to cover commuting uses. So we do not need a density of chargers to match the number of cars. What we do need is dedicated on-street parking bays with EV chargers, about 10-20% of all spaces on a given street should consist of these. About 50% of homes in the UK have access to off-street parking as well, so they can use their driveway or parking bay as they see fit. We'll also need EV chargers at major destinations for people to 'graze' - already many supermarkets and offices have small numbers of chargers but this will need to increase to ca. 20% of all parking bays, perhaps more. This will allow people to charge up while their car is otherwise unused, without having home charging options.