I know we are now into wonderful Spring weather and I am about to go for a run on Winter Hill but when we had those sub-zero temperatures I would always take fully charged phone and my sol survival bag, running in microspikes (a bit awkward for the tarmac parts as I ran from home so had a couple of stretches on the road which had cleared of ice and snow).
Re ViewRanger, I found it immensely useful when walking the GR36 in France as I could download the maps where I had access to wi-fi onto my mac mini. I didn't need it so much on the signposted GR36 but it came into its own when making my way back off the GR to where I was to stay on my final night which had rail connections back to Caen (the GR36 goes all the way from the ferry port of Ouistrahem down to the Pyrenees - I had two weeks on the northern section)