Despite the reviews, I bought one of the emergency air compressors. Well, with the temperature change, I woke up to 4 low tires. And it was raining. I was able to put more air in the tires in the comfort of my own garage. 
So ignore the reviews, it works great!
I bought a similar one a year or so ago from here (Fanttik S100). I’ve used it once or twice. It’s a nice little bit of peace of mind to have it in the back of my vehicle.
edit - and I hope you enjoyed a cup of tea afterwards 
Rainy days and tea go well together 