I have noticed that it takes longer to raise steam when the ambient temperature is low. The quality of the flame at the burner seems to degrade the colder it gets, and if the gas tank and the refill cylinder are both cold, it is harder to fill the tank, the combined gas laws explain why. If there is a temperature difference between the tank and the refill, filling is easier, cold tank, warmer refil. In order to make lighting up easier, I stand the tank in a little warm water for a few minutes, this usually solves the problem. Jets are quite inexpensive, so I always carry a couple of spares, I have noticed the gas can be quite mucky, depending on manufacturer. Finally, I keep meaning to buy a cheap set of electronic kitchen scales so I can fill the tank by weight, in an effort to take the guess work out of filling up.....