The outside temp isn't really going to affect whether the glow plug ignites or not. Make sure you're holding the glow plug against the head securely when checking it cause it has to be grounded properly to ignite and you have to hold the ez start button for a few seconds to ignite the plug. The Ez start 2 is a lot better than the first one but it would be a pretty good idea to pick yourself up a seperate glow igniter which does come in handy at times...