I’ve had trouble using these for outside lights if it’s cold. I’m talking about for the lights by the doors into the house. They either take a long time to come on or don’t come on at all sometimes. Anyone else have this problem? Are they not recommended for use outdoors?
Yes, I have noticed this on the bulb on our back porch. On cold days it seems dimmer for a while. I think they just need to warm up to full brightness; I assume they are okay for the outdoors, as we haven’t had problems except the dimming. I’m sure I’ll be corrected if i’m wrong. 
I’ve never had them not come on at all though… although I have had to double check when it seemed no light was shining, only to see the bulb was on, just not that bright.
you should read the packaging carefully - some compact flourescents are marked “indoor only” or “not for exterior use” for precisely the symptoms you describe.
look for “indoor/outdoor” or “interior/exterior” on the package next time you buy compact flourescents; if there is not an “indoor only” or “indoor/outdoor” type ranking with the brand you prefer, the slightly higher wattage (less energy efficient) ones are going to be better, if not designed, for outdoor lighting.
also remember that compact flourescents (and the not-so-compact ones as well) do not get along well with dimmer switches. if you want to keep the dimmer, yet have more energy efficient lighting, go with l.e.d’s.
edited to add: if it is cold enough, (in my experience, colder than -5c) even “outdoor” rated compact flourescents will take a minute or two to warm up to full brightness.
Excellent. Thanks.