Before shipping any dragon, I check the weather forecast for the zip code provided and the guaranteed delivery time. UPS standard next day air is usally 10:30am in most areas. I don't use Fedex because only their Priority Overnight is guaranteed before 10 am, their standard overnight may not arrive until 2pm. If the overnight lows are any lower than the mid 50's, I use a heat pack. weather.com gives you the temps throughout the day in 2 or 3 hour increments so you can plan accordingly. If the temps are going to be over 90ºF before noon, I use cool packs. Every situation is different and you need to break out the common sense sometimes. Positioning and ventilation can also affect the heat the dragon gets while in the box. You can always test it out.
Before I started shipping I did some tests just to see what would happen. I lined a box with foam, inserted a heat pack with probe thermometer and put it in the freezer and refrigerator to monitor it throughout the day. It worked pretty good, the freezer was a little extreme but it stayed very warm in the fridge.
I haven't done it yet with cool packs but I will be very soon. It's already in the 90s here! uck