What is the lowest outside temperature that is suggested when paving with asphalt?

it will vary due to your region.your best answer will come from your local blacktop plant.

ask them whon they shut down for the season

The DOT requirement for most applications in Georgia is that the temperature must be "40 degrees and rising". As a practical matter, thick base courses can be put down several degrees colder, but not on a frozen subgrade. And thinner surface courses need to be done when it's a little warmer, especially when hand spreading is required. If the asphalt mix cools too quickly, poor density and a rough surface will result.