What is the maximum temperature at which cream will still whip successfully?
The ideal temperature for whipping cream is between 35 degrees F and 50 degrees F (1 2/3 degrees C to 10 degrees C).  In order to maintain this temperature, you may want to chill your bowl and beaters in your fridge until cold, but you should be able to whip cream just fine as long as you do not let it rest once you remove it from the fridge.

Above 50 degrees F (10 degrees C) you won't be able to whip your cream.