I have pulled 9 mile, 10%+ grades, low gear, 25 mph, full throttle, 115 heat, air conditioner on max, and the Ford gauge does not move :R
Anyway if yours stays 230/240 you are fine. What is your rpm when this happens because you should be 3000+ during a hard climb. Use your gears, all of them! Slow down a bit and drop a gear.
If the temp is approaching 250 I would slow up and drop down another gear. Last resort is low gear and turn on the heater but that is desperate. If you do pull off be sure to keep it running. Read the manual for best recommendations to sit in neutral or park, idle or fast idle etc. 50/50 coolant boils at 265/270 with a 15 psi cap.
Check options and specs for factory oversize radiator or larger transmission cooler if the trouble persists or gets worse.