Yes you can take off in and ride a hot air balloon in the winter.
During the winter and cold weather temperatures the hot air balloon will more easily lift off into the air because of the cold temperatures.
Whereas during the warmer months it usually takes a bit more heat for the hot air balloon to lift off into the air so it's more ideal to fly a hot air balloon during the winter.
That is as long as the air is stable enough which it usually is.
That's the reason the hot air balloons usually take off in the morning because during the morning the air is more stable and ideal for the hot air balloon to take off.