Cath still tries to enjoy the summer by relaxing on the beach, but being a polar bear, this type of climate isn't suited to her species, as she's used to living in polar environments.
Even though Cath considered bringing ice packs with her to try and cool off (being stubborn by nature), it's an unusually hot summer and melts quickly, meaning Cath can only enjoy a short time on the beach before she can't stand it.