。
Compared to that, her mood has been pretty good lately.
Literal
That [compared-に比べ] recently her [gen-の] honorable-weather [topic-は] fine.
に比べ is the masu-stem form of に比べる 'to compare to,' used conjunctively in written style. お天気 'weather' is used figuratively for 'mood / disposition' — the standard metaphor where someone's emotional state is described in meteorological terms ('it's stormy in the office today'). 良好 'favorable / good' is formal/written vocabulary, stiffer than いい. The honorific お softens the figurative use.