。
The weather probably won't turn bad next week.
Literal
Next-week weather [subject-が] go-bad-[thing-こと] [topic-は] is-not [probably-でしょう].
天気がくずれる ('weather turns bad / collapses') is a standard meteorological idiom — 崩れる ('crumble, collapse') applied metaphorically to deteriorating weather. ~ことはない (contrast topic + negative) here functions as 'there's no [possibility] that X' — 'it won't happen that the weather turns bad.'