Is it ok to use "increased to a peak" instead of "reached a peak" with regard to the following sentence?
"Viewing figures for the 9:30 news increased to a peak of 3.8 million in May"
Increased to a peak of is grammatically correct but the use of increased may cause the reader to wonder if it decreased after it reached a peak, or if it stayed at that level.
Reached a peak of is more usual. Peaked at is also good.