Sometimes my dog barks during the night.

Literal

Sometimes, my dog [topic-は] midnight [genitive-の] during [at-に] barks.

A straightforward sentence. 時々 ('sometimes') marks frequency. 夜中の間に ('during the middle of the night') uses 間 ('interval / during') with the time marker に. 吠える (ほえる, 'to bark / to howl') is the standard verb for animal vocalizations. The polite form 吠えます keeps it in everyday conversational register. A relatable pet-owner observation.