Not Peeing at night

Hi, my lo is 4 months old. She is not passing urine almost the entire night for 6-8 hrs. She sleeps after a feed at 6:30pm, wakes at 12am. After I changed the nappy at 1am and woke up around 4-5am there’s already a pee that I think twice or thrice sya nagpee. She’s BF. Her Pedia said na hindi naman sya dehydrated every time na magpapacheck up kami. Did anyone face such a problem?? Pls help is it due to and hot climate?