When should I reach out again

Hi, 

Just a quick question, on the 8th of december I cold emailed a head of IBD, whose bank recently opened a IBD office in my hometown asking for a part-time job during my studies. He answered within 5 minutes, we had a nice chat and after showing my resume, talking about logistics etc. he said that they were gonna have an internal discussion - since I basically gave them the idea of a part time employee -  and that they would get back to me. 

I still haven't heard anything, when is it time to email him and politely follow up on our last sent email? Fyi, I know that my colleagues from my last internship texted him excellent references (he worked there before) if that has any meaning. Normally I would just email him now, but I'm not sure if the holidays in between changes anything time-wise.