Air carrier Captain reported a cockpit window malfunction during cruise flight; resulting in a loud cockpit air noise. The flight diverted to an alternate airport and landed overweight.

Narrative

Operated flight to ZZZ1; en-route we just started climb to 320 leaving 300 when a pop followed by a loud squeal occurred in flight deck. Pressurization remained fine. We descended back down to 300; and slowly the squeal went away. Contacted dispatch/Maintenance Control; were informed of previous history on this mx (Maintenance) item a couple of weeks prior. FO and I agreed to continue for now and asked dispatch to send new clearance staying at 300 rest of flight. While discussing the issue and actions with the FO further I realize there was a very loud unusual gushing of air noise now below the CA number 2 window. FO and I agreed to do a precautionary divert to ZZZ which was right ahead. Let Dispatch know; ran over QRG (Quick Reference Guide) divert guide; ran overweight landing checklist; let FA's know; let pax (Passengers) know. Landing was fine. Debriefed in detail with FO. Debriefed with Chief Pilot.