Since you didn't mention, I have to ask, is this latency all of sudden, or has it been slow for a long time?
If its the former, a few things to check would be recently installed applications or possibly unnoticed malware. To check what programs/apps are using bandwidth, from an elevated command, you can use netstat -a. This will show you all active TCP or UDP connections. To check for and eliminate possible malware, use Malwarebytes (free version is good, but obviously the paid-for version offers more tools).
If the problem has been happening for a long time, consider the possibility that the connection in question may just be slower than other places you frequent. In other words, you may have a low-speed connection, whereas the local coffee shop could have high-speed. You might also do a tracert -d to a sight you frequent. Trace Route will show you all hops along the way to the destination. This can pinpoint where you're connections are lagging.
If we're talking about WiFi, it is possible that you've recently introduced appliances that are interfering with the signal. Common appliances are phones, microwaves, refrigerators. Also, with today's tech, some appliances are now network-capable, and such appliances can be hoarding your bandwidth. WiFi analyzers can help with this.