Why is my WiFi sometimes really slow, and other times really fast? by Westley Julio
Answer by Westley Julio:
Any number of causes. Also, I’m assuming “slow” and “fast” is referring to perceived performance of webpages and/or internet connected applications.
Intermittent interference from other Wi-Fi and non-WiFi devices can put the brakes on your connection. You may need to identify interference sources and/or change channels.
Your internet connection may be saturated due cumulative use by cabled devices.
Your ISP, like many others, oversubscribed your connection; you slow down during peak usage periods.
You have a local computer performance problem that’s manifesting as slow wi-fi performance. See if other devices have the issue the same time as your computer does.
Clients you are not aware of are connecting to your network.
Your router or other related network equipment is malfunctioning.
What I would do is try connecting to your router with a cable when you have poor Wi-Fi performance. If this solves your issue, you likely have an actual Wi-Fi problem. If not, evaluate other sources as outlined above.