Step 1 — Determine if the latency is Wi-Fi or WAN
The first question is whether the latency is in the wireless link or in the internet connection itself. Test ping latency to the default gateway (your router or firewall) — if that's low (under 5ms) but ping to an internet IP is high (over 100ms), the problem is upstream of the AP. If gateway ping is already high, the problem is in the local network or the Wi-Fi link itself. This single test rules out half the problem space immediately.
Step 2 — Check channel utilization at the AP
High channel utilization is the most common cause of latency on a Wi-Fi network. When the channel is saturated — typically above 70% utilization on 2.4 GHz or above 60% on 5 GHz — every frame has to contend for airtime, which adds latency before data is even transmitted. In TekFidelityIQ's RF Intelligence view, look at channel utilization per AP per band. If a 2.4 GHz channel is running at 80% and you have clients on it, that's your first place to intervene: move clients to 5 or 6 GHz, or change to a less congested channel.
Step 3 — Check client SNR and association rate
A client with weak signal-to-noise ratio (SNR below 20 dB) will automatically drop to lower MCS rates to maintain the connection — reducing throughput and increasing the time each frame occupies the channel. Check which clients are associated at low rates. If a client is far from an AP or obscured by walls, it may be stubbornly sticking to a distant AP instead of roaming to a closer one (the 'sticky client' problem). This introduces high per-client latency that can affect everyone else on the same AP.
Step 4 — Check for interference
Non-Wi-Fi interference on 2.4 GHz (microwave ovens, Bluetooth devices, baby monitors, DECT phones) can cause sporadic, hard-to-reproduce latency spikes. The symptom: latency spikes appear during specific times of day (lunch hour = microwaves, office occupancy = Bluetooth headsets). If moving clients to 5 GHz resolves the issue, 2.4 GHz interference is likely the culprit. TekFidelityIQ's RF Intelligence layer shows neighbor network density by channel and band, which helps identify congestion from nearby networks even if non-Wi-Fi interference needs a spectrum analyzer to fully characterize.
Step 5 — Check AP and WAN health
Finally, check whether the AP itself is healthy. APs under memory pressure or running buggy firmware can introduce latency at the hardware level. TekFidelityIQ tracks AP uptime, reboot events, and firmware versions. An AP that rebooted three times in the past week is worth investigating. Also check WAN latency and packet loss to a reliable external target — even a few percent packet loss on the WAN will manifest as latency spikes for everything using the internet.
Frequently Asked Questions
- What causes sudden Wi-Fi latency spikes?
- The most common causes are: high channel utilization from congestion, a sticky client associated at low SNR, RF interference (often 2.4 GHz), WAN packet loss or congestion, or an AP firmware/hardware problem.
- What is a good latency for a Wi-Fi network?
- LAN latency (ping to your gateway) should be under 5ms on a healthy Wi-Fi network. Anything above 20ms on a local ping indicates a Wi-Fi or LAN problem. WAN latency depends on your ISP and location.
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