Slow internet in the evening: causes and fixes

Updated 23 September 2026

A connection that is fast by day and sluggish at night is a classic symptom. Three very different causes can explain it, and two measurements tell them apart.

The test that separates the three causes

Run two sets of measurements, over an Ethernet cable, with nothing else running:

one in the morning or early afternoon;
one between 8pm and 10pm.

Result	Likely cause
Good speed at both times	The problem is Wi-Fi or a device
Speed drops in the evening, over a cable	Provider network congestion
Speed fine but ping soars in the evening	A saturated link, or household usage

Write the numbers down: they will be useful if you have to call your provider.

Cause 1: the provider's network is busy

Between 7pm and 11pm everyone streams at once. The consequence depends on the technology:

Coaxial cable: bandwidth is shared between subscribers in the same area. It is the technology most prone to evening slowdowns.
4G / 5G at home: the mast is shared between all its users, and speed can fall fivefold at peak times.
Fibre to the home: far steadier, though congestion further up the network remains possible.
ADSL / VDSL: the line's speed does not change, but exchange equipment can be loaded.

What you can do: report the problem with your timestamped measurements. A provider that confirms congestion in your area can upgrade its equipment, but that takes time. If it is structural and fibre is available where you live, that is the real cure.

Cause 2: the building's Wi-Fi is crowded

In the evening every neighbouring router is transmitting. On the 2.4 GHz band, dozens of networks share three non-overlapping channels.

What you can do:

move your devices to the 5 GHz band, which is far less crowded;
restart the router early in the evening, which re-runs automatic channel selection;
manually pick channel 1, 6 or 11 on 2.4 GHz if you must stay there;
wire the TV and the console, which consume the most.

Cause 3: your own household

A console downloading an 80 GB update, an online backup, a 4K TV and three phones: in the evening everything fires at once.

What you can do:

schedule console and computer updates overnight;
cap the speed of backup tools;
turn on the router's QoS to prioritise calls or gaming;
make sure no neighbour is on your Wi-Fi: change the password to WPA2 or WPA3 if in doubt.

The special case of latency

If speed stays fine but everything feels slow, look at the ping. Latency going from 15 ms to several hundred milliseconds while speed holds points to a saturated link, usually the upload. The culprit is often a backup or a file transfer, not your provider.

When to call the provider

Call if, over a cable with nothing else running, your evening speed is less than half your daytime speed on several consecutive days. Present your measurements with dates, times and connection type. Ask explicitly whether your area is flagged as congested and whether an upgrade is planned.

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Frequently asked questions

Why does my speed only drop between 8pm and 10pm?

That is peak usage: a busier provider network, more active neighbouring Wi-Fi and simultaneous household use. Cabled measurements at two times of day show which one dominates.

Will switching provider fix evening congestion?

Sometimes, if the new provider uses a different technology, for example fibre instead of cable. On the same shared infrastructure, the problem is likely to return.

Is restarting the router every evening a good idea?

It can help by re-running Wi-Fi channel selection and freeing memory. Needing it daily is a sign of a hardware fault or congestion worth reporting.