Internet dropouts ยท symptom
The internet drops out when it rains
Weather is the most useful clue you can bring to a fault report, because it points at a physical cause and physical causes get fixed. What rain actually does to your connection depends entirely on which technology you are on, and for one of the five it should do nothing at all.
Last reviewed: 15 August 2026 · by Alien IT Solutions
Which connection type are you on?
Weather is the most useful clue you can bring to a fault report, because it points at a physical cause and physical causes get fixed. What rain actually does to your connection depends entirely on which technology you are on, and for one of the five it should do nothing at all.
The answer to this symptom is genuinely different on each of the five nbn technologies, because the physical thing that fails is different. All five are written out below. Jump to yours, or read the lot.
Jump to your connection type
Not sure which one you have?
Look at the box your router plugs into. A separate nbn box with Power, Optical and Alarm lights means fibre to the premises. Four lights reading Power, Downstream, Upstream and Online means HFC. Blue lights on a small unit means fibre to the curb. An antenna on the roof means fixed wireless. And if there is no nbn box at all, only a modem from your provider plugged into a phone socket, you are on fibre to the node.
The light decoder walks you through it, or read the longer explanation of the connection types.
FTTP: Fibre to the Premises
Probably not the fibre.
Fibre carries light down a glass strand. It does not corrode, it does not short out, and rain does not get into it the way water gets into a copper pair. If your FTTP service drops when it rains, the fibre itself is the least likely explanation on this list, and chasing it will waste your time.
What actually correlates with rain on an FTTP service is power. Storms bring brownouts and brief cuts, and both your nbn connection box and your router need mains power to work. A dip too short to stop your lights will happily reboot a router. The other real possibility is water in the conduit at the point the fibre enters your property, or damage to the box outside, both of which belong to nbn and neither of which you should go and inspect.
What to try yourself
- Watch the Optical light on your nbn connection box during a dropout. Red means the box lost the nbn network, which is a genuine network fault worth reporting. If Optical stays green while the internet is out, the fibre held and the fault is after it, in your router or your provider.
- Check whether the Power light on the connection box has restarted, and whether your router's uptime has reset. If either rebooted, you had a power event, not a fibre event.
- Plug the router into a different outlet, ideally on a different circuit, and consider a small UPS if storms are routine where you live.
- Write down the date and time of every dropout and how long it lasted, for at least three days. A list of timestamps is the difference between a fault your provider can escalate to nbn and a phone call that ends in try restarting your router.
What to say to your provider
Say: I am on FTTP. My service drops during rain and the Optical light on the nbn connection box goes red when it happens.
That sentence does two things at once. It rules out the Wi-Fi questions, and it hands them a network side symptom on nbn equipment.
FTTN: Fibre to the Node, and Fibre to the Building
This is the classic FTTN fault, and it is real.
On FTTN the last stretch to your house is the old copper telephone pair, and it runs through joints, pits and a lead-in that were often put in decades ago. Water gets into all of them. Wet copper changes its electrical properties, the noise on the line rises, and your modem either loses synchronisation outright or drops its speed to stay connected.
The giveaway is the timing. A water ingress fault usually gets worse during rain and stays bad for a day or two afterwards, then improves as things dry. That lag is what separates it from everything else, and it is the detail that makes a provider take you seriously.
What to try yourself
- Note whether the fault continues after the rain stops, and for how long. A day or two of bad service after a wet night is close to a signature for water in the copper.
- Look at the DSL, Broadband or Line light on your modem when it happens. If it drops out and re-synchronises, that is a line event and worth recording each time.
- If your modem has a status page, write down the sync speed and the noise margin on a dry day and again on a wet one. A margin that collapses in the wet is strong evidence.
- Write down the date and time of every dropout and how long it lasted, for at least three days. A list of timestamps is the difference between a fault your provider can escalate to nbn and a phone call that ends in try restarting your router.
What to say to your provider
Say: I am on FTTN. I have an intermittent fault that correlates with rainfall and continues for a day or two afterwards. I have dates and times. Please raise a fault with nbn and ask for the copper to be tested for water ingress in the pit and the lead-in.
Naming water ingress matters. It is a category of fault nbn technicians recognise and test for, and it survives the retest that closes vaguer reports.
If they tell you the line tests fine right now, ask them to note that the fault is weather dependent and to test again while it is wet.
FTTC: Fibre to the Curb
Possible, but there is much less copper to get wet.
FTTC runs fibre to a small unit in a pit at your kerb and uses copper only for the last few metres. That short run means far fewer joints for water to find than on FTTN, so a rain related fault here is less likely, but it is not impossible.
Both candidates are nbn's to inspect rather than yours: the pit at the kerb, which can flood, and the lead-in running from the kerb to your wall. There is also a quirk worth knowing: the kerbside unit on FTTC is powered from inside your house, down the same copper. If your power flickers in a storm, the unit at the kerb loses power too, and the outage will look like a line fault.
What to try yourself
- Watch the Connection light on the nbn connection device during a dropout. Solid red, or red blinking, is a line fault and nbn's guide says to switch the device off and call your provider.
- Check whether your mains power flickered at the same moment. Because the kerbside unit is powered from your premises, a brief cut at your place takes the kerb unit down with it.
- Confirm the phone cable from the device to the wall socket is properly seated. You should hear it click.
- Write down the date and time of every dropout and how long it lasted, for at least three days. A list of timestamps is the difference between a fault your provider can escalate to nbn and a phone call that ends in try restarting your router.
What to say to your provider
Say: I am on FTTC. The service drops during wet weather and the Connection light on the nbn connection device goes red. Please raise a fault with nbn and ask them to check the DPU in the pit and the lead-in for water.
Mentioning the DPU by name signals you know the kerbside unit exists, which shortens the call.
HFC: Hybrid Fibre Coaxial
Worth chasing. Water and coaxial cable do not mix.
HFC uses the coaxial cable that used to carry cable television. Coax is more robust than a telephone pair, but its weak point is the connectors, especially any outdoors. Once water gets past a connector the shield corrodes, noise gets in, and the connection starts erroring and dropping. Rain makes it worse, drying improves it, and over months it gets worse overall as the corrosion advances.
The other rain related cause on HFC is the shared street equipment, including amplifiers, which can suffer water ingress and take out a whole run of houses at once.
What to try yourself
- Ask a neighbour on the same cable service whether they see it too. HFC is shared down your street, so a whole street failing in the wet points squarely at the street equipment.
- Look at the four lights on the nbn connection box during a dropout. If Downstream or Upstream stops being solid green, the cable side is dropping rather than your router.
- Look at where the coax enters your house for green or white corrosion around the connector, and for cracked or perished outer sheath. Look only. Do not start unscrewing outdoor connectors.
- Write down the date and time of every dropout and how long it lasted, for at least three days. A list of timestamps is the difference between a fault your provider can escalate to nbn and a phone call that ends in try restarting your router.
What to say to your provider
Say: I am on HFC. The service degrades in wet weather. Please raise a fault with nbn and ask them to check for water ingress on the coaxial connectors and the street amplifier.
If neighbours are affected too, say so immediately. A multi premises fault is prioritised differently from a single one and is far harder to close as no fault found.
Fixed Wireless: nbn Fixed Wireless
Expected to some degree, and nbn documents it.
Fixed wireless sends your data through the air between an antenna on your roof and an nbn tower, so weather is genuinely in the path. Heavy rain absorbs and scatters the signal, which is known as rain fade, and the effect is worse the further you are from the tower.
nbn's own fixed wireless troubleshooting guide states that certain weather events, particularly in the summer seasons, can cause a degradation in cell performance, and that it uses mitigation techniques to reduce the impact. So a service that dips in a heavy storm and recovers afterwards is behaving as the technology is documented to behave. What is not normal is a service that degrades in light rain, or that never fully recovers once the weather clears.
What to try yourself
- Separate heavy storms from light rain. Dropping out in a downpour is expected. Dropping out in drizzle suggests your link already has very little margin, which is a fault worth reporting.
- Check whether the service fully recovers once the weather clears. A link that stays degraded afterwards points at something that moved or degraded rather than at the rain.
- Watch the Outdoor Unit and Status lights on the nbn connection box for about 60 seconds, which is nbn's own instruction, and note whether they are steady or cycling.
- Think about whether anything has grown or been built in the line of sight to the tower since installation. Trees are the usual answer, and they get worse when wet and heavy.
- Write down the date and time of every dropout and how long it lasted, for at least three days. A list of timestamps is the difference between a fault your provider can escalate to nbn and a phone call that ends in try restarting your router.
What to say to your provider
Say: I am on fixed wireless. My service degrades in light rain and does not fully recover afterwards. Please raise a fault and ask nbn to check my signal levels and whether the line of sight to the tower is still clear.
Do not accept it is the weather as a closing answer if the problem happens in light rain or persists after it dries. Ask them to state your current signal level and compare it to what it was at installation.
On this connection type
- Do not go up to the antenna, and do not let anyone talk you into adjusting it. nbn's guide specifically says to contact your provider if the outdoor unit is more than 2 metres off the ground. Aligning that antenna is a job for someone with the right equipment and insurance.
Then, whatever they tell you
Providers work from a script, and the script assumes you have not checked anything. Say this early and you skip most of it.
- Ask them to raise a fault with nbn, and ask for the fault reference number. A fault that was never raised cannot be tracked, and this is where most calls quietly end.
- Ask what the line is actually doing at their end right now, and whether they can see dropouts in their own logs. They usually can.
- If they close it without fixing it, ask for the complaint to be escalated internally, and get the complaint reference in writing.
If it stays broken and they stop being useful, the Telecommunications Industry Ombudsman is free for you to use, and providers do respond to it. Here is how that works.
Before you touch anything
- Do not go up a ladder or onto a roof. That includes fixed wireless antennas and dishes. nbn's own fixed wireless guide tells you to contact your provider rather than touch an outdoor unit mounted more than 2 metres off the ground. There is nothing you can fix up there that is worth a fall.
- Do not open the nbn connection box, and do not touch the pit or the lead-in cable. That equipment belongs to nbn, not to you or your provider. Fibre terminations carry laser light that you cannot see and should not look into. Opening it can also end your service and leave you liable for the repair.
- Leave the backup battery alone beyond what your provider's own script tells you. If you have the optional Power Supply with Battery Backup, follow your provider's instructions for it and nothing more.
- Burning smell, scorch marks, or a modem too hot to touch: stop. Switch it off at the wall, unplug it, and do not plug it back in. Tell your provider it needs replacing. There is no troubleshooting step that comes before this.
Where this comes from
Every light state and every figure on this page comes from the sources below, each checked on 15 August 2026. Where a provider's guide disagrees with nbn's, the provider is describing their own hardware and you should follow theirs.
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