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Balcony | Ten minutes before the rain, something reminds you

A message before you leave on whether today suits drying, and a warning when the afternoon turns.
October 9, 2025 by
Balcony | Ten minutes before the rain, something reminds you
渥屋科技股份有限公司, 系統管理者
Balcony

SMART HOME BUTLER · BALCONY

Ten minutes before the rain, something reminds you

A message before you leave in the morning telling you whether today suits drying, and a warning when the afternoon turns — early enough to call home even if you are out.

08:00
told before you leave whether to hang out
10 min
of warning before the rain
2
questions: will it rain, is it dry

Drying laundry is really a timing problem

Subtropical weather turns without notice. The sun is perfect when you leave in the morning, a thunderstorm arrives at two, and by the time you get home at six the whole line has been soaked again and picked up dust with it.

The opposite failure is just as common: everything dried hours ago but nobody brought it in, so it hangs for another two days while night dew and daytime ultraviolet take turns at it.

Neither is difficult — both just need something to keep watching the forecast and the humidity. Which is exactly what a system is good at: it does not forget, and it does not need to be home.

early warning 100% 60% 50% 0% rain probability laundry dryness alert: rain coming 08:00 11:00 14:00 17:00 20:00 The alert fires when the blue line crosses 60%. The laundry is not fully dry yet, but rain is on the way
Two lines from the same day. What the system is looking for is the crossing point — blue climbing while green has not yet topped out.

It speaks twice in a day

  1. 08:00

    Does today suit drying?

    Three inputs: today's rain probability, the outdoor humidity, and the air quality. All three have to pass before it says yes. Hanging laundry out on a bad air day is a way of moving particles into your wardrobe.

  2. Afternoon

    Rain is coming

    An alert once the probability passes 60%. There is usually still time before it actually rains, so even from the office you can call home and ask someone to bring it in.

  3. Evening

    Dry, bring it in

    With balcony humidity back to normal and enough hours elapsed, you get a reminder that the laundry should be ready — so it does not hang out overnight collecting dew.

  4. With a powered airer

    It brings it in for you

    Not just a reminder. As the rain probability climbs, the airer retracts under the eave or lifts out of the way. That is the ideal case, but the first three stages work perfectly well without it.

The morning message is the most useful of them. Most people are not bad at bringing laundry in — they simply made the wrong call at breakfast. One message before you leave saves the entire day.

Four things it takes care of

No re-washing

Rained-on laundry usually needs another cycle. Avoiding that a few times adds up in water, power and time.

No wasted days

On days when the air is bad or the humidity too high, hanging things out makes them worse. The system just tells you not to.

You can act from anywhere

That is the point of the early warning. A message means you can ask someone at home, rather than discovering it when you get back.

Clothes last longer

Brought in when they should be, they avoid alternating night dew and prolonged sun. Dark colours in particular fade far more slowly.

The thresholds are adjustable

Your situationWarn to bring inDo not hang outNotes
Typical homeRain 60%Rain 40% or humidity 80%The general case
Balcony with an eaveRain 75%Rain 60%Light rain does not reach, so the thresholds can relax
Fully exposedRain 45%Rain 30%No buffer at all, so be conservative
On a main roadAs abovePlus PM2.5 above 50Weight air quality more heavily — fabric absorbs it
Rainy seasonRain 50%Humidity 85%Humidity stays high all season and nothing will dry anyway

What you need to have

What it doesCategory in the systemEssential?
Know whether it will rainweather integrationYes
Receive alertsnotify (phone app)Yes
Measure balcony humiditysensorRecommended
Measure air qualitysensorNice to have
Powered clothes airercover or switchIdeal if present
The weather integration is off by default; just add one at installation. Home Assistant includes a free weather source with no hardware to buy and no API key to apply for — you simply add it in settings. It is the only prerequisite for the whole setup.
Powered airers usually behave like curtains. A lifting airer is classed as a cover, the same category as blinds. If it only has up and down, wrap it with the woow_cover_entity component and it can stop at intermediate positions.

How the whole thing works

Rain probability Balcony humidity Air quality entity_state_trigger_notify schedule and push 08:00 — does today suit drying Afternoon — rain coming, bring it in Evening — dry, ready to collect
Three inputs, three moments. What this setup produces is mostly messages rather than actions, so it works fully without any powered equipment.

Use the ready-made blueprints

The hub ships with 22 tested automation blueprints — think of one as a fill-in-the-blanks form. This mostly uses entity_state_trigger_notify, with adascene_single firing the fixed-time morning recommendation.

FieldWhat it meansSuggested
Which numbersRain probability, balcony humidity, PM2.5—
Morning message timeBefore you leave08:00
Bring-in thresholdRain probability above60%
Message contentInclude the current readingsprobability and humidity
Active only whenThere is laundry outSee the note below
A "laundry is out today" switch matters. Without it you get bring-it-in alerts on every wet day whether or not anything is hanging, and within two weeks you will disable the lot. Flip it on when the morning message says today is suitable, and off once you have collected everything.

Just say the word

The WOOWTECH hub ships with HA-MCP, which lets AI connect straight into your system, build the rules, and then check for itself that they really fire. All you have to do is describe the outcome you want.

YouTell me at eight each morning whether today suits drying laundry. If I have things out, warn me before it rains.
pi agentYou had no weather source, so I added a free built-in one. The balcony has humidity and air quality sensors, which I can use in the decision. Three rules are built, plus a "laundry is out today" switch so you are not bothered on days when nothing is hanging. I simulated a rising rain probability and the alert reached your phone.
YouI will forget to turn that switch off
pi agentThen I will switch it off automatically at 11pm. At worst you get one extra day of reminders rather than permanent false alarms. Added.

Prompts you can copy straight across

Every block below can be copied whole with the button on the right. Pick the one closest to what you want — you do not need all five.

The simplest versionuse this if you just want it running
Check whether my system has a weather source. If it does not, add a
free built-in one that needs no API key. Then build a single rule:
when today's rain probability goes above 60%, push me a notification
to bring the laundry in, with the current figure in the message.
Just that one rule for now.
The full versionmorning advice, rain warning and dry alert in one go
Build the balcony laundry reminders properly, as three separate rules
rather than one. First create a switch called "laundry out today" and
have it turn itself off at 11pm every night. Rule one is the morning
advice at 8am: if rain probability, balcony humidity and PM2.5 all
pass, tell me today suits drying; if not, say which one failed.
Rule two is the bring-it-in alert: while the switch is on and rain
probability passes 60%, tell me to fetch the washing, with the current
figure in the message and at most two alerts a day. Rule three says it
should be dry once humidity is back to normal and four hours have
passed. If there is a powered airer, pull it under cover when the
probability climbs. Use the ready-made blueprints on the hub rather
than writing your own. When it is built, test it yourself, confirm it
really fires, and tell me which devices you used.
Tuned to your homefor a balcony with no cover at all
Our balcony is completely open with no cover, so even light rain
reaches the washing. Keep the thresholds cautious: warn me above 45%
rain probability, and advise against drying at all above 30% in the
morning message. We are on a main road too, so treat PM2.5 above 50
as a bad drying day as well. Leave everything else as it is.
Changing it lateradjust a number in one sentence
Too many false alarms. Move the bring-it-in threshold from 60% to 70%,
and shift the morning message to 7:30 because I leave early. Do not
touch the dry reminder at all. Tell me the conditions on all three
rules once you have changed them.
When something goes wrongnothing has ever arrived, so check layer by layer
I have never once received this bring-it-in reminder. Not a single time.
There are three places it could be breaking, so work down them in order.
Top layer is the weather source: is it reporting a rain number right now
at all? Middle layer is the rule itself: are the conditions written the
way I asked, and is it even switched on? Bottom layer is my phone: push
a plain test message and see whether this handset gets anything.
Stop at whichever layer is broken and tell me there. No guessing below it.
One caution: the HA-MCP connection URL is the key to your home. Do not post it publicly, and do not give it to services you do not trust.

Common questions

Is the forecast reliable?
Short-range rain probability is quite reliable, particularly one to two hours ahead — and that is exactly what this uses, rather than a multi-day outlook. Even when it is wrong, the cost is one unnecessary trip to the balcony.
Why is the switch necessary?
Because the system has no way to know whether anything is hanging. Without it you would get a bring-it-in alert on every wet day, which soon becomes noise. With automatic switch-off, the upkeep is essentially zero.
How does it know the laundry is dry?
From balcony humidity plus elapsed hours, not by measuring the clothes. Humidity back to normal means the environment is dry, and four hours or more usually does it. An estimate rather than a measurement, but a workable one.
Is bad air really a reason not to hang laundry?
Fabric absorbs airborne particles, cotton especially. A full day out on a bad day carries the outside into your wardrobe. If you must, giving everything a shake before bringing it in helps.
Can I do this without balcony sensors?
Yes — the forecast alone produces the two most important messages. Humidity and air quality are refinements that sharpen the decision, and adding them later needs no rebuild.
Do I have to rebuild to change a threshold?
No. Just say "too many false alarms, warn me at 70% instead" and the assistant will find that rule and edit it.
dry and clean

After one rainy season

It has been a long time since you came home to a line of soaked washing, and the "I should never have hung that out" feeling has gone with it.

All from a single message at eight in the morning.

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