How much water a park needs depends on the weather. On a hot, windy day the soil dries fast; on a rainy day no watering is needed. A fixed schedule does not see that difference. Weather-based irrigation sees it and changes the duration accordingly.
What is weather-based irrigation?
It is making the irrigation decision from weather data. Three inputs are used:
| Input | What it says | Effect on the decision |
|---|---|---|
| Hourly forecast | Temperature, wind, rain probability and amount | Postpones if rain is expected; waits above the wind limit; shortens on a cool day |
| Last 24 h rainfall | Rain that fell, in mm | Deducted from the daily water demand |
| Rain sensor | Is it raining right now | Stops watering at once; confirms the forecast |
The forecast and recent rainfall come from the cloud; the sensor from the field. The AI combines the three with satellite data and the water-demand calculation. All data sources: which data does the AI look at?
It won't water if rain is coming
The system follows the site's hourly forecast. If rain is expected in the hours ahead, it postpones the scheduled watering. No water is wasted right before rain. Light rain does not cut the water entirely; the missing part is topped up.
It sees the real rainfall too
Forecasts are not always right; the expected rain does not come, or a shower arrives unannounced. The rain sensor on site reports the real rainfall. Watering stops at that moment; the decision moves to the next day. The sensor is the field confirmation of the forecast.
Where is the rain sensor mounted?
- In the open. Not under a tree, an eave or against a wall; rain must fall on the sensor.
- Outside sprinkler range. If irrigation water reaches the sensor, the system thinks it is raining and stops.
- At a reachable height. It must be accessible for cleaning and testing; a post or the top of a box works.
- Near the controller. The sensor connects to the valve controller; keep the cable short. Its value shows in the panel.
How is the rain sensor tested?
- Open one line for a few minutes from the panel or over Bluetooth.
- Drip water onto the sensor.
- The line should stop shortly; the panel should show the rain state.
- Once the sensor dries, the line should open again.
Test at season start and whenever the sensor is cleaned. A sensor covered in leaves and dust reads wrongly. Installation notes: points to watch during installation.
How does it differ from the AI postponement?
A rain sensor knows one thing: is it raining now. The AI postponement knows tomorrow: rain probability, amount, wind and temperature. One stops watering; the other does not start it.
| Situation | Rain sensor only | AI + sensor |
|---|---|---|
| Showers expected tomorrow | Waters today | Postpones today |
| 10 mm fell yesterday, clear today | Full duration | Shortens or skips |
| Rain starts during watering | Stops | Stops |
| Wind 7 m/s | Waters, spray drifts | Waits |
| Cool spring day | Full duration | Shorter duration |
The sensor confirms the AI from the field; the AI sees the days the sensor cannot. The difference against a fixed schedule is in how water is saved.
What's in it for you?
- Water savings: no watering before rain, so not a drop goes to waste.
- Healthy plants: the soil stays neither too dry nor too wet, and roots get balanced moisture.
- Less energy and maintenance: pumps and valves that don't run needlessly last longer.
- Zero hassle: you don't have to watch the weather or change the schedule; the system does it for you.
On which sites is it essential?
The rain sensor is optional; the system works on the forecast alone. It is recommended in three cases: coastal and foothill sites with frequent local showers; rural sites far from a forecast station; medians where spray reaches a path or a road. A soil moisture sensor answers a different question: how much water is left in the soil. See irrigation with a soil moisture sensor. Satellite data: how often do satellites image your park?
Frequently asked
Without a rain sensor, does watering stop in the rain?
If the forecast expects rain, that day's watering is postponed anyway. In an unexpected shower with no sensor, watering continues; that is what is missing.
How often is the sensor replaced?
Rain sensors work for years; one cleaning a year is enough. The sensor value shows in the panel.
Does light rain cut watering entirely?
No. The rain that fell is deducted from the demand; the missing part is topped up. Other questions are on the FAQ page.