Simple visibility chart card

Who it’s for

Road safety managers, airport operations teams, and port and harbor controllers ask “how has visibility changed over the day, without the clutter of delta comparisons?” They want to see the current reading and the daily curve in one card, nothing more.

What it does

A sensor currently reading 2.5 km shows an orange value — Moderate — above a chart that reveals the visibility pattern over the selected time window: high and stable through the day, dropping sharply in the late evening as fog forms, then slowly recovering toward dawn.

• Large current visibility value color-coded across three bands from Poor to Good
• Time-series chart of visibility readings over the selected time window, averaged per interval
• Shows one sensor’s data; it does not compare multiple sensors or show period-over-period deltas

How to set up

Data keys

Key	Role	Type	Description
visibility	Chart series	Timeseries	Atmospheric visibility distance (km); drives the chart. The Latest value overlay is automatically derived from this same key
Latest	Latest value	Timeseries	The headline figure above the chart. Its own color ranges are where the band colors are edited

The widget ships with a simulated function datasource key labeled Visibility, so it draws random values until you point the datasource at a device and rename the key.

To point it at your own device: open the dashboard in edit mode, open the widget’s Datasources, pick the entity or entity alias, and replace the function key with the key your device reports.

If the key has never reported for the selected time window, the chart is empty and the value overlay shows no data.

Value ranges

Range (km)	Level	Color
0–1	Poor	Red
1–4	Moderate	Orange
4+	Good	Green

How to customize

• To use your own visibility thresholds — edit the color ranges on the Latest data key; adjust the three default bands to match your operational or regulatory thresholds.
• To hide or show the chart — toggle Show chart in the widget settings.
• To change the chart line color — set Chart color.
• To hide the entity name subtitle or the timestamp — turn off Show subtitle or Show date.
• To match your dashboard’s fonts — set the font options under each data key’s appearance settings.

Tips

• Use this card when the daily visibility curve matters more than the exact period-over-period change. Add the full visibility chart card if you need a delta km figure alongside the chart.
• Poor visibility below 1 km corresponds to the ICAO threshold for low-visibility procedures at airports and is the common trigger for reduced speed limits on motorways during fog events; adjust the Poor/Moderate boundary to match your local regulation.
• Fog typically forms when visibility drops quickly overnight while relative humidity approaches 100% — pair with a simple humidity chart card to correlate the two signals and distinguish radiation fog from advection fog.