Simple temperature chart card

Who it’s for

Building managers, city planners, and environmental monitoring teams ask “how has temperature changed over time, without the clutter of delta comparisons?” They want to see the current reading and a trend line in one card, nothing more.

What it does

A sensor currently reading 22°C shows an orange value — Warm — above a chart that reveals whether temperature has been climbing through the morning or cooling toward evening.

• Large current temperature value color-coded across seven bands from Extreme Cold to Extreme Heat
• Time-series chart of temperature readings over the selected time window, averaged per interval
• Shows one sensor’s data; it does not compare multiple probes or show period-over-period deltas

How to set up

Data keys

Key	Role	Type	Description
temperature	Chart series	Timeseries	Temperature in °C; 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 Temperature, 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 (°C)	Level	Color
below −20	Extreme Cold	Deep Blue
−20 – 0	Cold	Blue
0 – 10	Cool	Light Blue
10 – 20	Moderate	Orange
20 – 30	Warm	Orange
30 – 40	Hot	Red-Orange
above 40	Extreme Heat	Red

How to customize

• To use your own temperature thresholds — edit the color ranges on the Latest data key; adjust the seven default bands to match your operational or comfort requirements.
• To display in °F — add a unit conversion function to the data key; adjust the range boundaries to Fahrenheit equivalents.
• 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 diurnal temperature pattern or a trend over several days matters more than the exact period-over-period delta. Add the full temperature chart card if you need a delta °C figure alongside the chart.
• A visible overnight low followed by a rising morning curve is the normal outdoor signature; a flat or rising overnight line may indicate an urban heat island effect or a sensor inside a poorly ventilated enclosure.
• Pair with a humidity simple chart card to see whether humidity drops as temperature rises — the inverse correlation is the outdoor pattern; humidity rising with temperature may indicate rain approaching.