Solar radiation chart card

Who it’s for

Solar farm operators, agricultural irrigation planners, and environmental monitoring teams ask “how has solar irradiance changed over the selected period, and how does today’s yield potential compare to the same period last week?” They want the current reading, the trend shape, and the period-over-period delta in one card.

What it does

A sensor averaging 380 W/m² this week versus 180 W/m² last week shows an orange value — Moderate — with a +111% delta and a +200 W/m² absolute change, plus a chart of readings over the selected window.

• Large current solar-radiation value color-coded across five bands from None to Very High
• Delta percentage and absolute delta comparing the current period to the previous one
• Time-series chart of solar-radiation readings averaged per interval
• Shows one sensor’s data; it does not compare multiple pyranometers

How to set up

Data keys

Key	Role	Type	Description
radiation	Chart series	Timeseries	Solar irradiance in W/m²; drives the chart and all derived overlays
Latest	Latest value	Timeseries	The headline figure above the chart. Its own color ranges are where the band colors are edited
Delta percent	Percentage change	Timeseries	Change against the previous period, as a percentage
Delta absolute	Absolute change	Timeseries	Change against the previous period, in the key’s own unit

The widget ships with a simulated function datasource key labeled Solar Radiation, 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 all overlays show no data.

Value ranges

Range (W/m²)	Level	Color
0	None	Blue
0–250	Low	Green
250–500	Moderate	Orange
500–1000	High	Orange
1000+	Very High	Red

How to customize

• To use your own irradiance thresholds — edit the color ranges on the Latest data key; adjust the five default bands to match your site’s conditions.
• To change the comparison period — adjust the Time window on the dashboard; the delta automatically compares to the equivalent preceding period.
• 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

• A large positive delta week-over-week in spring confirms that seasonal irradiance gain is tracking as expected for yield forecasting; a large negative delta mid-summer often indicates cloud cover or soiling on the sensor or panels.
• The chart’s bell-curve shape on a clear day (low at dawn, peaking at solar noon, low at dusk) is a useful sanity check that the pyranometer is oriented correctly and unobstructed.
• Pair this card with a temperature chart card: high irradiance with high temperature reduces panel efficiency (the power temperature coefficient), so the combination explains underperformance even on sunny days.