UV Index card

Who it’s for

Public health managers, outdoor venue operators, and school safety coordinators ask “is the UV level safe for outdoor activity right now, or should we issue a sun-protection advisory?” They need a single color-coded value that translates the UV index scale into an immediate action signal.

What it does

A sensor reading 6 shows an orange icon and value — High — so a stadium safety officer knows sun-protection measures are recommended for anyone spending extended time outdoors. The same card shows green at 1 — Low — and red at 11 — Extreme.

• Color-coded icon and value across five UV bands from Low to Extreme, matching the WHO international UV index scale
• Last-updated timestamp showing how long ago the reading arrived
• Shows one sensor’s data; it does not chart UV trends or compare multiple sensors

How to set up

Data keys

Key	Role	Type	Description
uv	Main value	Timeseries	UV index (dimensionless scale 0–11+); change the key name to match your device’s telemetry key

The widget ships with a simulated function datasource key labeled UV Index, 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.

The card shows the value with no decimal places. If the key has never reported, the card displays the label and icon with an empty value, not an error.

Value ranges

Range	Level	Color
0–2	Low	Green
2–5	Moderate	Orange
5–7	High	Orange
7–10	Very High	Red-Orange
10+	Extreme	Red

How to customize

• To use your own UV thresholds — edit Icon color ranges and Value color ranges; set the same boundaries in both so the icon and the number always agree. The WHO standard bands (0–2/2–5/5–7/7–10/10+) are the recognized defaults.
• To change the icon — set Icon to any Material or MDI icon name.
• To hide the label, icon, or timestamp — turn off Show label, Show icon, or Show date.
• To switch to an absolute timestamp — turn off Last update ago in the date format settings.
• To match your dashboard’s fonts — set Value font and Label font.

Tips

• Keep Icon color ranges and Value color ranges on the same boundaries so the icon and the number always show the same band.
• The WHO recommendation for sun protection starts at UV index 3 (Moderate) — if your audience needs a simpler trigger, lower the High threshold accordingly.
• Pair this card with a solar radiation card: UV index and irradiance peak together at solar noon, but cloud cover can scatter UV more than visible light, so UV index occasionally remains elevated under thin overcast even when irradiance drops.