How to Read Weather Radar: What the Colors Actually Mean

Weather radar looks intimidating — a blob of shifting colors creeping across the map — but it answers one simple question: where is precipitation falling right now, and how hard? Once you know what the colors stand for, a radar loop becomes one of the most useful tools in weather.

You can follow along with live, animated radar on the LEV live map by switching on the Precip Radar layer and pressing play.

The colors are a measure of intensity

Radar works by firing out a pulse of microwave energy and listening for the echo that bounces back off raindrops, snowflakes and hailstones. Bigger and denser particles reflect more energy. That returned energy is plotted as reflectivity, and reflectivity is what the colors represent.

The rough rule of thumb:

• Light green — drizzle and light rain. You might not even need an umbrella.
• Dark green to yellow — steady, moderate rain.
• Orange — heavy rain. Roads start to pool.
• Red — very heavy rain, often a thunderstorm core.
• Magenta / purple / white — extreme returns. This usually means large hail or a violent storm, not just rain.

The dBZ scale, briefly

Behind the colors is a number called dBZ (decibels of reflectivity). You don't need the math — just the intuition that higher numbers mean heavier precipitation:

• 5–20 dBZ — light rain or snow
• 20–40 dBZ — moderate rain
• 40–50 dBZ — heavy rain, a strong thunderstorm
• 50+ dBZ — torrential rain or hail

When a forecaster says a storm has a "60 dBZ core," they mean its center is reflecting an enormous amount of energy — a sign of hail or a serious downpour.

Reading the motion, not just the picture

A single radar frame tells you where rain is. A radar loop — several frames played in sequence — tells you where it is going. That's the real skill:

• Direction — watch which way the blobs drift to know if a storm is heading toward you.
• Growth — colors brightening from green to red in place mean a storm is intensifying.
• Lines — a long arc of yellows and reds is often a squall line, which can bring sudden wind.

This is also where weather and the wider world meet. On LEV you can overlay radar with live flight paths to see why planes are diverting around a storm, or with shipping lanes to spot ports in the path of bad weather — the kind of fusion view a radar-only app can't show.

Common traps

Radar is powerful but not literal. A few things routinely fool people:

• Empty radar during real rain. The beam rises with distance as the Earth curves away, so far from a radar site it can sail right over low clouds. See the FAQ below.
• "Ghost" echoes. Birds, insects, dust and even tall buildings can return faint echoes that aren't precipitation.
• The bright band. A ring of stronger returns can appear where snow melts into rain aloft — it looks heavier than what reaches the ground.

Put it into practice

The fastest way to learn radar is to watch it move. Open the live radar layer, press play on the time bar, and follow a system for a few minutes. Pair it with our guide to GeoColor satellite imagery to see the clouds feeding those storms, or jump to the Atlantic hurricane tracker when the season is active.