Radar Reflectivity – Live US Reflectivity Radar Map (dBZ)
Live radar reflectivity for the entire United States: the same NEXRAD Doppler radar picture forecasters use, with the dBZ scale explained below — what each color means, what reflectivity is for, and how the radar image is made.
What Radar Reflectivity Shows
The map above is the reflectivity layer — the radar picture most people mean when they say "the radar". Every colored pixel measures how much of the radar's pulse bounced back from something in the air: rain, snow, sleet, hail, and sometimes birds, insects, or hills. The stronger the return, the brighter and warmer the color. Green and blue mean light precipitation, yellow and orange mean moderate to heavy rain, and red, pink, and purple mark the most intense storm cores, where hail is likely. Where the map is blank, the radar sees no precipitation at all.
Reflectivity is one of the three base products of a pulsed Doppler radar, and it is the one the public knows best — the other two, velocity and spectrum width, describe wind motion and turbulence. This page shows the composite reflectivity mosaic for the whole United States, built from the National Weather Service NEXRAD network.
How to Read It: The dBZ Scale
Reflectivity is measured in dBZ — decibels of reflectivity (Z). The raw values span an enormous range, from tiny drizzle droplets to giant hailstones, so the logarithmic dBZ scale compresses them into a range of about -35 to +85 dBZ. The higher the number, the heavier the precipitation or the larger the particles. The scale below follows the National Oceanic and Atmospheric Administration's JetStream guide:
Two things to keep in mind. First, the radar does not measure rainfall directly — it measures returned power, and a rainfall rate is only estimated from it with a Z–R relationship. Hail inflates that estimate, because a water-coated hailstone reflects far more energy than the same amount of rain. Second, colors are a guide, not a verdict: a 55 dBZ core means a strong storm, but only a National Weather Service warning tells you it is officially dangerous. Always pair the map with the live warnings feed on this page.
What Reflectivity Is For
- Is it raining now? The fastest use of the map: green over your town means light rain, red means a downpour is overhead.
- Tracking storms: Animating the loop shows how fast a rain band or thunderstorm cell is moving and where it is headed next.
- Spotting hail and severe cores: Pink and purple cores above 60 dBZ are where large hail and damaging winds are most likely.
- Finding fronts and squall lines: Long narrow lines of yellow and red mark cold fronts and squall lines advancing across states.
- Winter weather: The same scale tracks snow bands and the rain–snow line during winter storms — snow usually shows lower dBZ than rain at the same rate.
- Planning around weather: Commutes, outdoor work, and events — check the loop, not just a single frame, to see whether rain is arriving or clearing.
How Reflectivity Is Made
The picture starts at more than 160 WSR-88D NEXRAD Doppler radar stations across the United States, jointly operated by the National Weather Service, the Department of Defense, and the Federal Aviation Administration. Each radar sends out pulses of microwave energy and listens for the echo. The strength of the returning energy at each point is the reflectivity, and modern dual-polarization radars send both horizontal and vertical pulses, which helps tell rain from hail, snow, and non-weather targets.
Two views come from the same scans. Base reflectivity is the lowest sweep, at a 0.5-degree elevation angle, and shows precipitation near the ground around one radar. Composite reflectivity takes the strongest echo at any height in a vertical column, so it shows the most intense part of a thunderstorm wherever it sits in the cloud. The National Weather Service stitches every station's scans into one national mosaic, refreshed every few minutes.
The live map on this page is that composite reflectivity mosaic, served through RainViewer's radar API as an animated 2-hour loop, with the official NOAA NEXRAD base reflectivity feed available in the layer selector (via Iowa State University's IEM service). The "Next 2 hours" view is different: it is simulated reflectivity from the NOAA HRRR weather model, a forecast rather than an observation.
What Reflectivity Can't Tell You
- Exact rainfall amounts: Radar estimates rain from reflectivity; only a rain gauge measures it. Hail makes the estimate run high.
- Rain versus snow, from color alone: Light rain and steady snow can share the same dBZ. Temperature and the forecast decide which it is.
- Weather behind the beam: The beam rises with distance and the Earth curves away, so far from a radar the beam can overshoot low rain — and hills can block it entirely.
- Rain that never lands: Virga — rain evaporating on the way down — lights up the radar while the ground stays dry.
- False echoes: The bright band of melting snow, ground clutter, and anomalous propagation can all paint colors where there is no weather. A lone bright patch on a clear day is usually one of these, not rain.
For the full beginner's guide to reading a radar map — velocity colors, loop controls, and common storm patterns — see How to Read Doppler Radar. For the animated national loop, open the National Radar Loop. To read this map as how hard it is raining, open the Rain Rate Radar page.
Radar Reflectivity FAQ
About This Page
Published: 10 November 2026 • Updated: 10 November 2026. Sources: NOAA JetStream — Radar Images: Reflectivity (noaa.gov/jetstream/reflectivity); National Weather Service — NEXRAD radar (radar.weather.gov); RainViewer radar API; Iowa State University IEM NEXRAD tile service. Radar data updates every 5 to 10 minutes; the "Next 2 hours" view is a NOAA HRRR forecast, not observed radar.