Rain Rate Radar – Live US Rain Rate Map (mm/h)

Live rain rate for the entire United States: how hard it is raining right now, in millimetres per hour and inches per hour — with the rain rate scale explained below, what each color means, what rain rate is for, and how radar turns reflectivity into a rainfall rate.

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Live US Rain Rate Radar Map (mm/h)

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🌧️ Rain Rate (mm/h)

0.3 2.7 12 36 100 400+ ❄️

Drizzle Light Heavy Extreme

Live US rain rate radar map – Real-time NOAA NEXRAD storm mosaic

🔮 Future radar — next 2 hours: Switch to “Next 2 hours” above the map to see where rain is expected next. This view is a NOAA HRRR weather-model forecast (simulated reflectivity, converted to an estimated rain rate the same way, new model run every hour via Iowa State University’s IEM service) — a forecast, not observed radar. It is most accurate for steady, organized rain in the first 30–60 minutes, and less reliable for fast-developing scattered thunderstorms. RainViewer’s free public radar API publishes past radar only, so the future view uses NOAA HRRR instead.

What Rain Rate Shows

The map above is the rain rate layer — the same live NEXRAD radar picture as the reflectivity map, read as how hard it is raining. Every colored pixel is an estimated rainfall intensity: green means a light drizzle that barely wets the ground, yellow and orange mean steady to heavy rain, and red, pink, and purple mark the most intense downpours, where flash flooding is possible. Where the map is blank, no rain is falling at all.

Rain rate is measured in millimetres per hour (mm/h) — and in inches per hour (in/h) on this page. A rate of 10 mm/h means that if the rain kept falling at the same intensity for a full hour, 10 millimetres of water would collect. A short burst at 50 mm/h looks dramatic, but it is the rate held over time that floods streets and rivers, not a single bright frame.

How to Read It: The Rain Rate Scale

Radar does not measure rainfall directly — it measures reflectivity, in dBZ, and converts it to a rain rate with the standard Marshall–Palmer Z–R relationship (Z = 200·R^1.6). The table below is that conversion, so you can read any color on the map as an estimated rain rate. The values are estimates: hail, snow, and different rain types all shift the real rate away from the table.

15 – 20 dBZ: 0.3 – 0.6 mm/h (0.01 – 0.02 in/h) — Drizzle, barely wets the ground

20 – 30 dBZ: 0.6 – 2.7 mm/h (0.02 – 0.11 in/h) — Light rain

30 – 40 dBZ: 2.7 – 11.5 mm/h (0.11 – 0.45 in/h) — Moderate rain

40 – 50 dBZ: 11.5 – 48.6 mm/h (0.45 – 1.91 in/h) — Heavy rain

50 – 55 dBZ: 48.6 – 100 mm/h (1.91 – 3.93 in/h) — Very heavy rain, flash-flood risk

55 – 60 dBZ: 100 – 205 mm/h (3.93 – 8.07 in/h) — Extreme downpour, severe storms

60+ dBZ: 205+ mm/h (8+ in/h) — Usually hail, not real rain: the rate is inflated

Two things to keep in mind. First, the map shows intensity now, not how much rain has fallen in total — a 15-minute burst at 40 mm/h adds only 10 mm to the ground. Second, colors are a guide, not a verdict: a red core means very heavy rain is likely, 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 Rain Rate Is For

How hard is it raining now? The fastest use of the map: green over your town means drizzle, red means a downpour is overhead.
Flash-flood risk: Rain falling faster than about 25 mm/h (1 in/h) can overwhelm drains and flood streets, especially if it keeps falling for an hour or more.
Driving safety: Heavy rain cuts visibility and raises the risk of hydroplaning — check the rate along your route, not just at home.
Outdoor work and events: A rate under 2.5 mm/h is usually workable outdoors; above 10 mm/h most outdoor plans need cover.
Comparing storms: Animating the loop shows whether a storm is strengthening or weakening, and where the heaviest rain is headed next.
Winter weather: Snow shows a lower equivalent rate than rain at the same dBZ, so a green band in a snowstorm can still mean steady snowfall — check the temperature with the map.

How Rain Rate 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, measured in dBZ.

Reflectivity is then converted to a rain rate with a Z–R relationship. The standard one, published by Marshall and Palmer in 1948, is Z = 200·R^1.6, where Z is the reflectivity factor and R is the rain rate in mm/h. The National Weather Service's MRMS system refines that estimate by blending radar with rain-gauge reports and weather-model data into quantitative precipitation estimates (QPE). This page reads the live composite reflectivity mosaic through the Marshall–Palmer scale, so every color is an estimated rain rate — the same method forecasters use to turn a radar picture into rainfall.

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, converted to an estimated rain rate the same way — a forecast rather than an observation.

What Rain Rate Can't Tell You

Exact rainfall amounts: Radar estimates rain from reflectivity; only a rain gauge measures it. Hail makes the estimate run high, sometimes by several times.
Rain versus snow, from color alone: Light rain and steady snow can share the same dBZ, and snow falls more slowly, so its true rate is lower than the table suggests.
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 see the same map in raw reflectivity, with the full NOAA dBZ scale, open the Radar Reflectivity (dBZ) page.

Rain Rate FAQ

Rain rate is how fast rain is falling right now, measured in millimetres per hour (mm/h) or inches per hour (in/h). A rate of 10 mm/h means that if the rain kept falling at the same intensity for a full hour, 10 millimetres of water would collect. The map on this page shows the live estimated rain rate across the United States, updated every 5 to 10 minutes.

Radar does not measure rainfall directly. The NEXRAD radar measures reflectivity — how much energy bounces back — and converts it to a rain rate with a Z–R relationship. The standard Marshall–Palmer relationship is Z = 200·R^1.6, where Z is the reflectivity factor and R is the rain rate in mm/h. The National Weather Service's MRMS system refines that estimate by combining radar with rain-gauge reports and weather models. On this page the live radar loop is read through that same scale, so each color is an estimated rain rate.

The bands most forecasters use are: light rain under 2.5 mm/h (under 0.1 in/h); moderate rain 2.5 to 10 mm/h (0.1 to 0.4 in/h); heavy rain 10 to 50 mm/h (0.4 to 2 in/h); and violent rain over 50 mm/h (over 2 in/h). Rain falling faster than about 25 mm/h (1 in/h) can overwhelm drains and start flash flooding on hard ground, especially if it keeps falling for an hour or more.

It is an estimate, good to about a factor of two in steady rain. It runs high when hail is mixed in, because hail reflects far more energy than the same amount of rain, and it runs low when the radar beam overshoots low rain far from the station or when the rain type differs from the standard drop-size assumption. Rain gauges are the only true measurement, which is why the National Weather Service blends gauge reports into its rainfall totals. Treat the map as how hard it is raining, not as an exact gauge reading.

Rain rate is intensity right now — how fast it is falling, in mm/h. Rain totals are accumulation — how much has fallen over a period, such as 1 hour or 24 hours. The total is the rate added up over time: steady rain at 10 mm/h for 3 hours gives a 30 mm total. A short burst at 50 mm/h looks dramatic on the rate map but may only add a few millimetres to the total.

Yes. The map animates the past 2 hours of observed radar, with new frames every 5 to 10 minutes, and the layer selector also offers the live NOAA NEXRAD feed. The 'Next 2 hours' view is different: it is a NOAA HRRR model forecast of simulated reflectivity, converted to an estimated rain rate the same way, and it is most accurate in the first 30 to 60 minutes.

About This Page

Published: 11 November 2026 • Updated: 11 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; Marshall & Palmer (1948) Z–R relationship. Radar data updates every 5 to 10 minutes; the "Next 2 hours" view is a NOAA HRRR forecast, not observed radar.