If you’ve ever noticed your weather app alerting before Perry Weather, or showing a higher strike count during the same storm, you’re not seeing a malfunction. You’re seeing two different systems measuring two different things. Here’s what’s actually happening.
There are two types of lightning
Most people think of lightning as the bolt that hits the ground. That’s cloud-to-ground (CG) lightning, and it’s what directly endangers people outdoors.
But 70 to 80 percent of lightning never reaches the ground at all. It stays inside the storm cloud — building, moving, and discharging between different parts of the cloud as the storm develops. This is called in-cloud (IC) lightning. It’s real lightning, but it poses no direct ground-level threat.
Both types can be detected. The difference between networks isn’t whether they detect IC lightning — it’s how accurately they classify it, and what they do with it.
The three major lightning networks
Most lightning data in the U.S. and globally flows from one of three networks. Each was built with a different purpose, and understanding the differences explains a lot about why the data doesn’t always match across apps and systems.
Vaisala NLDN (National Lightning Detection Network) is a U.S.-focused precision network that has been operating since 1983. It uses more than 187 ground-based sensors distributed across the continental United States. Its strength is accuracy — it locates strikes within 84 meters and classifies lightning type with 95% precision. The National Weather Service, NASA, the U.S. Military, and the FAA all rely on it. Perry Weather is built on NLDN.
Earth Networks ENTLN (Total Lightning Network) is a global network of 1,800-plus sensors across more than 100 countries. It uses a wider frequency range than NLDN, which makes it sensitive to faint in-cloud signals early in a storm’s development. That broad sensitivity is its advantage — it detects storm activity earlier. But it also means it captures more noise, counts events differently, and classifies lightning type less precisely than NLDN. It powers consumer apps including WeatherBug.
TOA Systems / AccuWeather Lightning Network is a global network of 500-plus sensors deployed across more than 50 countries, built primarily for international markets. It detects both cloud-to-ground and in-cloud lightning using time-of-arrival technology and achieves strong performance in areas with dense sensor coverage. In December 2024, TOA Systems was acquired by AccuWeather and rebranded as the AccuWeather Lightning Network.
Perry Weather uses Vaisala NLDN
Perry Weather is built on the Vaisala National Lightning Detection Network — the same network trusted by the National Weather Service, NASA, the U.S. Military, and the FAA.
NLDN operates a dense grid of 187-plus ground-based sensors across the continental United States. When lightning strikes, those sensors detect the electromagnetic signal and triangulate the location within 84 meters — about three-quarters the length of a football field — in roughly 12 seconds. It detects both cloud-to-ground and in-cloud lightning and classifies each with 95% accuracy.
That classification precision is important. NLDN’s sensors are tuned to the strong electromagnetic signature of return strokes, which makes it exceptionally good at distinguishing a true cloud-to-ground strike from an in-cloud pulse — something other networks misclassify more often. When Perry Weather alerts, it’s because a confirmed, accurately classified strike was detected within your configured radius. Learn more about how Perry Weather’s lightning detection system works.
Consumer apps like WeatherBug use a different network
Apps like WeatherBug use the Earth Networks Total Lightning Network (ENTLN), a global network of 1,800-plus sensors designed to cast a wider net. Its sensors are tuned to detect faint in-cloud signals that traditional networks don’t pick up — which means it reacts earlier, before any lightning has touched the ground.
That early IC detection is genuinely useful for tracking storm development. But it also means ENTLN alerts can fire 5 to 30 minutes before a confirmed ground strike occurs — and in weaker storm cells, that ground strike may never come.
This is almost always the reason for a timing gap. The app isn’t faster. It’s reacting to an earlier, less specific signal. For a deeper look at why consumer lightning apps fall short for safety-critical decisions, read our full breakdown here.
Why the strike counts look different
Beyond timing, you may notice WeatherBug showing far more strikes than Perry Weather during the same storm. A few reasons:
Different sensors, different standards. ENTLN sensors operate across a wider radio-frequency range and are designed to detect both cloud-to-ground strikes and weaker in-cloud lightning pulses. That makes ENTLN useful for identifying electrically active storms early, but it can also record false positives from weaker in-cloud pulses. NLDN places a stronger emphasis on high-confidence detection and precise location, using stricter filtering and signal classification. The result is that ENTLN may show in-cloud activity Perry Weather doesn’t — not because Perry Weather is missing it, but because NLDN requires a higher confidence threshold before reporting it.
Pulses vs. flashes. A single lightning bolt contains multiple return strokes. NLDN groups those into one flash. ENTLN counts each pulse individually. One bolt can appear as one event in Perry Weather and several in an app.
Noise filtering. NLDN’s four-decade refinement process results in an outlier rate — strikes plotted in the wrong location — of around 0.1%. That conservative filtering produces a cleaner, lower-volume display.
The practical difference
When your Perry Weather system fires, a confirmed threat has been detected at a precise location within your safety radius. That’s the data point your safety protocol should be built on.
The earlier signal from a consumer app isn’t wrong — but it’s probabilistic. It tells you a storm is developing and electrical activity may be approaching. Perry Weather alerts on confirmed, accurately classified lightning — whether cloud-to-ground or in-cloud — detected within your configured radius. The difference is precision, not scope.
For a safety decision that puts people in motion, that distinction matters. See how organizations are using Perry Weather’s lightning detection and warning system to protect their people and operations.
