How far away is lightning? Count the seconds between flash and thunder
Count the seconds between the flash and the thunder, then divide by 3 for kilometers or 5 for miles. See why the rule works and where it goes wrong.
· 6 min read
Lightning & thunder guides
Everyone knows to count the seconds between lightning and thunder. These guides explain what that count actually measures and what changes the answer, then go further: how storms build their charge, how to read the radar behind them, where lightning strikes most, and which pieces of common safety advice are actively wrong.
22 guides · 142 min total
Distance and thunder
What the flash-to-thunder count measures, and everything that changes the answer.
The speed of sound and thunder: what actually determines the delay
The speed of sound changes with temperature, humidity, pressure and wind. See the exact Cramer equation and how much error the simple rule of thumb introduces.
· 7 min read
Heat lightning: real strikes too far away to hear
Heat lightning is ordinary lightning from a storm too distant for its thunder to reach you. See why the sound vanishes past 16 km and how far flashes carry.
· 6 min read
How lightning detection networks find a strike
Lightning maps locate strikes by timing radio pulses at multiple stations. See how time-of-arrival triangulation works and how accurate the results really are.
· 6 min read
The math and sources behind thunder timing
Every equation this map uses to time thunder: Cramer's speed-of-sound formula, slant range, wind advection, and the research each constant comes from.
· 12 min read
Storms and lightning
How storms build charge, what the radar behind them shows, and where and when they strike.
How to read weather radar colors
Radar colors show reflectivity in dBZ, not rainfall depth. Learn what green, yellow and red actually mean and why radar sometimes shows rain that never lands.
· 5 min read
How thunderstorms form
Thunderstorms need moisture, instability and lift. See how a storm builds through its three stages and why the mature stage produces the most lightning.
· 6 min read
Types of lightning and what each one means
Cloud-to-ground, intracloud, sheet, heat and ball lightning. What each type is, which ones detection networks see, and which are genuinely dangerous.
· 7 min read
Where lightning strikes most on Earth
Lake Maracaibo in Venezuela records about 233 lightning flashes per square kilometer a year. See why tropical land dominates and where Africa and the US peak.
· 6 min read
Which countries have the most lightning strikes?
Venezuela hosts the fiercest lightning hotspot, central Africa the most relentless storms, and Brazil the biggest yearly totals. See why, with live counts.
· 7 min read
When lightning happens most: season and time of day
Lightning peaks in summer afternoons because that is when surface heating is strongest. Why the time of day matters more than most people expect.
· 6 min read
Safety and damage
What actually protects people, buildings and electronics, and which advice is wrong.
Lightning safety and the 30-30 rule
If thunder follows lightning within 30 seconds, go indoors and stay there 30 minutes after the last thunder. Learn why both numbers matter.
· 5 min read
Lightning myths that get people hurt
Lightning does strike twice, rubber tyres will not save you, and lying flat is outdated advice. The common myths, and what the evidence actually says.
· 5 min read
Lightning strike survival: what happens when a person is struck
About 90% of lightning strike victims survive. What actually injures people, why cardiac arrest is the main cause of death, and what to do immediately.
· 6 min read
How lightning rods and protection systems really work
A lightning rod does not repel lightning or drain the cloud. It offers a preferred attachment point and a metal path to earth. See how the rolling sphere method places one.
· 7 min read
Why lightning destroys electronics without hitting the house
Most lightning damage to electronics comes from strikes that never hit the building. See how induced surges get onto wiring and what surge protection actually does.
· 7 min read
Unusual lightning
Winter storms, volcanic plumes, wildfire ignition, aircraft strikes and the open questions.
Thundersnow: why winter lightning is quiet and what it signals
Thundersnow is rare, quiet and usually means very heavy snow is falling. See why its thunder carries only 2 to 3 miles and where lake-effect storms produce it.
· 6 min read
Volcanic lightning: how an ash plume electrifies itself
Ash plumes generate lightning through rock fragmentation near the vent and ice higher up. See what the 2010 Eyjafjallajokull measurements showed about both mechanisms.
· 6 min read
How lightning starts wildfires, and why those fires get big
Lightning starts about 11% of US wildfires but burns 53% of the acres. See why continuing current matters more than peak current and what a holdover fire is.
· 6 min read
What happens when lightning strikes an aircraft
Airliners are struck about once a year each and keep flying. See how the Faraday cage, bonding and fuel tank inerting each handle a different part of the problem.
· 6 min read
How to photograph lightning without gambling on the shutter
Lightning photography is a waiting problem, not an exposure problem. Camera settings for night and day, why triggers exist, and how to stay behind cover while shooting.
· 6 min read
Ball lightning and the anomalies science has not closed out
Ball lightning, St Elmo's fire, earthquake lights and gamma-ray flashes. Which lightning anomalies are documented, which are explained, and which are neither.
· 8 min read