Use the free Thunderstorm Sound Generator below: your data never leaves your browser — all work happens on your device, and nothing is uploaded to any server.
Rain, thunder, and the feeling of being safe indoors
There is a specific pleasure to a thunderstorm heard from indoors: the rain against the window, the low roll of distant thunder, and the knowledge that you are warm and dry while the weather does its worst outside. That combination is deeply relaxing for many people, and it is the experience this generator recreates. It plays steady rain as its base, and then fires thunder bursts at random intervals, each one a low, rolling rumble that swells and fades over several seconds, with a flash on screen to mark the clap. Nothing is recorded: the rain is filtered noise, and the thunder is a burst of low-filtered noise shaped with a slow attack and a long decay, all computed in your browser.
The randomness matters. Real thunder does not arrive on a schedule, and a thunder sound that arrived every thirty seconds exactly would quickly feel mechanical and lose its effect. This generator draws each gap from a range that depends on your thunder frequency setting: rare thunder waits twenty-five to sixty seconds between claps, occasional thunder waits fourteen to thirty-five seconds, and frequent thunder waits eight to twenty seconds. Within each range the exact gap is random, so you can never predict the next clap, which keeps the experience feeling like weather rather than a playlist.
Storm intensity and thunder frequency: two different controls
Storm intensity controls how heavy the rain is and how loud the thunder swells. At low intensity the rain is light and the thunder is a distant murmur, like a storm several miles away. At high intensity the rain thickens into a downpour and the thunder swells louder and longer, like a storm overhead. Thunder frequency, by contrast, controls only how often the claps come, not how loud they are. That separation lets you build the storm you want: a distant storm is low intensity with rare thunder, a dramatic overhead storm is high intensity with frequent thunder, and a gentle sleep storm is moderate intensity with occasional thunder.
Start with moderate intensity and occasional thunder, which is the most broadly pleasant combination, and adjust from there. If the thunder startles you, lower the intensity before changing the frequency, because loudness is usually the problem, not timing. If the storm feels too calm, raise the frequency first, because more frequent thunder adds drama without making any single clap louder. Give each change a minute to settle, since the random gaps mean a single quiet minute does not mean the storm has gone calm.
Thunderstorms for sleep, focus, and atmosphere
For sleep, thunderstorms work through the same masking as rain, with an added benefit: the slow thunder swells are too gradual to wake most sleepers, unlike sudden real-world sounds, so they add atmosphere without adding disturbance. Some sleepers find the thunder itself soothing, a low sound that feels like the world settling. Others prefer the thunder rare, so it stays a background event rather than a feature. Either way, the sleep timer lets the storm stop after you fall asleep, or you can let it run all night if you wake at small sounds.
For focus, thunderstorms suit long, immersive tasks: writing, reading, coding, or drawing. The rain masks the environment, and the occasional thunder gives the session a sense of scale and drama that flat noise lacks. For atmosphere, the generator serves as background for a quiet evening, a storm-themed gathering, or a reading session, with the screen flash adding a visual cue that a clap has arrived. It is not a substitute for real weather, and it should not be used where you need to hear alerts, but as an everyday comfort sound it is one of the richest the site offers.
What is real here and what is not
Everything you hear is synthesised, and being clear about that is important. The thunder is not a recording of real thunder, which has a complex crack and roll that no simple synthesis fully captures. What the synthesis captures well is the low rumble and the slow swell, which are the parts of thunder that matter most for relaxation. The rain layer is the same filtered noise used by the rain generator, and the combination of the two layers is convincing enough that most listeners stop analysing it within a minute and simply enjoy the storm. If you want rain without thunder, the rain generator offers the same base alone, and if you want a slower, calmer water sound, the ocean generator offers waves instead.