What is the rain sounds page?
The rain sounds page is one of NumLM’s time tools with a built-in focus environment: a scenery theme for full-screen mode and an ambient-sound mixer. Noise, fan and heartbeat sounds are synthesised in your browser; rain, wind, waves, fire, stream, crickets, birds and cafe are short studio-generated loops of about 300 KB each, fetched only when you switch them on and kept for offline use. There is no time limit and nothing to sign up for. Your mix and theme are remembered on this device and carry over to the timer, Pomodoro and interval tools.
Rain level, thunder and what to mix in
The rain slider sets how loud the steady rain is; thunder is a separate slider with distant rolls every half minute or so, only while rain is on. Pair rain with wind at 15–25 % for a storm, or with brown noise for a muffled indoor feel. The rain and thunder loops are different lengths and each starts at a random point, so they do not line up into a pattern you notice. The rainy-window theme matches this page in full screen.
Rain for sleeping: timer and phone notes
Choose a timer length below the mixer so the rain fades out instead of running all night; the alarm sound starts as None here. Rain and thunder are loops of about 300 KB fetched the first time you switch them on and kept by the browser, so after that they play offline. On iPhone keep the screen on (dimmed) because Safari stops web audio on lock; Android and computers keep playing.
Sounds that play only while you focus
With the timer link on, the mix follows the timer: it fades out one and a half seconds before the alarm, so the alarm is never buried under rain, and in the Pomodoro and Focus timers it drops to 30 % during breaks and comes back when the next focus block begins; pausing keeps the sound by default, and you can change both in the panel.
Switching a sound on plays it at once, timer or not; the link only shapes the level. Switch it off and the sound ignores the timer entirely, except that an alarm still dips it. On the white-noise and rain pages there is no link.
Background tabs, phones and iPhone
On a computer the sound keeps playing when you switch tabs: browsers do not throttle a tab that is producing audible sound, and the fade-outs are scheduled on the audio clock ahead of time. Android phones keep playing with the screen on; iPhone Safari pauses web audio when the screen locks, so keep the tab on screen and leave Keep screen on enabled (it is on by default on phones).
Themes, full screen and battery
Three themes are free (night library, rainy window, forest) and five more come with the beta pack. In the page the theme only tints the timer card; press F or the full-screen button and the scene fills the screen behind the ring, darkened so the digits stay readable. The images are still pictures — no video loops — and the optional drifting motes are off by default and stop whenever the tab is hidden or your system asks for reduced motion, which keeps the page light on laptops and phones.
Share a mix, save it, and the beta pack
Copy mix link puts your sounds and theme into the address (`?amb=rain:60,wind:20&th=night-library`), so a friend opens the same setup with one click. Logging in unlocks the beta pack: nine more sounds (waves, campfire, stream, crickets, birds, cafe murmur, fan, air conditioner, heartbeat), five more themes, a theme that follows the time of day, and named mixes. The free sounds and themes stay free; the pack only adds. Listening tip: keep the device volume at or below 60 % for long sessions.