An atomic clock sets itself, stays accurate to the second, and springs forward and falls back for daylight saving time without you lifting a finger. The hardest part is deciding which one to buy. This guide walks through the main types, the rooms they suit best, and the features worth checking before you choose.
What makes a clock “atomic”?
Every self-setting atomic clock has a small radio receiver tuned to WWVB, the time signal broadcast by the National Institute of Standards and Technology from Fort Collins, Colorado. The signal covers most of the continental United States. Your clock listens for it, usually overnight, and corrects itself automatically, including the daylight saving time changes in March and November. Between updates it keeps time like a regular quartz clock.
Pick the type that fits the room
Analog atomic wall clocks
Best for: living rooms, kitchens, offices and classrooms. A classic dial is easy to read from across the room and fits almost any décor. Sizes run from about 10 inches for a kitchen or hallway up to 20 inches for a large wall or open office. Browse our atomic wall clocks.
Digital atomic clocks
Best for: desks, kitchens and anyone who wants more than the time. Large digits are easy to read at a glance, and many models add the day, date and indoor temperature; some also show the outdoor temperature from a wireless sensor. See our digital atomic clocks.
Atomic projection clocks
Best for: bedrooms. These clocks project the time onto your ceiling or wall, so you can check it in the middle of the night without lifting your head or reaching for your phone. Shop atomic projection clocks.
Atomic alarm clocks
Best for: the nightstand. Look for an adjustable or auto-dimming backlight, an easy snooze button and, on some models, a USB port for charging your phone. Shop atomic alarm clocks.
Outdoor atomic clocks
Best for: patios, porches, garages and pool areas. Outdoor models have weather-resistant cases, and many include a thermometer or humidity reading. Shop outdoor atomic clocks.
Atomic weather clocks
Best for: weather watchers. These combine self-setting time with indoor and outdoor conditions from a wireless sensor, and some add forecast icons. See our atomic weather clocks.
Features worth checking
- Readability: the farther away you will be, the larger the dial or digits should be. High-contrast faces are easiest to read.
- Night viewing: a backlight, lit display or projection makes a big difference in a bedroom.
- Power: most atomic clocks run on AA batteries. Some use a wall adapter with battery backup, and a few are solar powered.
- Extras: indoor and outdoor temperature, humidity, moon phase and alarms are common add-ons. Only pay for the ones you will use.
- Time zone and DST settings: make sure the clock lets you choose your time zone and switch daylight saving time on or off, which matters in Hawaii and most of Arizona.
- Quiet movement: if the clock is going in a bedroom or office, check whether it has a silent or sweep second hand rather than an audible tick.
Set it up for a strong signal
Put a new clock near a window for its first night, keep it a few feet away from TVs, computers and Wi‑Fi routers, and give it until morning to sync. If a clock ever misses a time change, our guide Why Didn’t My Atomic Clock Change for Daylight Saving Time? walks through the fixes step by step.
The bottom line
Choose the type that matches the room first: a wall clock where people gather, a projection or alarm clock where people sleep, and a digital or weather clock where you want information at a glance. After that, readability and the extras you will actually use should make the decision easy.
