If you like to know the exact time, all the time, and hate re-setting your clocks for daylight saving time, an atomic clock will help keep you on top of your schedule. The best atomic alarm clocks are synchronized to the NIST station in Colorado and have your local time zone setting so you’ll never be uncertain about the time again.
At-home atomic clocks are very precise, but they are also not technically atomic clocks. Genuine atomic clocks use atom frequencies to determine time, while atomic clocks for your home use radio signals to synchronize to a real atomic clock. In the U.S., these home atomic clocks are synchronized to The National Institute of Standards and Technology’s station in Colorado, which is the American government's official time. While atomic clocks automatically set and adjust to daylight savings, they still must be set to a specific time zone.
Most atomic clocks sold in the U.S. have every American time zone setting, but it's good to double check before buying one. You'll also want to consider what other features you need in an alarm clock in general. You may want a snooze button or multiple alarm settings if you like to sleep in, or date and day of the week settings to help you keep track of time in a broader sense. Some options have internal and external temperature readings, which are transmitted through wireless sensors, and USB charging capability can be another convenient feature. Some alarm clocks also have automatic backlights that adjust to the room’s lighting, while others have manual backlights.
Atomic clocks come in both battery-powered and plug-in designs. Plug-in designs don’t need to have their batteries replaced, but battery-powered clocks work through power outages and can travel, so both have their benefits.
If you want to know the exact time, all the time, here are four of the best atomic alarm clocks that you can buy on Amazon.
1. The Best Overall
- Size: 4.3 x 6 inches
- Time zones: 6
You can set alarms for weekdays and weekends with this dual-alarm atomic clock, which displays the alarm settings as well as the date, day of the week, and year. The different colors on the display help you get a good reading at a glance, and the internal temperature reading helps you dress for the day. This plug-in clock has a battery backup, as well as a snooze button and a USB port to charge your compatible devices.
One fan raved: “The clock set itself within a minute or two when I plugged it in and has been working very well since then. Another alarm clock in our house is not working well, and I will be buying another one of these.”
2. The Best With A Wall Mount
- Size: 5 x 6.45 inches
- Time zones: 7
This large atomic alarm clock can either be set on a tabletop or hung on your wall with the included mount. This battery-powered alarm clock requires three AAA batteries (which are not included), and it has a backlight that can be turned on for five seconds at a time by pressing the “snooze” button. This clock shows the date, day of the week, and indoor temperature, and has an icon that indicates when the alarm is set.
One fan raved: “What a deal, I just put in batteries, selected the timezone, and left it a few hours - it automatically set everything and is running great!”
3. The Best For Travel
- Size: 3.25 x 2.75 inches
- Time zones: 6
With a compact, foldable design, this battery-powered atomic alarm clock is great on your nightstand and on the road. Along with the time, it displays the indoor temperature (or outdoor temperature, if you take it camping), alarm setting, and day of the week, and the display can be set to five different languages. The time can be set to both 12- and 24-hour displays, and the backlight can be set to automatic or manual options. This clock runs on two AA batteries, which are included, and it comes in black, blue, and white.
One fan raved: “I have used many alarm clocks in the past and in my opinion this is the best of them all. Right size for travel, easy to setup and use. Specifically I like the auto night light feature. I have seen this feature in many table clocks that are plugged in but this is my first battery operated alarm clock that has the auto night feature. I am very happy with the purchase and it's worth every penny I spent.”
4. The Best With Indoor & Outdoor Temperature Readings
- Size: 11.1 x 6.61 inches
- Times zones: 7
This atomic alarm clock has chic faux wood siding and not only shows the date and day of the week, but it also the moon phases. It requires two AA batteries (not included), and displays both the indoor and outdoor temperature, which is transmitted from a weather-resistant sensor. The display language is adjustable, and this clock also has a display option that lets you know when the batteries need to be replaced.
One fan raved: “This clock is great. We bought it to keep in the bathroom. My husband and I get up very early, and it’s handy to be able to see the outdoor temperature first thing in the morning so we can decide how to dress for the day. I’ve always loved having a bathroom clock. It helps to keep us on schedule. It is, in fact, the only clock we have that isn’t on our phones.”