Stock picture of the AcuRite® atomic digital alarm clock 13131, operating, front view.

AcuRite® Atomic Digital Alarm Clock 13131 Review

Back in 2010, We’ve purchased three copies of the tabletop AcuRite® Atomic Alarm Clock 13131.  Most impressive about this time piece is that it receives radio signals from the master atomic clocks in Colorado, and synchronizes itself most every night to those signals.

So the time it displays is usually accurate to within one second of the official world time.  Yet this seemingly complex digital alarm clock cost less than $18, when just several years earlier, We paid over $50 for a similar device (not however, an AcuRite® clock though).  This is a great buy for all that you get in an atomic alarm clock. This clock remains about as modern an atomic clock as you can get, even though it was introduced a few years back.

Picture of the Model 13131 Digital Atomic Clock from Acu Rite, with its backlight energized.
Acu Rite Digital Atomic Clock, Model 13131

Features, Pros, Advantages, and Benefits

Modern, stylish look.  The thick plastic case shows a dark gray finished metallic contemporary look; pretty neutral in most any home or office décor.

Great for shelf or desk.  Though its display is big enough to qualify it as a wall style atomic table clock, this decently large clock is designed to set on a shelf, desk, bedside nightstand, or any flat surface that is out of the weather.

Features digital operation, with no moving parts to wear out.  Quite cool, because even after several years, this all-electronic timepiece performs just as well as the day we bought ours.

Very accurate time.  Of course, like all atomic clocks, the this one keeps highly accurate time as long as not too many days pass by without receiving the WWVB time sync signals via the built-in radio.

Current date also set automatically as well as the current time.  In addition, the 13131 also sets its date information from the WWVB atomic master clock radio transmissions, wirelessly.  No Internet subscription is required in order to fully utilize this clock’s accurate time keeping features.

Long battery life from standard batteries.  Since this clock is battery-powered by two AA batteries, it keeps ticking during power outages, with typical battery life exceeding a year when using fresh name brand long-life batteries. A fresh set of alkaline batteries can last more than two years in typical conditions; surprising given the extra large size of its display screen and the fact that the radio draws additional power each night when receiving the WWVB time signals.

Radio controlled for time accuracy.  Receives the WWVB radio control signals from the atomic master clocks near Boulder, Colorado at just about any location throughout the US.  So whether you live in a big city or off of a single-lane dusty drive in the country, this atomic clock will be able to function well for you.

Has signal strength bar graph readout.  The included radio signal strength meter built into the AcuRite® 13131 helps immensely in properly positioning the clock for best WWVB reception.

Informative display.  The 13131 also displays the date, day, alarm status, PM indicator, and current time zone alongside and underneath the large time digits that are easy for even me to read from several feet away.

Reads indoor temperature.  We especially like the deep blue yet bright LED backlight provided and the indoor temperature readout too.  This light fully illuminates the LCD display in a reasonably uniform fashion (no one part of the LCD display is brighter than any other – not much anyhow).

Large, high-contrast LCD display.  The 3-inch by 5-inch LCD display is pretty easy to read overall so long as the ambient light in the room is adequate.  Otherwise, you must use the backlight to see it.

Loud alarm but not obtrusive.  The alarm is loud enough to firmly arouse but not obnoxiously high in volume. It does not startle most people awake, but rather, gently nudges them.

Efficient LED backlight.  Plus, the LED backlight, when activated by pressing the snooze / light button on top of this digital clock, remains lighted for five seconds, and then automatically shuts off again, saving the batteries.  Further, since this backlight is LED, its battery drain is indeed modest.  So press that button a lot without worries about running the batteries down.

Features quick and simple setup.  Setting the 13131 is a snap.  Simply locate the SELECT button at the top of the clock on the right side panel.  Press and hold this button until the time zone element (the map of the US) begins flashing.  Then, press this button repeatedly until the element you want to set flashes.  Settable elements include time zone, daylight saving time operation, the time, and date.  Then, with the desired element on the display flashing, use the UP and DOWN arrow keys (also located on the clock’s right side panel) to change the value of that element.

Eminently affordable.  Costs less than $20.  This atomic clock is cheap enough that one need not even be concerned with how long the warranty is and what exactly it covers.  Should the device fail, it’s inexpensive to replace.  But for those that care, the AcuRite® 13131 comes with a 1-year limited warranty.

Silent.  Absolutely quiet operation; no ticking, unlike the analog style clocks that feature an advancing second hand.

Battery operated.  Requires no external power.  Therefore, can be operated remotely, off the grid, for years.

Picture of the side view of the AcuRite 13131 Radio Controlled Atomic Clock, showing most of the control buttons.
Side View of the AcuRite® Radio Controlled Atomic Clock, showing most of the control buttons.

Disadvantages, Cons, Problems, and Limitations

Indoor temperature reading can be incorrect.  The indoor temperature readout on the AcuRite® 13131 atomic alarm clock tends to run several degrees higher than numerous other thermometers we’ve tested.  All three of the 13131 clocks we own exhibit this as well.  Better calibration of the thermometer inside may be in order.

Must be angled correctly to receive time signals.   This alarm clock seems somewhat sensitive to position.  That is, it picks up the atomic signals best when you position it broad-side to Colorado so that the signals hit this unit at near right-angles.  If you position it at too great an angle from this, this atomic alarm clock might not always be able to receive enough radio control signal to lock to.

Does not receive time signals every night.  Even if you’ve positioned the 13131 properly, it does not receive the signal every night.  Sometimes it can go for days without “hearing” from the master atomic clocks at the National Bureau of Standards and Technology.  The signal is very susceptible to interference from electrical storms, power tools, and any device that produces arcing nearby.  But fortunately, the built-in clock keeps pretty accurate time without frequent refreshes from WWVB.

Not a projection clock.  his is NOT a projection atomic clock. That is, it does not project the current time and temperature readings on a wall for larger and easier viewing.  However, its oversized LCD backlit display more than makes up for this itty bitty shortcoming.

No weather information.  No indications of outside weather conditions are displayed here; just the temperature of the area surrounding this digital clock. Not intended to be operated outdoors.

Analog Time signals are old fashioned.  Uses rather old-style, analog radio signals for its time source which, as mentioned above, can be unreliable.  A handy improvement would be the addition of WiFi access to Internet time sources for users who have Internet.

Designed for US time signals.  This particular model is compatible with the National Bureau of Standards atomic time signals.  So, it likely will only work well in places inside or within a thousand or two miles of the US.  The further away you get, the less reliably these signals will be received.

Cannot schedule sync time.  The clock listens for the time signals only once per day, and at a preset time.  However, the best time each night to pick up the WWVB broadcasts may not always be at this preset time, as it depends on location of the 13131, time of year, and other factors.  Would be nice to be able to set this listen time, as well as the number of times each day this atomic clock listens for WWVB.

More for the tabletop.  It’s a little big to be used as a travel clock.

Our Rating

In the main, We’re quite impressed with the amount of and generally good reliability of the technology contained in this affordable AcuRite® 13131 atomic alarm clock.  But due to the temperature readout inaccuracy and the positional sensitivity discussed above, We’d rate this clock a bit lower than perfect, and give it a 90 out of 100.  Yet given its affordability, we nonetheless find the 13131 to be among the best atomic clocks we’ve played with.

Picture of the bottom View of the AcuRite® Wireless Atomic Clock, showing the battery compartment.
Bottom View of the AcuRite® Wireless Atomic Clock, showing the battery compartment.

Where To Buy The AcuRite® 13131 Atomic Alarm Clock

I found mine at Walmart, and this unit is widely available from online vendors.  However, We’ve not seen it in any other brick-and-mortar shops to date.


Revision History

  • 2017-02-21: Updated the tags list.
  • 2015-12-20: Added more appropriate tags.
  • 2015-10-03: Added appropriate tags.
  • 2015-02-17: Tweaked the content and reassigned categories and tags.
  • 2014-10-13: Added pictures and additional verbiage.
  • 2012-03-08: Originally published.