Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

WWVB Station Outages

Since October 29, 2012 at 1500 UTC (9:00 AM MDT), NIST Radio Station WWVB has been broadcasting a phase modulation (PM) time code protocol that has been added to the legacy AM/pulse-width-modulation signal. This enhancement to the broadcast, which has been tested throughout 2012, provides significantly improved performance in new products that are designed to receive it. Existing radio-controlled clocks and watches are not affected by this enhancement, and continue to work as before. A detailed technical description of the new format can be found here.

Disciplined oscillator products that track and lock to the 60 kHz WWVB carrier and were designed to work as frequency standards, will not work with the PM signal and will now become obsolete. A few radio controlled clocks that used information from the carrier – specifically the Spectracom NetClock and receivers manufactured by True Time during the 1970s and 1980s – will no longer be able to read the time code and will also be obsolete. For more information, contact the station broadcast manager Matthew Deutch (matthew.deutch [at] (matthew[dot]deutch[at]nist[dot]gov)) or (303)-497-3914.

Notice: From approximately April 7, 2024, 0h UTC, WWVB's south antenna has been disabled as a result of damage from wind gusts in excess of 90 MPH. WWVB continues to operate at reduced overall power using its north antenna only.

Broadcast Outages for WWVB

WWVB Home2003 Outages2004 Outages2005 Outages2006 Outages2007 Outages2008 Outages2009 Outages
2010 Outages2011 Outages2012 Outages2013 Outages2014 Outages2015 Outages2016 Outages2017 Outages
2018 Outages2019 Outages2020 Outages2021 Outages2022 Outages2023 Outages  

During normal operation, the 60 kHz signal from WWVB is transmitted 24 hours per day, 7 days a week. The table includes periods when the signal was off or intermittent for more than 5 minutes.

DateMJDBegan (UTC)Ended (UTC)
15 July 20246050604430453
14 July 20246050503130329
07 July 20246049801140215
30 June 20246049102590313
15 June 20246047603430351
02 June 202460463 0133
01 June 2024604622324 
10 April 20246041009100921
Created November 2, 2010, Updated July 15, 2024