Web clock (Official times across Canada)

Java web clock

Click on a map to start the clocks

Or try our static web clock

Official times across Canada

The above time zone map runs a clock in each Canadian time zone. UTC (Coordinated Universal Time - the modern implementation of Zulu time or GMT) is also shown. For more information on Canadian time zones consult the following section Time zones & daylight saving time.

The map is a Java applet that gets its time initially from Canada's official time source: NRC's atomic clocks. The time offset of your computer from NRC official time is displayed at the top of the map. The network delay is removed. The offset is calcuated once. After that the clocks will drift along with your computer's clock. After 10 minutes, the browser will return to this home page.

To run these clocks, you will need a Java enabled browser with "Enable Java" set in the configuration options. If the time does not display correctly on your system, try clicking refresh. Check the technical notes below. If it still does not work, then you can try using the static web clock.

A box at the top of the sceen will show the offset your computer clock has with respect to official time. If this offset is a few seconds, you can adjust your computer's clock manually or automatically with a Network Time Protocol (NTP). If this offset is thousands of seconds, then check your computer's settings for the date, the time zone, or the daylight saving time setting.

Technical notes

The clocks are running in Java applets that were loaded with the web page. To check to see if your browser is java enabled, do the java test at the Java home page. If you need to download the Java Runtime Environment (JRE) for your browser, follow the instructions at the Java home page. The java applet needs to communicate with an NRC time server. It uses UDP port 7501 to exchange packets. If you are using a firewall, you may need to open this port for incoming traffic.

The applet uses the SNTP protocol to request time from the NRC time server. The exchange of time stamps allows it to calculate the network delay and time offset with your computer's clock. Therefore the time displayed, attempts to compensate for these errors. The SNTP protocol can not compensate for network asymmetries, so you may see small differences each time you refresh the page.

A Java applet does NOT adjust your computer's clock. It runs in a safe environment and can not affect your computer. However if you make adjustments to your computer's clock, either manually or automatically with some Network Time Protocol (NTP), the applet will have to restart and get a proper time reference again. You will see a message in the message box, the display will stop for 5 seconds and you will hear a ding. In some operating systems, the system clock may be adjusted by simply opening an application. If you need to maintain accurate time on your computer, you should use a Network Time Protocol (NTP). Some operating systems may already have one built in.