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Public Forecast Bulletins

There are two types of public weather forecast bulletins: the regular forecast bulletin, and the extended forecast bulletin.

The regular public forecast bulletin provides a description of the most significant weather conditions expected within the next two days (refer to Table 1 for exact time periods).

The extended forecast bulletin provides a description of the anticipated weather conditions beyond the time period covered by the regular public forecast bulletin: days three to seven. This extended forecast (also referred to as the long range forecast) is more general than the regular forecast.

Issuing time of forecasts

Although there are some regional differences, the regular and extended public forecast bulletins are most commonly issued three times a day, at 5:00 a.m., 11:00 a.m., and 4:00 p.m. local time. Issue times of a few bulletins are different from the national standard due to time zone differences within a region.

Time period covered by forecasts

The following table indicates the time period that the forecast covers for each of the three above-mentioned forecast issue times.

Table 1 : Time periods for the public forecast bulletin

Forecast Issued at:TodayTonightTomorrowDays Three to Seven
5:00 a.m.5:00 a.m. to 6:00 p.m.6:00 p.m. to 6:00 a.m.6:00 a.m. to Midnight6:00 a.m. to 6:00 p.m.
11:00 a.m.11:00 a.m. to 6:00 p.m.6:00 p.m. to 6:00 a.m.6:00 a.m. to Midnight6:00 a.m. to 6:00 p.m.
4:00 p.m.N/A4:00 p.m. to 6:00 a.m.Tomorrow: 6:00 a.m. to 6:00 p.m.

Tomorrow night: 6:00 p.m. to 6:00 a.m.
6:00 a.m. to 6:00 p.m.

Below, the same information can be seen along a timeline:

5:00 a.m. forecast issue

This type of graphic shows the time periods that are covered for a forecast issued at 5:00 a.m. See below for more description.

The timeline starts with the Today period, which covers the times of 5:00 a.m. to 6:00 p.m. It moves on to the Tonight period, which covers the times of 6:00 p.m. to 6:00 a.m. It then goes into the Tomorrow period, which covers the times of 6:00 a.m. to midnight. Lastly, the timeline includes the Days Three to Seven period, which covers the times of 6:00 am to 6:00 p.m.

11:00 a.m. forecast issue

This type of graphic shows the time periods that are covered for a forecast issued at 11:00 a.m. See below for more description.

The timeline starts with the Today period, which covers the times of 11:00 a.m. to 6:00 p.m. It moves on to the Tonight period, which covers the times of 6:00 p.m. to 6:00 a.m. It then goes into the Tomorrow period, which covers the times of 6:00 a.m. to midnight. Lastly, the timeline includes the Days Three to Seven period, which covers the times of 6:00 am to 6:00 p.m.

4:00 p.m. forecast issue:

 This type of graphic shows the time periods that are covered for a forecast issued at 4:00 p.m. See below for more description.

The timeline starts with the Tonight period, which covers the times of 4:00 p.m. to 6:00 p.m. It moves on to the Tomorrow period, which covers the times of 6:00 a.m. to 6:00 p.m. It then goes into the Tomorrow night period, which covers the times of 6:00 p.m. to 6:00 a.m. Lastly, the timeline includes the “Days Three to Seven” period, which covers the times of 6:00 am to 6:00 p.m.

Determination of forecast regions

Forecast regions are closely aligned with cities, communities and municipal boundaries. Local factors such as terrain, climatology, land cover and population patterns were used to define these regions. The names of the forecast regions generally correspond with those of the most prominent communities or the geographic regions. All official place names can be found in the Canadian Geographical Names Database.

Forecast time period terminology

Table 2a : Terms for Days One and Day Two

Time Period TermTime Period (local time)Sub-Time Period TermSub-Time Period (local time)
Morning6:00 a.m. – noonEarly morning6:00 a.m. – 9:00 a.m.
Morning6:00 a.m. – noonLate morning9:00 am – noon
Afternoonnoon – 6:00 p.m.Early afternoonnoon – 3:00 p.m.
Afternoonnoon – 6:00 p.m.Late afternoon3:00 p.m. – 6:00 p.m.
Evening6:00 p.m. – midnightEarly evening6:00 p.m. – 9:00 p.m.
Evening6:00 p.m. – midnightLate evening9:00 p.m. – midnight
Overnightmidnight – 6:00 a.m.n/an/a
Near Noonn/an/a11:00 a.m. – 1:00 p.m.
Near Midnightn/an/a11:00 p.m. – 1:00 a.m.
After midnightn/an/a12.00 a.m. – 3.00 a.m.
Before morningn/an/a4.00 a.m.– 6.00 a.m.

Table 2b. Terms for Day Three (4 p.m. forecast only)

Time Period TermTime Period (local time)Sub-Time Period TermSub-Time Period (local time)
Morning6:00 a.m. – noonn/an/a
Afternoonnoon – 6:00 p.m.Late in the Day3:00 p.m. – 6:00 p.m.

*Note: There are no time qualifiers for days four to seven. 

What information is included in the forecast?

Days One & Two:

The regular public forecast bulletin will always contain the following standard weather elements: (see the Weather Elements and when they are included in the forecast, for further details)

The following additional weather elements may also be included, provided certain criteria are met (see the Weather Elements and when they are included in the forecast for these criteria):

Days Three to Seven:

The extended public forecast bulletin will always contain the following standard weather elements (see the Weather Elements and when they are included in the forecast, for further details).

The following additional weather elements may also be included, provided certain criteria are met (see the Weather Elements and when they are included in the forecast for these criteria):

*Note: The normal temperatures for this period are the climatic normal temperatures for the grouping of regions indicated in the forecast. It is the Day Five normal temperature that is displayed in the extended bulletin. The normal temperatures can change as the grouping of regions in the forecast is changed.

The climatic normal temperatures are derived from 30-year averages of daily highs and lows.

Sample forecast

SAMPLE forecast #1 from the Weather.gc.ca

Sample forecast from the Weather.gc.ca web site. Details can be found below.

  1. Navigational toolbar that allows you to quickly link to other meteorological products and educational resources offered by Environment Canada; from radar and satellite images, marine information to fact sheets and Frequently Asked Questions.

  2. The Forecast Quick Link lets you easily browse through each city to find your local weather forecast.

  3. The watch/warning/advisory bannerwill warn you of all latest weather watches, warnings and advisories in effect for your region.  Clicking on the banner will take you directly to the full details of the message.

  4. The Current Conditions box displays all available weather information for the location chosen, along with the time and date that the information is valid.

  5. Forecast Iconsgive a visual description of what the forecast is for the next 5 days.  The icons will show the sky condition/precipitation,COP, high temperature and low temperature for each day.

  6. The Forecast Text is the complete forecast and gives more information than the forecast icons.  In addition to the information given in the icons, the text is more descriptive and gives the wind speed and direction. 

  7. The More Info tabs throughout the city page are drop down menus that will give you quick links to other useful information that pertains to the block that they are in.  The top tab will link you to the past 24 hour conditions, radar imagery and satellite imagery; the middle one will link you to the text forecasts, air quality and the UV index forecast; while the bottom tab will link you to record values and historical weather.

  8. The Historical Data provides us with a quick summary of yesterday’s temperatures and precipitation, along with normal temperatures for the period, sunrise and sunset.

Sample regular forecast (text bulletin)

* The numbers provide a description of the forecast text

  1. FPCN14 CWHX 041353
    FORECASTS FOR NEW BRUNSWICK ISSUED BY ENVIRONMENT CANADA AT 11.00 AM ADT FRIDAY 4 OCTOBER 2013 FOR TODAY AND SATURDAY.
    THE NEXT SCHEDULED FORECAST WILL BE ISSUED AT 4.00 PM.

  2. MONCTON AND SOUTHEAST NEW BRUNSWICK.
  3. FROST WARNING IN EFFECT.
  4. TODAY..MAINLY SUNNY. WIND BECOMING NORTHWEST 20 KM/H GUSTING TO 40
    EARLY THIS AFTERNOON. HIGH 17. UV INDEX 4 OR MODERATE.
    TONIGHT..CLEAR. WIND NORTHWEST 20 KM/H BECOMING LIGHT THIS EVENING.
    LOW PLUS 3 WITH PATCHY FROST.
    SATURDAY..MAINLY SUNNY. HIGH 16.
  1. This text is called the “title block”. It indicates the forecast area, the date & the time for which the forecast is. It also indicates when the next forecast will be issued.
  2. The forecast region name(s) is the full name of the region(s) or metropolitan area(s) for which the forecast is issued.
  3. These are called “status statements”. If there is a watch, warning or an advisory in effect for a forecast region(s), then status statements are indicated.
  4. The forecast text is broken into distinct periods (i.e. today, tonight, tomorrow) for ease of readability. See section 1.2 to learn more about the hours associated with the different time periods.

Sample extended forecast (text bulletin)

* The numbers provide a description of the forecast text

  1. FPCN51 CWTO 040820
    EXTENDED FORECASTS FROM SUNDAY 6 OCTOBER TO THURSDAY 10 OCTOBER FOR
    SOUTHERN ONTARIO AND THE NATIONAL CAPITAL REGION ISSUED BY
    ENVIRONMENT CANADA AT 5.00 AM EDT FRIDAY 4 OCTOBER 2013.
    THE NEXT SCHEDULED FORECAST WILL BE ISSUED AT 11.00 AM.

  2. CITY OF TORONTO.
  3. SUNDAY..CLOUDY WITH 70 PERCENT CHANCE OF SHOWERS OR THUNDERSTORMS.
    LOW 13. HIGH 20.
    MONDAY..CLOUDY WITH 60 PERCENT CHANCE OF SHOWERS. LOW 11. HIGH 16.
    TUESDAY..A MIX OF SUN AND CLOUD. LOW 11. HIGH 18.
    WEDNESDAY..SUNNY. LOW 8. HIGH 18.
    THURSDAY..SUNNY. LOW 11. HIGH 19.
    NORMALS FOR THE PERIOD..LOW 7. HIGH 16.
  1. This text is called the “title block”. It indicates the forecast area, the date and the time for which the forecast is. It also indicates when the next forecast will be issued.
  2. The forecast region name(s) is the full name of the region(s) or metropolitan area(s) for which the forecast is issued.
  3. The extended forecast bulletin covers day 3 to day 7.

Forecast Revision

Forecasts are revised when the difference between the forecast and actual conditions are such that public security and safety are at risk and/or when inconvenience to the public is thought to be extensive. A revision to the regular public forecast bulletin is initiated when one or more of the following criteria have been satisfied:

  • The non-occurrence of forecast precipitation or hazards (freezing rain, definite forecast of thunderstorms, etc.) and vice versa.
  • A difference in precipitation type (snow as opposed to rain/freezing rain and vice versa).
  • A significant change in the timing of forecast event(s).
  • A marked change in temperature regime is expected but is not occurring and vice versa.
  • When, to the opinion of the supervisor on duty, the latest forecast does not reflect what is actually occurring and what is expected to occur in the next few hours.

The extended forecast is rarely revised, however if it is revised, one or more of the same criteria above would have to be met to warrant the change(s).

Hourly Forecasts

In March 2014, Environment Canada introduced 24 hour forecasts for cities on weather.gc.ca. For each location with a forecast, there is a 24 Hour Forecast link in the upper right hand corner of the Forecast section. If you click on the link you will go to the weather forecast information for the next 24 hours. The hourly forecast information appears in a table and shows more detail than our text forecasts.

The table will be updated on an hourly basis, and will always provide 24 hours of information, starting with the next hour.

SAMPLE - 24 Hour Forecast

SPECIAL WEATHER STATEMENT IN EFFECT

This table shows the weather forecast for the next 24 hours.
Date/Time
(EST)
Temp.
(°C)
Weather ConditionsLOPWind
(km/h)
Wind Chill
19 February 2014
15:002
Cloudy
Cloudy
NilNW 20
*
16:002
Mainly cloudy
Mainly cloudy
NilNW 20
*
17:001
Mainly cloudy
Mainly cloudy
NilNW 20
*
18:001
Clearing
Clearing
NilNW 20
*
19:000
Partly cloudy
Partly cloudy
NilW 20
*
20:000
Clear
Clear
NilW 20
*
21:00-1
Clear
Clear
NilW 20
-7
22:00-1
Clear
Clear
NilW 20
-7
23:00-3
Clear
Clear
NilW 20
-9
20 February 2014
00:00-4
Clear
Clear
NilW 20
-10
01:00-6
Clear
Clear
NilVR 5
-8
02:00-6
Clear
Clear
NilVR 5
-8
03:00-7
Fog patches
Fog patches
NilVR 5
-10
04:00-7
Fog patches
Fog patches
NilVR 5
-10
05:00-7
Fog patches
Fog patches
NilVR 5
-10
06:00-7
Chance of flurries
Chance of flurries
LowSE 10
-10
07:00-7
Chance of flurries
Chance of flurries
LowSE 10
-13
08:00-5
Chance of flurries
Chance of flurries
MediumSE 10
-11
09:00-3
Chance of flurries
Chance of flurries
MediumSE 10
-8
10:00-1
Chance of flurries
Chance of flurries
MediumSE 10
-6
11:000
Snow
Snow
HighSE 15
*
12:000
Snow
Snow
HighSE 15
*
13:001
Rain. Risk of thunderstorms
Rain. Risk of thunderstorms
HighSE 30
*
14:002
Rain. Risk of thunderstorms
Rain. Risk of thunderstorms
HighSE 30
*

Likelihood of Precipitation as described in the public forecast as a chance of measurable precipitation for a period of time.

Nil: 0%

Low: 40% or below

Medium: 60% or 70%

High: Above 70%

* Value not significant.

What is included in the 24 Hour Forecast?

The information displayed will consist of the following weather elements:

  • Temperature: a value representing the temperature for the following hour.
  • Weather conditions: an image and short summary text representing the most probable weather in the following hour.
  • Likelihood of Precipitation (LOP): a category (Low, Medium, High) indicating the likelihood of precipitation in the following hour.  The Likelihood of Precipitation categories are given below, and are directly related to the Chance of Precipitation in the worded forecast:
    • Nil: 0%
    • Low: 40% or below
    • Medium: 60% or 70%
    • High: Above 70%
  • Wind: wind speed and direction for the following hour.  If there are gusts in the forecast, this information will also be displayed.  A wind direction of VR indicates a variable wind direction during the hour.
  • Wind chill: the wind chill for the following hour.  If there are no wind chill values to display for the entire 24 hour period, this column will not appear.  Further information on wind chill can be found at the following site: Learn more about Wind Chill.
  • Humidex: the Humidex for the following hour.  If there are no Humidex values to display for the entire 24 hour period, this column will not appear.  Further information on Humidex can be found at the following site: Learn more about Humidex.

Similar to the city pages, alert banners will display at the top of the page if an alert is in effect.