Weather Conditions and Reports

From month to month, Manitoba's ag weather program retrieves data every 15 minutes from equipment across the province. About 109 stations monitor air temperature, relative humidity, rainfall, wind speed/wind direction and soil temperature.

In addition to regular weather and soil reports, producers can access more specialized tools during the growing season. These tools include disease and crop condition reports, which helps producers determine the safest and most effective times to spray.


Latest weather and conditions

  1. Seven-Day Accumulated Precipitation (Oct 08 - 14, 2018) shows the amount of precipitation received across agro-Manitoba last week. The last three weeks have been cooler than normal and the precipitation was received as snow-rain mix. Areas close to the Ontario border in the eastern region received between 15 – 25 mm of precipitation with the highest amount at Sprague Lake with a total of 25.2 mm.  
  2. Total Accumulated Precipitation (May 01 – Oct 14, 2018) showed that about three-quarter of agro-Manitoba have received between 250 – 310 mm of precipitation since May 1. The locations with less than 250 mm of precipitation since May 1 are areas east and south of the Dauphin Lake (Rorketon, Laurier, Ste. Rose); Moosehorn (Interlake); Boissevain, Brandon, Ninette, Glenboro (Southwest region) and Treherne, Elm Creek, Kane, Altona and Gretna (Central region). Areas south of Lake Winnipeg have received over 340 mm of precipitation.
  3. Percent of Normal Accumulated precipitation (May 01 to Oct 14, 2018) relates accumulated precipitation since May 1st to a 30-year historical record. Areas in the Northwest and Southwest regions close to the Saskatchewan border are close to normal or above normal precipitation mainly due to a single rainfall event which occurred in early June. About two-thirds of agro-Manitoba are between 70 – 90% of normal precipitation since May 01. 
  4. Soil Moisture (Oct 14, 2018, top 0-30 cm) shows that agro-Manitoba mostly has adequate to wet soil moisture condition due to recent persistent precipitation and cool weather. Areas along the Red river from Altona to St. Adolphe and tracking northeast to Lac du Bonnet are mostly wet. The map shows soil moisture in the top 0-30 cm when compared to the soil saturation level (maximum recorded at that station). 
  5. Total Accumulated Growing Degree Days (base 5°C) from May 01 to Oct 14, 2018 shows that the south central part of the province has accumulated the highest growing degree days (max 2018 GDD). The northwest region has the lowest accumulated GDD at 1,348 – 1,500. Growing degree days are calculated by averaging daily maximum-minimum temperatures and subtracting 5°C which assumes that growth does not occur below this temperature. Heat accumulation generally decreases from south to north. Heat unit accumulation remained unchanged from last week due to the cooler than normal air temperature that persisted across agro-Manitoba.
  6. Percent of Normal Accumulated Growing Degree Days from May 01 to Oct 14, 2018 shows the range in growing degree days for agro-Manitoba.  The climate normal is based on historical record over a 30-year period. Most locations had warmer than normal accumulated GDD throughout the summer. However, with the cool fall air temperatures, some locations, especially in the Northwest region as well as Windygates and Snowflake which have accumulated below 100% of normal accumulated GDD. Wawanesa has the highest above normal GDD accumulation at 14% warmer than normal since May 01.
  7. Total Accumulated Corn Heat Units from May 01 to Oct 14, 2018 shows that the southern areas of the central region of the province received the greatest accumulated corn heat units (maximum of 3101 units). Morden, Altona and Letellier have accumulated over 3000 CHU. Heat accumulation generally decreases from south to north. Corn heats units are similar to growing degree days given they both assume that growth increases with increasing temperature but they are calculated differently.  Corn heat units calculates the day and night temperatures separately.  It is assumed that no growth occurs with night temperatures below 4.4°C or day temperatures below 10°C . Maximum growth occurs at 30°C and decreases with higher temperatures. 
  8. Percent of Normal Accumulated Corn Heat Units from May 01 to Oct 14, 2018 shows above normal CHU accumulation at most agro-MB regions (ranging between 91 – 109%). Areas around Wawanesa, Elm Creek, Steinbach and Minnedosa are between 8 – 9% warmer than normal based on the accumulated CHU this season relative to historical normal. The climate normal is based on historical record over a 30-year period.
  9. Total Accumulated Physiological Days (P-Days) from June 01 to Oct 14, 2018 shows greater heat accumulation in the central and southwest regions of agro-Manitoba. Similar to GDD and CHU, the P-day provides an indication of heat accumulation. However, it uses 7°C as the minimum air temperature for growth and development; rapid growth at 21°C and maximum growth at 30°C. P-Day is mostly used for Potato heat accumulation. A different start date (June 01) is used for P-days because accumulation commences at about 50% potato emergence. Other heat accumulation starts from seeding. Areas around Morden have the highest P-Day accumulation at 871 units. 
  10. Percent of Normal Accumulated P-Days from June 01 to Oct 14, 2018 shows that compared to historical accumulation. The persistent cool air temperatures have resulted in more locations being lower than normal P-day heat accumulation. Only four locations (Sprague, Teulon, Killarney and Minnedosa) have received above normal P-days heat accumulation. The heat indicators (GDD, CHU and P-Days) show that this growing season which started with been warmer than normal at most locations is ending at about normal heat accumulation.
  11. The average daily soil temperature across agro-Manitoba can be found at (   
  12. The Manitoba Weather Report shows weather information by individual weather station.

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Weekly Maps

(Higher resolution is available on request)

Crop Weather Report


Fall Frost Report


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Seasonal maps

Visit the Seasonal Reports page for information on progress in seeding and crop establishment, crop development, pest activity including weeds, insects and disease, harvest progress, crop yields and grades, fall field work progress, and status of winter cereal crop seeding and establishment. Information on haying progress and estimated yields, as well as pasture conditions is included.