Weather Information for Your Farm: Making Good use of Your Computer

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 Information on local weather conditions and patterns may be helpful when determining farm management decisions. Spraying decisions (short term forecast for precipitation), crop, weed and pest development (heat accumulation and progress) and crop choices (days for maturity) can be addressed with good agroclimatic data.

There are many web locations where producers can obtain crop staging information. Montana State has a site with information on crop development using growing degree-days:
Using Growing Degree Days to Predict Plant Stages

Pest monitoring, pesticide applications or crop staging for harvest can involve Growing Degree day (GDD). Examples include head emergence of wheat for wheat midge or predicting grasshopper emergence patterns. Using argentine canola information from the Montana site, GDD development can be used to predict crop stages.

Crop Stage
GDD Range
Emergence Cotyledons completely unfolded
152 to186
Two True leaves
282 to 324
Four leaves
411 to 463
Flowering with at least one open floret on 50% or more plants
582 to 666
Flowering 50% complete
759 to 852
Seed fill begins 10% of seeds have reached final size
972 to 1074
Maturity 10% of seed has changed color
1326 to1445
Swathing 40% of seed on main stem has changed color. Swathing recommended at this stage
1432 to1557

GDD°C listed above range from the low values, representing development under dry conditions, to the higher values representing cool/wet growing conditions.
Recently information involving the use of GDD has been suggested for planning swath grazing seeding dates for cereals.

Alberta Agriculture has an excellent site, Agriculture and Climate Information Viewer (ACIS). ACIS is an interactive site that provides Alberta weather forecasts, climate and weather maps, and near real time weather data from over 350 meteorlogical stations located in Alberta.

Alberta Agriculture also provides Agricultural moisture situation updates. These updates are provided weekly during the growing season and monthly during the winter months.
Agricultural Soil Moisture Situation Updates

Agriculture and Agri-Food Canada has current condition maps that show growing season and “rolling” maps that show precipitation accumulation:
Drought Watch

Another source of great information is FarmZone. One valuable feature of this site is degree-day accumulations. Insect and crop development can be forecast with degree-day accumulations. Once emergence has been predicted then field scouting for the insect can begin. You can access this information at:

Once in the FarmZone site, click on the "historical" tab and select a range of dates to determine the accumulation of degree days.

Short-term weather patterns affect planning, especially for spraying. Below is a link for weather forecasts.
National Weather Service - Weather Prediction Center

Once on the site click on the map you are interested in, such as short range forecast, and it will enlarge. Areas where precipitation is expected can then be evaluated. The geographic extent tends to deal primarily with the United States, but covers most of the cropping zone in Alberta, excluding the Peace River Region.

With links to the above weather information sites you can answer many questions that are required to help in your farming decisions.

Prepared by Jim Broatch, Alberta Agriculture and Rural Development

For more information about the content of this document, contact the Ag-Info Centre.
This information published to the web on June 14, 2006.
Last Reviewed/Revised on May 19, 2015.