Crop (corn) heat units

Crop Heat Units (CHU) are calculated on a daily basis, using the maximum and minimum temperatures in order to account for a crop’s negative response to higher temperatures.

The formula used to calculate the CHU value for a day is:

(1.8 × (Minimum Temperature − 4.4) + 3.33 × (Maximum Temperature − 10) − 0.084 × (Maximum Temperature − 10)²) ÷ 2.0

CHU values are only accumulated during the Growing Season, April 1 through October 31.

Data and Resources

Additional Info

Field Value
Last Updated April 17, 2026, 17:31 (UTC)
Created April 17, 2026, 17:31 (UTC)
contact_email agri-geomatics-agrog@agr.gc.ca
contact_person {"en": "Government of Canada; Agriculture and Agri-Food Canada; Science and Technology Branch,Agri-Geomatics-Agrog@agr.gc.ca", "fr": "Gouvernement du Canada; Agriculture et Agroalimentaire Canada; Direction générale de la science et de la technologie,Agri-Geomatics-Agrog@agr.gc.ca"}
criticality_level []
data_dictionary EPSG:3857,http://www.epsg.org/,8.3.4
geographic_scope []
open_canada_collection fgp
open_canada_date_published 2017-05-08 00:00:00
open_canada_keywords {"en": ["agclimate", "CH", "Temperature", "Farmlands", "Agriculture", "Crops", "Precipitation"], "fr": ["agclimat", "CH", "Température", "Terre agricole", "Agriculture", "Cultures", "Précipitation"]}
open_canada_subject ["nature_and_environment", "science_and_technology"]
sensitivity_level unrestricted
title_fr Unités thermiques de croissance (maïs)
update_frequency as_needed