The weekly average figures suggest that grazing cows on most of our monitor farms will have suffered very little heat stress in the past week due to a combination of lower temperatures and higher levels of cloud cover. However on days when the sun did shine DHLI scores and heat stress risks rose. The inland, southern farms suffered the most heat stress and sunny weather on Sunday (yesterday) pushed our Berkshire farm into a high risk of heat stress which would have been very uncomfortable for any grazing groups.
The daily and weekly averages hide quite big daily variation. For example whilst the average daily heat stress at our Shropshire monitor farm was low this rose to mild heat stress on four afternoons and on Sunday afternoon there was a high level of heat stress with the DHLI rising to 44.