Contact your concrete company that will pour your footings. They will adjust the mix for the temperature and other factors for the concrete you want in your footing. Tell them that it is for a footing and not an above grade slab as ground temp is different than air temp.
The Webmaster has closed this topic to new posts. Please go to top of topic for a full history of this topic as it may have been answered. We also recommend searching other topics to see if your question has been answered or starting a new topic.