Yes! temp makes a huge difference. A 10 beat difference is not even very much under these conditions. When you are hot, the capillaries in your skin dilate this shunts more blood to the skin in an attempt to dump heat. Since you have only so much blood volume, this means less blood left over for the working muscles. Your heart has to work harder to make up for this and does so by beating faster. If it is hot when doing your outdoor training you should use that outdoor AeT. When you train in the cooler weather or indoors you’d be smart to retest.