Washed James' hair this afternoon, and again no screaming. We even had a little water play out in the yard first, to get him in a good mood.
He wasn't happy, but he helped direct how the shampoo and rinse session went. He and I had quite the conversation, establishing that we were going to use a rinsing bowl, not the shower. I promised to not use the hair dryer. We agreed on the number of rinses and counted them together.
We've warmed up into the high 70s this week, which is bizarre, and I hope to be able to shampoo him later on in the week as well. Tomorrow we're even thinking of going swimming.