Questions about a July Tenerife trip

[LiamHict]

I'm planning a ten-day trip to Tenerife in late July, and I'm trying to make an itinerary that leaves room for the weather rather than treating every day the same. The seaside temperatures look inviting, but I keep reading that a drive into the mountains can feel very different, especially if we stay out after sunset. We would like a few beach days, alongside a walk near Teide and a couple of shorter trips to towns away from the resort area. I have been looking at tenerife weather in july and august while deciding what clothes and timings make sense, but I would appreciate advice from people who have actually made a similar trip. Would you book the mountain outing for a fixed day, or keep that day flexible until the forecast is clearer? An early start is possible for us, although we do not want to spend the entire holiday racing from place to place. I am still trying to judge whether light layers are enough for an evening at higher altitude or if a proper jacket is useful. If you have done this in summer, how did you balance heat, driving time, and rest days? Specific examples would help us avoid overplanning.