White walls and large sliding doors can suggest Mediterranean living without making a house comfortable. The architectural question is what happens on a hot afternoon, on a windy evening and during heavy rain. These conditions should be tested separately: the best response to one may complicate another. Coastal and inland sites also need different assumptions.
Heat: draw the shade where people sit
A terrace can be large yet offer no usable place for lunch. Put the table and chairs on the drawing, then check their shade at the times and seasons when the terrace will be used. A deep covered edge can become an outdoor room, but may reduce daylight further inside. Compare the terrace and the adjoining room together, not as separate design tasks.
Wind: an opening needs a usable route
Two opening windows do not by themselves demonstrate comfortable ventilation. Trace the route between them with the doors in their usual positions. Consider whether noise, insects, security or strong gusts will prevent those openings being used. A sheltered outdoor corner may be more valuable than an uninterrupted wraparound terrace. Natural ventilation is an opportunity to assess, not a substitute promised in advance for cooling or humidity control.
Water: the seamless threshold is a detailed junction
An interior floor apparently flowing onto a terrace is an attractive idea. It still needs a coordinated answer for levels, falls, drainage and waterproofing, with access for cleaning. Ask what happens when wind drives rain towards the doors or an outlet becomes obstructed. This is not a detail to leave until the paving is chosen; the threshold and terrace build-up can affect the section of the house.
Judge the system, not a single feature
Shading, insulation, glazing and ventilation need to be considered together; the US Department of Energy gives an overview of this combined cooling approach. The appropriate solution still depends on local climate data and a project-specific assessment. A large canopy or an opening window is not, by itself, proof of summer comfort.
Try this with your project
At the next review, ask to see three situations: lunch in the shade, the house with its usual doors closed, and rainwater moving away from the terrace threshold. These tests reveal more than an image of fully open glazing on a calm day.