BaalHabooze,
Only if you’re in the tropics. Jerusalem’s latitude is approximately 31.5 degrees north of the equator. On the summer solstice, the maximum (e.g., noontime) sun angle at that latitude is ~ 82 degrees, and on the winter solstice that angle is ~ 35 degrees. Assuming Sukkos falls out near the autumnal equinox, the sun angle at noon would be approximately 60 degrees, so even at noon the walls are casting a shadow.