Prominent sources of gas-phase opacity. The atmospheric gas pressure, p_gas (bar), at which the vertical wavelength-dependent optical depth, τ_x(λ), of species x reaches unity is shown for λ = 0.4 … 50 μm. All gas phase opacities are plotted at a spectral resolution of R = 1000. Four equatorial regions are considered: (i) the anti-stellar point (ϕ, θ) = (180°, 0°), (ii) the morning terminator (ϕ, θ) = (270°, 0°), (iii) the sub-stellar point (ϕ, θ) = (0°, 0°), and (iv) the evening terminator (ϕ, θ) = (90°, 0°). In regions containing clouds, we also show the atmospheric pressure where the cloud becomes optically thick, i.e. τ_cloud (λ) = 1, for comparison. The gas pressure at which the atmosphere of HAT-P-7b becomes optically thick varies by orders of magnitude between clear and cloudy regions.