1. 【Open】the original image, 【Duplicate】one layer.
2. 【Curve Adjustment】, 【RGB】values: 109, 99.
3. 【Hue/Saturation】, values: 0, -39, 0.
4. 【Color Balance】, values: 0, 0, -34.
5. 【Selective Color】, 【Neutrals】: 0, 0, -20, 0.
6. 【Create a New Layer】, 【Fill】with d7b26c, 【Layer Mode】Overlay, 【Opacity】56%.
7. Drag the cloud material into the image, place it above the original image, set 【Layer Mode】to Soft Light. Use an eraser to remove everything except the sky, then merge visible layers (【Ctrl】+【Alt】+【Shift】+【E】).
(Note: Step seven is to add clouds to the sky.)