Adrian Bloom gives a good comparative of the aureous Colorado Spruces in his book ‘Gardening With Conifers.’ He states ……….. “Selections with both golden-yellow growth and needles are P.p. ‘Aurea’ with its best color in winter; P.p. ‘Lutea’, deeper yellow, with gold on the needles only if exposed to light, and the compact P.p. ‘Stanley Gold’, with a good year-round color. Many of these golden and variegated selections are rather prone to spring frost damage and sunscorch so they are not always satisfactory garden plants, but this should not put off keener gardeners. All need good light but shelter from early morning sun.”
I will add that the picture attached to this shows a plant in the Chicago Botanical Garden. The picture was taken on a day in July in 1999 when the temp. was about 107 deg. F. The tree stood out from all of the surrounding plants clearly as a yellow-green plant. It did not seem to suffer at all from direct sunlight. It is not unusual for larger plants to better withstand sun burn in the summer. Often the color of larger plants is also less aureous than young plants.