Yes, sky‑clad (Digambar) monks can get sunburned in principle, because their skin is like anyone else’s. But in actual practice, serious sunburn is uncommon due to how they live:

1. Gradual lifelong exposure

- From very early in their monkhood they are exposed to open air and sunlight daily. - The skin slowly adapts and becomes thicker and darker (tanning), so it burns less easily over time.

1. Daily routine avoids harsh sun

- Vihar (walking) is usually done in the early morning or late afternoon, not in the peak midday sun. - During the hottest hours they are often in upashray, dharmashala, or shaded areas, engaged in svādhyāy, dhyān, or pratikraman. - They try not to sit or walk long in direct harsh sun unless necessary.

1. Simple, natural protection

- They do not use creams, lotions, or umbrellas, in line with aparigraha (non‑possessiveness) and simple living. - They may naturally take shade under trees, building edges, or walls while walking or resting. - Some parts of the body are protected simply by posture (e.g., squatting, folding arms, etc.).

1. Acceptance of bodily discomfort

- Whatever minor tanning, roughness of skin, or occasional irritation happens is accepted as part of tapas (austerity) and the natural result of the body’s karma. - The focus is on inner protection (right faith, right knowledge, right conduct) rather than constant concern for bodily comfort.

1. Difference from Śvetāmbars

- Śvetāmbara monks wear white clothes, so they are naturally protected more from direct sunlight on most of the body. - Digambar “sky‑clad” practice is a special form of aparigraha and tyāg; the lifestyle around it is arranged so that unnecessary harm (like repeated severe sunburn) is minimized while still keeping the vow.

So: biologically, yes, they could burn, but because of slow adaptation, careful timing of activities, and use of natural shade, strong sunburn is generally rare, and whatever minor effects occur are calmly accepted as part of the monk’s spiritual path.