It is recommended to choose a sunscreen with an SPF of at least 30 for a baby of 8 months old. Sunscreen should be applied 30 minutes before sun exposure and reapplied every two hours (or after swimming). Sunscreen should only be applied on exposed areas like the face, arms, and legs. It is also important to provide shade with long clothing and a hat for extra protection. Mineral-based sunscreens are recommended as they reflect light, cause fewer allergic reactions, and provide better protection. Look for a sunscreen with an SPF of at least 30, with most mineral sunscreens having an SPF of 50 or higher.