1. Seasonal factors: tourism usually has peak season and low season. If half a month happens to be the off-season, the restaurant may choose to close down to save costs.

2. Maintenance and renovation: The restaurant may need to carry out equipment maintenance or renovation and upgrading, which may take some time to complete, so it chose to close for half a month.

3. Personnel adjustment: The restaurant may need personnel adjustment, such as training new employees, firing employees or adjusting jobs, which may take some time to complete.

4. Market research and planning: Restaurants may need to conduct market research and planning to enhance their competitiveness and meet customers' needs, which may take some time to analyze and plan.