Ultimately, the best time for your visit will depend on your personal preferences, such as your desired weather conditions, tolerance for crowds, and the specific activities you plan to engage in while at Villa Borghese.
In terms of weather, spring (April to June) and fall (September to October) are considered the best times to visit Rome, including Villa Borghese. During these seasons, the temperatures are generally mild, the gardens are lush and vibrant, and there are fewer tourists compared to the peak summer months.
If you want to avoid crowds and enjoy a more leisurely visit, consider going during weekdays, as weekends tend to be busier with tourists and locals. Early morning and late afternoon hours are usually less crowded and offer pleasant lighting for photography.