As an AI language model, I don't have a way to verify the existence of a Dublin Sports Grounds Park in California. However, I can inform you that the city of Dublin in California has several parks, including Dublin Heritage Park and Shannon Park, which offer hiking trails and recreational amenities. Visitors can enjoy outdoor activities such as picnics, fishing, and playing sports in these parks. Dublin is also known for its St. Patrick's Day celebration and the Dublin Farmers' Market, which takes place on Thursdays during the summer and fall months. The best time to visit the city of Dublin is during the spring and fall when the weather is pleasant and there are fewer crowds.