Alvin, Texas is located in Brazoria County and has a humid subtropical climate characterized by hot summers and mild winters. The city is situated on the Gulf Coastal Plain and is drained by the Chocolate Bayou and other small waterways. Hydrology constituents in the area include sediment, nutrients, and bacteria that can impact water quality. Outdoor recreation opportunities in Alvin include fishing and boating on Chocolate Bayou and nearby Lake Jackson, as well as hiking and birdwatching in the nearby Brazoria National Wildlife Refuge. The city also offers various parks and sports facilities for residents and visitors to enjoy.