San Isidro is a small town located in Starr County, Texas. The region is characterized by a subtropical climate with hot summers and mild winters. Summers are typically long, hot, and humid, with temperatures often exceeding 100°F (38°C), while winters are short and mild, with average temperatures ranging from 60°F to 70°F (15°C to 21°C). The area receives about 20 inches of rainfall annually, with the majority occurring during the summer months.

Hydrologically, San Isidro is located near the Rio Grande River, which serves as a vital water source for the region. The river plays a significant role in supporting the local agriculture and providing irrigation water for crops.

Outdoor recreation opportunities in San Isidro are abundant. The area's natural beauty offers opportunities for various activities such as birdwatching, hiking, and wildlife observation. Nearby Falcon Lake provides opportunities for fishing, boating, and water sports. Additionally, the region is known for its hunting opportunities, attracting hunters seeking deer, feral hogs, and game birds.

Overall, San Isidro offers a diverse climate, proximity to the Rio Grande River, and numerous outdoor recreational options, making it an attractive destination for nature enthusiasts and outdoor adventurers.