The NSF National Center for Atmospheric Research (NCAR) Education, Engagement, and Early Career Development (EdEC) seeks undergraduate Earth System Science students to participate as interns in the 2025 NCAR Earth System Science Internship (NESSI). The 2025 NESSI will run for 11 weeks, tentatively from May 19 - August 1, 2025. Interns work with NSF NCAR scientists to conduct research across all NCAR labs on a wide range of topics, including atmospheric science, computational science, engineering, and solar & space physics. Besides research in core geosciences, NCAR has a robust interdisciplinary mission to bring other fields to bear on substantial problems in climate, weather, and related disciplines. Thus, there is also a significant opportunity for data science, social science, and science education projects. Research projects are to be defined by student interest and the ability to pair the student with a mentor working in a similar field or topic.