The Pell Grant, while offering substantial financial support for low-income students pursuing higher education, historically covered only the costs of two full-time semesters per year and did not include assistance for summer courses. Research has consistently demonstrated that continuous enrollment throughout the academic year enhances college persistence and degree completion. In response to this understanding, the Summer Pell (SP) program was introduced in the summer of 2009, providing eligible low-income students with an additional grant to cover summer tuition and related expenses. However, after a brief period of operation, the SP program was discontinued in 2011, only to be reinstated in 2017. We utilize administrative data obtained from New York City in the context of differences-in-differences analyses spanning both program periods, and find that SP-eligible students exhibited a higher retention rate in the fall of their second year, achieved higher rates of associate's and bachelor's degree attainment, and experienced greater earnings gains up to nine years after college entry compared with SP-ineligible students. Our analysis of heterogeneity further underscores that the benefits of the SP program were pronounced among Black students and older students.