Background: In recent years, the frequency and severity of climate-driven disasters, including wildfires, have posed significant challenges to the delivery of oncology care. Among various treatment modalities, radiotherapy stands is particularly vulnerable due to its reliance on consistent electrical power and daily treatment sessions. For patients receiving radiation treatment for locally advanced non-small cell lung cancer (NSCLC), even minor disruptions in treatment continuity have been shown to have a detrimental impact on overall survival. Methods: Patients undergoing definitive radiotherapy for nonoperative locally advanced NSCLC between 2004 and 2019 were selected from the hospital-based National Cancer Database, which captures approximately 70% of all cases in the United States. Disaster declarations were identified from the Federal Emergency Management Agency from 2004 to 2019. Exposed patients (n = 1,419) were defined as those who had a wildfire disaster declared in the county of the treatment facility during the exposure window (within 12 weeks of radiotherapy start date), while unexposed patients (n = 226,719) had no disasters declared within the same timeframe. Overall survival was defined as age when radiation therapy started and age of death, last contact, or study end. Cox proportional hazards was used for estimating hazard ratios (HRs) adjusted for sex, region, health insurance, comorbidities, facility type, lymph node involvement and concomitant chemotherapy. Survival estimates were weighted by the inverse of the probability of remaining uncensored at the end of the exposure window. Results: A total of 228,138 individuals were included in the study. Our preliminary data shows that exposed individuals were more likely to receive treatment in facilities located in western states, have no comorbidities, and have private health insurance coverage. Individuals whose facility had a wildfire disaster declared within 12 weeks of the radiation start date had worse overall survival (HR = 1.03; 95% Confidence Interval = 1.01, 1.06) compared to unexposed individuals with sensitivity analyses pending. Conclusions: Our study highlights the vulnerability of individuals undergoing radiotherapy for NSCLC to the hazards posed by wildfires. These findings underscore the urgent need for oncology institutions to prioritize the climate adaptation efforts aimed at safeguarding the needs of this vulnerable population.