Recent advancements in deep learning, particularly through Convolutional Neural Networks (CNNs) and Vision Transformers (ViTs), have led to significant progress in nighttime image deraining. However, current architectures still struggle to strike an optimal balance between computational efficiency and restoration performance. Moreover, existing methods often fail to fully exploit the intrinsic characteristics of low-light conditions and inadequately model the interaction between rain and illumination. To overcome these challenges, we propose NDMamba, a dual-prior-guided state-space model that addresses nighttime deraining by incorporating degradation cues related to both lighting and rain distribution. Inspired by the Retinex theory, which suggests that rain streak distribution is influenced by the reflectance component of a scene, we propose a Prior Extraction Module (PEM) to jointly model lighting conditions and rain degradation. Furthermore, we design a Prior-Guided Mamba Block (PGMB), which comprises a Lighting-Adaptive Vision State-Space Module (LVSSM) that incorporates illumination priors, and a Rain Distribution Guidance Module (RDGM) to enhance local features in a more refined manner. Extensive experiments demonstrate that NDMamba outperforms state-of-the-art methods on both synthetic and real-world benchmark datasets. Our code is publicly available at https://github.com/tandaily/NDMamba.