This research introduces DARES, a dataset for assessing the readability of Arabic text in Saudi school materials. DARES compromise of 13335 instances from textbooks used in 2021 and contains two subtasks; (a) Coarse-grained readability assessment where the text is classified into different educational levels such as primary and secondary. (b) Fine-grained readability assessment where the text is classified into individual grades.. We fine-tuned five transformer models that support Arabic and found that CAMeLBERTmix performed the best in all input settings. Evaluation results showed high performance for the coarse-grained readability assessment task, achieving a weighted F1 score of 0.91 and a macro F1 score of 0.79. The fine-grained task achieved a weighted F1 score of 0.68 and a macro F1 score of 0.55. These findings demonstrate the potential of our approach for advancing Arabic text readability assessment in education, with implications for future innovations in the field.