In our contribution and thanks to the use of extended QM/MM-MD simulations, we have succeeded in analyzing the energy alignment and the spin localization of the lowest triplet state of thymine embedded in a B-DNA environment. In particular, while we have shown that the triplet state is usually highly localized, with the participation of only one nucleobase, we have also clearly shown that the spin polarization induced by the thymine environment, and correctly captured only by the larger QM/MM partition, is fundamental to provide a better description of the triplet state energy. As a matter of fact, our highest value of theory provides values that are in good agreement with the experimentally inferred energy of triplet state of thymine in DNA. Interestingly, we have also shown that the triplet energy is undergoing rather important variations, especially in the case of the 4T model, as evidenced by the dispersion of the corresponding E values. This observation opens important questions regarding the photosensitization process. Indeed, the coexistence of low and high energy triplet states may also point to a more complicated photosensitization mechanisms, which could strongly a↵ect both the characteristic times and the quantum yields. Experimental determinations, which asses only the average macroscopic energy di↵erence present clear limitations, since they stay blind to subtle local e↵ects susceptible to play a key role in the further photophysical outcome. Furthermore, the variability of the energy alignment, together with the observed high mobility of the spin density, also necessitate to reconsider sequence e↵ects and the possible presence of hot spots that may lead to triplet accumulation in close spatial proximity, and hence eventually to DNA cluster lesions. These aspects may be seen even more crucial and dramatic in more complex environment as compared to our solvated, rather short, DNA double strand. In particular the mapping of the energy of triplet states in nucleosomal environment is particularly intriguing and could allow to underline the presence of specific sinks or spin traps. Even though we have provided the first atomistic and electronic resolved determination of the triplet energy of thymine triplet state, some important aspect are still missing. The use of semi empirical methodologies, such as density functional tight binding (DFTB) may allow to significantly increase the statistical sampling, hence providing more correlation from which the role of precise structural and dynamic factors could be more easily inferred. Furthermore, DFTB may allow a more systematic exploration of sequence e↵ects, which have been shown to play an important role , but also to increase the size of the QM partition to avoid spurious side e↵ects. Finally, e cient semiempirical methods will be necessary to bring the study to the nucleosomal realm without an insurmountable computational burden. However, DFTB, and more in general semiempirical methods, requires a tailored parameterization against either experimental results or ab initio methods. Due to the di culty of obtaining nucleobase resolved experimental determinations, we believe that our work may also serve as a solid base for the benchmark of the less expensive methods that we preview to use in the near future.