Shiva Purana

siva.sh/siva-purana/kotirudra-samhita/28/5

ग्रीष्मे पंचाग्निमध्यस्थो वर्षासु स्थंडिलेशयः ।। शीते जलांतरस्थो हि त्रिधा चक्रे तपश्च सः।। ५।।

sanskrit

He performed three types of penance. During the summer he stationed himself in the midst of five fires, during rainy days he lay on the bare ground and in the winter he stood within water and performed his penance.

english translation

grISme paMcAgnimadhyastho varSAsu sthaMDilezayaH || zIte jalAMtarastho hi tridhA cakre tapazca saH|| 5||

hk transliteration by Sanscript