Skandapurana 5.167.2

5.167.2

.. .. sūta uvāca .. ..
evaṃ rājyaṃ parityajya viśvāmitro dvijottamāḥ ..
himavantaṃ nagaṃ prāpya tapaścakre sudāruṇam .. 1 ..
varṣāsvākāśaśāyī ca hemaṃte salilāśayaḥ ..
pañcāgnisādhako grīṣme sthito varṣaśatatrayam .. 2 ..

Sūta said:
Having thus renounced his kingdom, O best of dvijas,
Viśvāmitra reached Mount Himavat and performed most dreadful austerity:
sleeping under the open sky during the rainy seasons, standing in water in winter,
and practicing the five fires in summer, he remained for three hundred years.