[SAMU-I / ATSU-I]

It means 'COLD/HOT' but only for weather. You can say ' KYOO WA SAMU-I' as 'It's cold today' or 'KYOO WA ATSU-I' as 'It's hot today. If you put 'KATTA' instead of 'I' like ' SAMU-KATTA', it would be past tense. ' KINOO WA SAMU-KATTA' means 'It was cold yesterday'.