Possible Clues:

• When tripled, a holiday song
• Phrase sung three times in a row in a holiday song
• When tripled, song that begins, "Oh, the weather outside is frightful"
• When tripled, song that begins, 'Oh, the weather outside is frightful'
• Winter song that mentions "some corn for poppin'"
• Winter song
• Song lyric following 'But as long as you love me so'
• Winter song refrain
• With 37-Across and 37-Across, a holiday song
• Seasonal song sentiment