The Indus Dictionary Project
This is the ideograph for sky combined with the noun summer. Hence the translation is summer sky.
Kalibangan: Seal: K-29 a: Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 304: Collections in India: Suomalainen Tiedeakatemia.
There is only one extant example of this Indus sign. It is therefore, unfortunate that seal K-29 is broken, and we do not have access to the full inscription.
Indus Script Sign Number 92: Sign List of the Indus Script: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.