Chomasa (Chaumasa) in Jainism is the four-month period of monsoon when monks stay in one place and lay followers intensify spiritual practices. The start date for 2025 is generally observed as Ashadha Shukla Ekadashi, about July 6, 2025, and the period ends around Kartik Shukla Ekadashi, about November 3, 2025. Do note that local pancang calendars can vary by sangh and tradition, but the broad window is early July to early November 2025. Also, depending on tradition, nearby observances like Paryushan may shift in relation to this Chaumasa window.

• Start: 6 July 2025
• End: around 3 November 2025

If you want, I can point you to more detailed, local schedules for a specific city or sangh.

You can read more here