I lost coverage March 15 and didn’t get new coverage until April 1. Am I considered uninsured for the month of March because I lacked coverage for part of the month?

Individuals with no coverage | Individual Responsibility Requirement (Individual Mandate)

No, if you are covered even one day during a month, you are considered to be insured for that month. Similarly, a person who is considered exempt from the individual responsibility requirement for even one day during a month is considered exempt for that month. (26 U.S.C. § 5000A (e)(4)).

Individuals with no coverage
Individuals with coverage
Coverage for small employers
Post enrollment issues