Whether and for how long you receive short-time working allowance depends largely on your employer's business situation. In times of the corona crisis, companies that have started short-time work by December 31, 2020 may extend it for up to 24 months according to current resolutions of the Federal Government, with the last possible date being December 31, 2021.
The seasonal short-time allowance (SKUG), which applies to the main construction industry, can be applied for from December to March inclusive, i.e. for the so-called bad weather period.