A cold April a barn will fill.

The proverb presents a cold April as a hopeful sign for farming: an uninviting spring may still lead to a harvest plentiful enough to fill a barn.

It contrasts present discomfort with future abundance. Rather than treating chilly weather as a sign of a poor growing season, it imagines a good harvest following it.

Use the saying when discussing a cold April and the hope of a good harvest. It expresses a hopeful agricultural expectation, not a guarantee about the outcome of a particular growing season.