The literal agricultural practice of harvesting forage grasses during a stretch of clear, dry weather. Cut grass must dry in the field to a specific moisture content before it can be baled; if it gets rained on while drying, it loses nutritional value and can rot. Farmers closely monitor weather forecasts to time this operation perfectly.
Heard on the job
The forecast shows three dry days starting tomorrow, so get the mower-conditioner ready because we need to make hay while the sun shines.