The moisture content of wheat and barley is forecast during the harvesting period. Each hour the forecast model uses standard weather elements of air temperature, dew-point temperature, wind speed, amount of precipitation, global radiation and cloud cover. Over a period of four years, 1989-1992 inclusive, a five-day weather forecast is made every day for one month during the harvesting period. The forecasts were compared with those made using realized weather elements in this period. Forecasting the moisture content of wheat and barley up to three days ahead gives a better prediction of moisture content than with a longer forecasting period. Mean deviation in forecasting the moisture content of wheat and barley is at most 1)1 and 1)2% w.b. On average, barley has a greater deviation in the forecast moisture content than wheat. High moisture contents of the grains (about 25% w.b.) can be caused by low air temperature, low global radiation, high dew-point temperature, high wind speed, and precipitation. The low moisture content of cereals (10-30% w.b.) compared with cut grass destined for ensiling (50-85% w.b.) denotes that dew point temperature and wind speed are also important.