# 4.9 - Front Date File (*.fd)

The StateCU frost date file contains the last days in the spring when the average monthly temperature values are below 28 degrees and 32 degrees Fahrenheit, and the first days in the fall when the average monthly temperature values are below 28 degrees and 32 degrees Fahrenheit. The frost date data file is required for monthly and daily ET methods. Frost date data is provided for each climate station for years t1 through t2, described below. Missing data is accepted using a –999 place holder. The file must contain values (or -999) for all years in the simulation between nyr1 and nyr2, defined in the model control file (see Section 4.4). There must be a one-to-one correspondence between climate stations listed in the climate station data file (*.cli) and climate data included in the frost date file. An example is provided in Appendix A.

Row-Data Program Variable Description
Row 1 Format (6x, i4, 11x, i4, 7x, a3)
1-1 t1 Beginning year of frost date data
1-2 t2 Ending year of frost date data
1-3 idum3 CYR for calendar year
Row 2 Format (i4, 1x, a10, 5x, a5, 3(3x,a5))
2-1 tyr Year
2-2 tid Frost station ID
2-3 fd1 Spring 28 degree frost date
2-4 fd2 Spring 32 degree frost date
2-5 fd3 Fall 32 degree frost date
2-6 fd4 Fall 28 degree frost date.

Repeat for the number of temperature stations.

Repeat for each year t1 through t2.