Per USDA,
a 'suitable' day
is one where weather and field conditions allowed producers to work in fields a major portion of that day. Dates indicate observation for week ending
Rather than considering the number of days suitable for fieldwork each week,
it is useful to consider how many days were available between specific dates in the past.
The vertical blue and green lines represent the 15th to 50th (median) percentile number of fieldwork days, respectively.
The green shaded area is from the 15th to 45th percentile fieldwork days.