I'd use the Select geoprocessing tool to accomplish this. If you make a folder with only these 17 weather station files this aught to do the trick:
# Path to your 17 weather station files (all in one folder by themselves)
arcpy.env.workspace = r'...'
# This is the output file path
output = r'...'
for lyr in arcpy.ListFiles():
# This variables might start at 1 depending on your data
year = 0
#These variables depend on what your fields are named
yearField = "theYear"
monthField = "theMonth"
# Loop through each year, set SQL clause based on current year
while year < 10:
yearClause = '"' + yearField + '" = ' + "'" + str(year) + "'"
month = 0
#Loop through each month, add current month to SQL clause
while month < 12:
# This is the SQL statement to select the correct year / month
whereClause = yearClause + ' AND ' + '"' + monthField + '" = ' + "'" + str(month) + "'"
# This is where you actually create the layer (make sure your output filename makes sense)
arcpy.Select_analysis(lyr, output + str(year) + "_" + str(month), whereClause)
month += 1 # increment counters
year += 1