import pandas as pd
import sys


ifile = sys.argv[1]
print(ifile)
df = pd.read_csv(ifile, sep='\t', header=None)
df.columns = range(1979,2021)
df = df - 273.15
df.index = pd.date_range('5/1/2020', '9/30/2020')
df = df.melt(ignore_index=False)
df = df.reset_index()
df.columns = ['day', 'year', 'value']
df['date'] = df.apply(lambda x: x.day.replace(year=x.year), axis=1)
df = df[['date', 'value']]
df.to_csv(ifile.replace('.txt', '.csv'), index=False)