with open('combined_file.csv', 'wb') as outcsv:
    writer = csv.DictWriter(outcsv, fieldnames=['Date', 'temperature 1',
        'Temperature 2'])
writer.writeheader()
with open('t1.csv', 'rb') as incsv:
    reader = csv.reader(incsv)
writer.writerows({'Date': row[0], 'temperature 1': row[1], 'temperature 2':
    0.0} for row in reader)
with open('t2.csv', 'rb') as incsv:
    reader = csv.reader(incsv)
writer.writerows({'Date': row[0], 'temperature 1': 0.0, 'temperature 2':
    row[1]} for row in reader)
Питонически добавить заголовок в файл csv