import csv
from datetime import datetime

filename = 'death_valley_2018_simple.csv'
with open(filename) as f:
    reader = csv.reader(f)

    dates, highs, lows = [], [], []
    for row in reader:
        current_date = datetime.strptime(row[2], '%Y-%m-%d')
        try:
            high = int(row[4])
            low = int(row[5])
        except ValueError:
            print(f'Missing data for {current_date}')
        else:
            dates.append(current_date)
            highs.append(high)
            lows.append(low)

