check it http://maluta.github.io/blog/things-todo-with-twitter-archive/

tweets_per_year-hour.py

#!/usr/bin/python
# -*- coding:utf-8 -*-
import re
import csv
import sys

from datetime import datetime

tweets = csv.reader(open("tweets.csv"), delimiter=',', quotechar='"')

tweets_per_year = { 2008:0, 2009:0, 2010:0, 2011:0, 2012:0, 2013:0 }

tweets_per_hour  = { 0:0, 1:0, 2:0, 3:0, 4:0, 5:0, 6:0, 
                     7:0, 8:0, 9:0, 10:0, 11:0, 12:0, 
                     13:0, 14:0, 15:0, 16:0, 17:0, 18:0, 
                     19:0, 20:0, 21:0, 22:0, 23:0  }


format = '%Y-%m-%d %H:%M:%S' #2013-12-13 06:33:25 +0000

for tweet in tweets:
    date = tweet[3]
    if date != "timestamp":
        date_object = datetime.strptime(date[:-6],format)
        year = date_object.year
        for y in tweets_per_year:
            if y == year:
                tweets_per_year[year] += 1
        hour = date_object.hour
        minute = date_object.minute
        second = date_object.second

        if hour == 0 and minute == 0 and second == 0:
            pass
        else:
             for t in tweets_per_hour:
                 if t == hour:
                     tweets_per_hour[t] += 1

print tweets_per_year
print tweets_per_hour