Most often in May, 31 days.
Highest follower count seen that year: 100,087.
January
Jan 1 13:00–20:00 Jan 3 10:00–21:00 Jan 4 10:00–20:00 Jan 5 09:00–20:00 Jan 6 08:00–20:00 Jan 7 09:00–15:00, 17:00–22:00 Jan 8 08:00–22:00 Jan 9 09:00–22:00 Jan 10 09:00–22:00 Jan 11 10:00–19:00 Jan 12 04:00–20:00 Jan 13 04:00–20:00 Jan 14 03:00–22:00 Jan 15 08:00–21:00 Jan 16 08:00–22:00 Jan 17 13:00–22:00 Jan 18 09:00–21:00 Jan 19 04:00–22:00 Jan 20 08:00–22:00 Jan 21 08:00–20:00 Jan 22 04:00–22:00 Jan 23 08:00–20:00 Jan 24 08:00–20:00 Jan 25 08:00–20:00 Jan 26 07:00–10:00, 12:00–19:00 Jan 27 04:00–20:00 Jan 28 10:00–20:00 Jan 29 07:00–08:00, 11:00–22:00 Jan 30 09:00–21:00 Jan 31 06:00–20:00
February
Feb 1 10:00–21:00 Feb 2 07:00–20:00 Feb 3 08:00–20:00 Feb 4 10:00–22:00 Feb 5 10:00–22:00 Feb 6 08:00–23:00 Feb 7 10:00–23:00 Feb 8 07:00–23:00 Feb 9 07:00–20:00 Feb 10 09:00–21:00 Feb 11 08:00–21:00 Feb 12 06:00–22:00 Feb 13 11:00–23:00 Feb 14 10:00–20:00 Feb 15 09:00–20:00 Feb 17 09:00–20:00 Feb 18 12:00–22:00 Feb 19 09:00–23:00 Feb 20 10:00–21:00 Feb 21 09:00–20:00 Feb 22 08:00–22:00 Feb 23 14:00–23:00 Feb 24 10:00–21:00 Feb 25 09:00–22:00 Feb 26 08:00–10:00, 12:00–21:00 Feb 27 08:00–23:00 Feb 28 09:00–21:00
March
Mar 1 10:00–21:00 Mar 2 09:00–19:00 Mar 3 10:00–19:00 Mar 4 10:00–21:00 Mar 5 09:00–21:00 Mar 6 08:00–16:00 Mar 7 08:00–15:00, 18:00–22:00 Mar 8 10:00–21:00 Mar 9 08:00–09:00, 12:00–17:00 Mar 10 08:00–21:00 Mar 11 09:00–20:00 Mar 12 08:00–09:00, 11:00–21:00 Mar 13 08:00–13:00, 16:00–20:00 Mar 14 08:00–22:00 Mar 15 10:00–21:00 Mar 16 07:00–19:00 Mar 17 08:00–20:00 Mar 18 08:00–18:00 Mar 19 09:00–21:00 Mar 20 09:00–22:00 Mar 21 09:00–15:00, 17:00–19:00 Mar 22 09:00–20:00 Mar 23 07:00–09:00, 12:00–20:00 Mar 24 07:00–20:00 Mar 25 08:00–20:00 Mar 26 09:00–20:00 Mar 27 08:00–21:00 Mar 28 10:00–15:00 Mar 29 06:00–20:00 Mar 30 06:00–20:00 Mar 31 10:00–21:00
April
Apr 1 05:00–15:00, 18:00–21:00 Apr 2 06:00–19:00 Apr 3 06:00–17:00 Apr 4 11:00–19:00 Apr 5 07:00–20:00 Apr 6 06:00–18:00 Apr 7 04:00–20:00 Apr 8 06:00–19:00 Apr 9 07:00–17:00 Apr 10 07:00–22:00 Apr 11 08:00–20:00 Apr 12 08:00–09:00 Apr 13 06:00–14:00, 16:00–19:00 Apr 14 09:00–21:00 Apr 15 07:00–09:00, 13:00–21:00 Apr 16 06:00–22:00 Apr 17 11:00–21:00 Apr 18 05:00–22:00 Apr 19 08:00–22:00 Apr 20 08:00–21:00 Apr 21 06:00–21:00 Apr 22 06:00–21:00 Apr 23 07:00–20:00 Apr 24 07:00–20:00 Apr 25 08:00–21:00 Apr 26 08:00–21:00 Apr 27 07:00–20:00 Apr 28 07:00–21:00 Apr 29 10:00–22:00 Apr 30 08:00–21:00
May
May 1 06:00–15:00, 20:00–24:00 May 2 00:00–01:00, 03:00–06:00, 10:00–23:00 May 3 08:00–24:00 May 4 07:00–24:00 May 5 00:00–01:00, 07:00–24:00 May 6 07:00–22:00 May 7 07:00–22:00 May 8 04:00–16:00, 20:00–24:00 May 9 07:00–22:00 May 10 07:00–23:00 May 11 07:00–16:00, 18:00–23:00 May 12 07:00–22:00 May 13 05:00–14:00, 16:00–22:00 May 14 07:00–23:00 May 15 06:00–17:00, 19:00–24:00 May 16 00:00–02:00, 07:00–12:00, 15:00–24:00 May 17 00:00–01:00, 08:00–11:00, 13:00–21:00 May 18 07:00–22:00 May 19 07:00–23:00 May 20 05:00–22:00 May 21 05:00–23:00 May 22 05:00–09:00, 12:00–23:00 May 23 06:00–23:00 May 24 07:00–23:00 May 25 05:00–23:00 May 26 06:00–23:00 May 27 05:00–09:00, 15:00–23:00 May 28 06:00–23:00 May 29 08:00–11:00, 13:00–21:00 May 30 05:00–22:00 May 31 05:00–24:00
June
Jun 1 06:00–22:00 Jun 2 06:00–22:00 Jun 3 05:00–10:00, 13:00–22:00 Jun 4 06:00–22:00 Jun 5 07:00–21:00 Jun 6 12:00–24:00 Jun 7 06:00–10:00, 12:00–21:00 Jun 8 05:00–07:00, 11:00–22:00 Jun 9 06:00–08:00, 11:00–23:00 Jun 10 04:00–09:00, 11:00–23:00 Jun 11 06:00–21:00 Jun 12 05:00–21:00 Jun 13 10:00–19:00 Jun 15 05:00–21:00 Jun 16 06:00–22:00 Jun 17 05:00–10:00, 15:00–24:00 Jun 18 06:00–22:00 Jun 19 06:00–17:00, 20:00–24:00 Jun 20 06:00–09:00, 12:00–24:00 Jun 21 08:00–13:00, 19:00–23:00 Jun 22 07:00–09:00, 15:00–23:00 Jun 23 06:00–23:00 Jun 24 06:00–08:00, 11:00–13:00 Jun 25 14:00–23:00 Jun 26 06:00–22:00 Jun 27 09:00–12:00, 15:00–18:00, 20:00–24:00 Jun 28 00:00–01:00, 06:00–17:00, 21:00–23:00 Jun 29 06:00–17:00, 19:00–23:00 Jun 30 07:00–09:00, 14:00–18:00, 20:00–24:00
July
Jul 1 07:00–17:00, 20:00–23:00 Jul 2 06:00–08:00, 11:00–16:00, 20:00–22:00 Jul 3 07:00–15:00, 19:00–24:00 Jul 4 06:00–16:00, 19:00–22:00 Jul 5 07:00–17:00, 19:00–24:00 Jul 6 07:00–16:00, 18:00–24:00 Jul 7 10:00–12:00, 14:00–24:00 Jul 8 16:00–24:00 Jul 9 07:00–24:00 Jul 10 00:00–01:00, 08:00–09:00, 12:00–17:00, 21:00–24:00 Jul 11 06:00–18:00, 23:00–24:00 Jul 12 00:00–02:00, 08:00–22:00 Jul 13 06:00–07:00, 10:00–23:00 Jul 14 05:00–10:00, 12:00–23:00 Jul 15 07:00–22:00 Jul 16 06:00–16:00, 18:00–23:00 Jul 17 05:00–15:00, 19:00–23:00 Jul 18 09:00–23:00 Jul 19 07:00–15:00, 19:00–24:00 Jul 20 06:00–08:00, 12:00–16:00, 18:00–21:00 Jul 21 01:00–03:00, 06:00–19:00, 22:00–24:00 Jul 22 00:00–01:00, 06:00–10:00, 12:00–24:00 Jul 23 07:00–18:00, 20:00–21:00, 23:00–24:00 Jul 24 00:00–02:00, 07:00–23:00 Jul 25 06:00–18:00, 21:00–23:00 Jul 26 07:00–10:00, 11:00–16:00, 17:00–24:00 Jul 27 06:00–09:00, 10:00–13:00, 14:00–15:00, 16:00–18:00, 19:00–21:00 Jul 30 17:00–21:00