Most often in May, 27 days.
Highest follower count seen that year: 2,975.
January
Jan 1 20:00–24:00 Jan 2 00:00–01:00, 14:00–19:00 Jan 4 16:00–17:00, 21:00–23:00 Jan 5 11:00–14:00, 22:00–23:00 Jan 6 22:00–24:00 Jan 9 20:00–22:00 Jan 10 22:00–23:00 Jan 11 23:00–24:00 Jan 16 20:00–21:00 Jan 18 13:00–16:00 Jan 19 15:00–19:00, 21:00–24:00 Jan 20 00:00–01:00, 15:00–17:00 Jan 22 17:00–18:00 Jan 23 07:00–12:00 Jan 24 05:00–08:00 Jan 26 04:00–08:00 Jan 27 08:00–10:00 Jan 28 07:00–08:00 Jan 29 04:00–07:00, 19:00–20:00 Jan 30 05:00–08:00
February
Feb 2 10:00–17:00 Feb 3 10:00–14:00, 18:00–21:00 Feb 4 11:00–12:00, 16:00–20:00 Feb 5 10:00–11:00, 20:00–23:00 Feb 8 17:00–20:00 Feb 9 21:00–22:00 Feb 10 11:00–13:00, 21:00–24:00 Feb 11 18:00–21:00 Feb 12 23:00–24:00 Feb 13 00:00–02:00, 19:00–23:00 Feb 14 01:00–02:00, 20:00–22:00 Feb 15 04:00–07:00, 22:00–24:00 Feb 16 00:00–02:00, 04:00–05:00 Feb 17 23:00–24:00 Feb 18 00:00–02:00 Feb 19 01:00–05:00 Feb 20 00:00–02:00 Feb 21 03:00–08:00 Feb 22 23:00–24:00 Feb 23 00:00–01:00, 04:00–06:00 Feb 24 01:00–07:00 Feb 26 01:00–08:00 Feb 27 08:00–10:00, 23:00–24:00 Feb 28 00:00–04:00
March
Mar 1 02:00–05:00 Mar 3 03:00–04:00, 06:00–08:00 Mar 4 03:00–06:00 Mar 5 07:00–08:00, 16:00–18:00 Mar 8 14:00–16:00 Mar 9 05:00–09:00 Mar 10 07:00–10:00 Mar 13 07:00–10:00, 21:00–24:00 Mar 14 00:00–04:00 Mar 15 23:00–24:00 Mar 16 00:00–02:00 Mar 17 22:00–24:00 Mar 18 00:00–01:00, 23:00–24:00 Mar 19 00:00–01:00, 10:00–12:00 Mar 20 05:00–07:00, 09:00–10:00, 22:00–24:00 Mar 24 06:00–08:00, 16:00–21:00 Mar 25 08:00–09:00, 11:00–14:00 Mar 26 08:00–10:00, 17:00–22:00 Mar 27 09:00–11:00 Mar 28 17:00–21:00 Mar 30 18:00–21:00 Mar 31 03:00–04:00, 11:00–12:00
April
Apr 1 15:00–16:00, 18:00–23:00 Apr 2 22:00–24:00 Apr 3 00:00–03:00 Apr 4 20:00–23:00 Apr 5 16:00–24:00 Apr 6 01:00–03:00, 22:00–24:00 Apr 7 00:00–01:00, 03:00–04:00 Apr 8 00:00–05:00 Apr 9 00:00–06:00 Apr 10 08:00–09:00 Apr 13 20:00–24:00 Apr 14 00:00–01:00, 09:00–13:00 Apr 15 01:00–07:00, 23:00–24:00 Apr 16 00:00–04:00, 09:00–10:00 Apr 17 03:00–08:00, 12:00–14:00 Apr 18 04:00–09:00 Apr 21 03:00–06:00, 12:00–13:00, 16:00–19:00 Apr 22 04:00–08:00 Apr 23 03:00–08:00, 14:00–15:00, 19:00–20:00 Apr 24 07:00–11:00, 16:00–19:00 Apr 25 03:00–07:00, 16:00–17:00 Apr 27 18:00–22:00 Apr 28 05:00–09:00, 22:00–24:00 Apr 29 00:00–01:00, 07:00–09:00, 19:00–20:00 Apr 30 03:00–05:00, 13:00–17:00
May
May 1 09:00–10:00 May 2 16:00–17:00 May 3 09:00–16:00 May 4 18:00–21:00 May 5 05:00–11:00, 17:00–20:00 May 6 08:00–10:00, 18:00–20:00 May 7 08:00–10:00, 14:00–17:00 May 9 16:00–20:00 May 10 08:00–10:00, 12:00–13:00, 19:00–24:00 May 11 08:00–12:00 May 12 11:00–15:00, 19:00–24:00 May 13 10:00–14:00, 20:00–23:00 May 14 09:00–10:00, 16:00–17:00 May 15 07:00–11:00, 16:00–17:00, 20:00–22:00 May 16 08:00–09:00 May 18 21:00–23:00 May 19 07:00–09:00, 12:00–13:00 May 20 19:00–21:00 May 21 07:00–10:00, 20:00–21:00 May 22 06:00–08:00, 21:00–24:00 May 23 00:00–01:00, 03:00–05:00 May 25 16:00–23:00 May 26 11:00–13:00, 20:00–23:00 May 27 12:00–16:00, 19:00–23:00 May 28 12:00–15:00, 19:00–20:00 May 30 04:00–09:00, 14:00–17:00 May 31 08:00–11:00
June
Jun 3 04:00–07:00 Jun 4 08:00–11:00, 22:00–24:00 Jun 5 08:00–10:00 Jun 6 08:00–11:00 Jun 7 09:00–11:00, 21:00–24:00 Jun 8 00:00–02:00, 08:00–11:00, 18:00–20:00 Jun 9 07:00–09:00, 17:00–22:00 Jun 10 17:00–21:00 Jun 11 08:00–11:00, 20:00–23:00 Jun 13 11:00–12:00 Jun 15 03:00–09:00 Jun 16 18:00–21:00 Jun 18 09:00–11:00, 14:00–20:00 Jun 19 05:00–07:00, 20:00–23:00 Jun 20 07:00–11:00, 16:00–21:00 Jun 21 05:00–09:00, 16:00–17:00, 19:00–22:00 Jun 22 06:00–10:00, 12:00–19:00 Jun 23 06:00–10:00, 15:00–21:00 Jun 24 07:00–12:00, 16:00–21:00 Jun 25 12:00–13:00, 19:00–22:00 Jun 26 07:00–11:00 Jun 27 07:00–08:00, 14:00–17:00, 20:00–21:00 Jun 28 07:00–09:00, 12:00–13:00 Jun 29 08:00–10:00, 12:00–20:00 Jun 30 05:00–07:00, 14:00–15:00, 18:00–22:00
July
Jul 1 09:00–12:00, 17:00–18:00, 21:00–24:00 Jul 2 00:00–01:00, 05:00–07:00 Jul 3 09:00–10:00, 14:00–15:00, 19:00–22:00 Jul 4 05:00–09:00 Jul 5 06:00–08:00, 11:00–12:00, 15:00–21:00 Jul 6 05:00–08:00 Jul 7 05:00–08:00 Jul 8 11:00–12:00 Jul 9 04:00–09:00, 14:00–15:00 Jul 10 09:00–11:00, 15:00–17:00 Jul 11 08:00–12:00 Jul 12 05:00–08:00 Jul 13 05:00–11:00 Jul 14 05:00–08:00 Jul 15 08:00–09:00, 18:00–20:00 Jul 16 04:00–08:00 Jul 17 06:00–09:00, 17:00–21:00 Jul 18 08:00–11:00 Jul 19 05:00–11:00, 14:00–17:00 Jul 20 05:00–09:00 Jul 22 18:00–21:00 Jul 23 08:00–11:00, 20:00–24:00 Jul 24 00:00–01:00, 05:00–07:00, 09:00–10:00, 16:00–18:00 Jul 25 18:00–20:00 Jul 26 17:00–21:00 Jul 27 06:00–07:00, 08:00–09:00, 17:00–18:00