Most often in May, 30 days.
Highest follower count seen that year: 6,716.
February
Feb 23 20:00–24:00 Feb 24 00:00–02:00, 20:00–24:00 Feb 25 00:00–02:00, 19:00–24:00 Feb 26 00:00–02:00, 19:00–24:00 Feb 27 00:00–02:00, 20:00–24:00 Feb 28 00:00–02:00, 19:00–24:00
March
Mar 1 00:00–02:00 Mar 2 19:00–24:00 Mar 3 00:00–02:00, 20:00–24:00 Mar 4 00:00–02:00, 19:00–24:00 Mar 5 00:00–02:00, 19:00–23:00 Mar 6 00:00–02:00, 19:00–23:00 Mar 7 00:00–02:00, 20:00–24:00 Mar 8 00:00–01:00, 19:00–24:00 Mar 9 00:00–01:00, 19:00–24:00 Mar 10 00:00–02:00, 19:00–24:00 Mar 11 00:00–02:00, 21:00–24:00 Mar 12 00:00–02:00, 19:00–24:00 Mar 13 00:00–02:00, 19:00–24:00 Mar 14 00:00–02:00, 19:00–24:00 Mar 15 00:00–01:00, 18:00–24:00 Mar 16 00:00–01:00, 19:00–24:00 Mar 17 00:00–02:00, 19:00–24:00 Mar 18 00:00–02:00, 20:00–24:00 Mar 19 00:00–02:00, 19:00–24:00 Mar 20 00:00–02:00, 19:00–24:00 Mar 21 00:00–02:00, 19:00–24:00 Mar 22 00:00–01:00, 18:00–24:00 Mar 24 03:00–10:00 Mar 25 04:00–10:00 Mar 26 03:00–10:00 Mar 27 04:00–10:00 Mar 28 04:00–11:00 Mar 29 18:00–24:00 Mar 31 02:00–10:00
April
Apr 1 02:00–10:00 Apr 2 02:00–10:00 Apr 3 00:00–06:00 Apr 5 18:00–24:00 Apr 6 00:00–01:00 Apr 7 02:00–10:00 Apr 8 02:00–10:00 Apr 9 02:00–10:00 Apr 10 02:00–10:00 Apr 11 03:00–10:00 Apr 12 19:00–24:00 Apr 14 02:00–10:00 Apr 15 04:00–10:00 Apr 16 02:00–10:00 Apr 17 02:00–09:00 Apr 18 02:00–10:00 Apr 19 19:00–24:00 Apr 21 02:00–10:00 Apr 22 01:00–10:00 Apr 23 01:00–10:00 Apr 24 04:00–10:00 Apr 25 02:00–10:00 Apr 26 19:00–23:00 Apr 27 00:00–01:00 Apr 28 02:00–10:00 Apr 29 03:00–10:00 Apr 30 00:00–10:00
May
May 1 00:00–09:00 May 2 00:00–06:00 May 3 21:00–24:00 May 4 00:00–01:00 May 5 01:00–10:00 May 6 00:00–10:00 May 7 00:00–10:00 May 8 02:00–03:00, 05:00–10:00 May 9 03:00–05:00, 07:00–10:00 May 10 19:00–24:00 May 12 01:00–10:00 May 13 03:00–10:00 May 14 03:00–09:00 May 15 02:00–10:00 May 16 00:00–09:00 May 17 19:00–24:00 May 18 23:00–24:00 May 19 00:00–07:00 May 20 01:00–08:00 May 21 01:00–09:00 May 22 02:00–09:00 May 23 00:00–10:00 May 24 19:00–24:00 May 25 23:00–24:00 May 26 00:00–10:00 May 27 03:00–10:00 May 28 00:00–10:00 May 29 01:00–09:00 May 30 01:00–10:00 May 31 19:00–24:00
June
Jun 1 00:00–01:00 Jun 2 00:00–10:00 Jun 3 00:00–10:00 Jun 4 01:00–10:00 Jun 5 01:00–10:00 Jun 6 01:00–09:00 Jun 7 01:00–07:00, 20:00–24:00 Jun 8 00:00–05:00 Jun 10 00:00–09:00 Jun 11 01:00–10:00 Jun 12 00:00–10:00 Jun 13 00:00–10:00 Jun 15 18:00–23:00 Jun 16 23:00–24:00 Jun 17 00:00–09:00 Jun 18 02:00–09:00, 23:00–24:00 Jun 19 00:00–09:00, 23:00–24:00 Jun 20 00:00–10:00 Jun 21 18:00–24:00 Jun 22 00:00–04:00, 23:00–24:00 Jun 23 07:00–09:00 Jun 24 07:00–10:00, 23:00–24:00 Jun 25 00:00–10:00 Jun 26 00:00–05:00, 07:00–09:00 Jun 27 00:00–09:00 Jun 28 18:00–24:00 Jun 29 00:00–03:00, 22:00–24:00 Jun 30 00:00–06:00
July
Jul 1 00:00–09:00, 23:00–24:00 Jul 2 00:00–09:00, 23:00–24:00 Jul 3 00:00–10:00 Jul 4 01:00–10:00, 23:00–24:00 Jul 5 00:00–04:00, 19:00–24:00 Jul 6 00:00–02:00 Jul 7 00:00–09:00, 23:00–24:00 Jul 8 00:00–08:00 Jul 9 01:00–09:00 Jul 10 01:00–10:00 Jul 11 01:00–09:00, 21:00–24:00 Jul 12 00:00–03:00, 18:00–24:00 Jul 13 00:00–02:00 Jul 14 23:00–24:00 Jul 15 00:00–09:00 Jul 16 00:00–09:00 Jul 17 00:00–09:00 Jul 18 01:00–10:00 Jul 19 18:00–24:00 Jul 20 00:00–01:00, 20:00–24:00 Jul 21 00:00–03:00 Jul 22 00:00–09:00 Jul 23 00:00–09:00 Jul 24 01:00–02:00, 05:00–09:00 Jul 25 02:00–07:00 Jul 26 19:00–24:00 Jul 27 00:00–02:00