Most often in May, 28 days.
Highest follower count seen that year: 27,767.
January
Jan 1 19:00–22:00 Jan 2 17:00–21:00 Jan 6 17:00–20:00 Jan 7 20:00–22:00 Jan 11 17:00–20:00 Jan 26 18:00–20:00
February
Feb 3 17:00–20:00 Feb 12 20:00–22:00 Feb 16 15:00–17:00 Feb 23 18:00–20:00
March
Mar 3 17:00–19:00 Mar 9 20:00–21:00 Mar 14 16:00–18:00 Mar 15 20:00–22:00 Mar 20 11:00–14:00 Mar 21 09:00–12:00 Mar 22 09:00–12:00 Mar 23 13:00–16:00 Mar 24 10:00–14:00 Mar 25 10:00–14:00 Mar 26 10:00–15:00 Mar 27 10:00–12:00, 16:00–18:00 Mar 28 07:00–13:00 Mar 29 09:00–13:00 Mar 30 07:00–11:00 Mar 31 11:00–15:00
April
Apr 1 11:00–17:00 Apr 2 15:00–17:00 Apr 5 10:00–14:00 Apr 6 20:00–22:00 Apr 7 10:00–15:00 Apr 8 11:00–17:00 Apr 9 12:00–15:00, 20:00–21:00 Apr 10 15:00–20:00 Apr 11 14:00–19:00 Apr 12 11:00–15:00 Apr 14 15:00–19:00 Apr 15 09:00–13:00 Apr 16 13:00–16:00 Apr 17 11:00–15:00 Apr 18 08:00–12:00, 16:00–19:00 Apr 19 10:00–12:00, 21:00–22:00 Apr 20 12:00–16:00 Apr 21 12:00–13:00 Apr 22 08:00–12:00 Apr 23 18:00–20:00 Apr 24 09:00–13:00 Apr 25 10:00–12:00, 18:00–20:00 Apr 26 10:00–12:00 Apr 27 10:00–14:00 Apr 28 11:00–13:00 Apr 29 09:00–11:00, 15:00–20:00 Apr 30 10:00–18:00, 22:00–24:00
May
May 1 10:00–14:00, 19:00–23:00 May 2 09:00–12:00 May 3 09:00–14:00, 16:00–17:00 May 4 10:00–13:00, 19:00–21:00 May 5 08:00–11:00, 16:00–19:00 May 6 11:00–16:00 May 8 04:00–07:00 May 9 09:00–12:00 May 10 05:00–09:00, 15:00–17:00, 20:00–22:00 May 11 10:00–15:00 May 12 11:00–15:00 May 13 08:00–10:00 May 14 13:00–18:00 May 15 08:00–12:00 May 16 07:00–11:00, 16:00–20:00 May 17 05:00–11:00, 17:00–21:00 May 18 06:00–10:00, 17:00–19:00 May 19 04:00–08:00 May 20 05:00–09:00 May 21 07:00–09:00 May 22 17:00–19:00 May 25 09:00–13:00 May 26 16:00–20:00 May 27 03:00–06:00 May 28 07:00–10:00, 20:00–22:00 May 29 11:00–15:00 May 30 12:00–15:00 May 31 07:00–08:00
June
Jun 1 13:00–17:00 Jun 2 07:00–13:00 Jun 3 06:00–10:00 Jun 4 07:00–11:00 Jun 6 09:00–14:00 Jun 7 22:00–23:00 Jun 8 09:00–13:00 Jun 9 14:00–16:00 Jun 11 10:00–12:00 Jun 13 13:00–17:00 Jun 14 10:00–13:00 Jun 15 10:00–17:00 Jun 16 10:00–12:00 Jun 17 16:00–19:00 Jun 18 11:00–16:00 Jun 19 10:00–14:00 Jun 20 03:00–06:00, 16:00–17:00 Jun 21 10:00–13:00 Jun 22 10:00–12:00 Jun 24 07:00–10:00 Jun 25 02:00–05:00 Jun 26 06:00–09:00 Jun 28 20:00–21:00 Jun 30 13:00–15:00
July
Jul 1 08:00–10:00 Jul 2 11:00–14:00 Jul 3 00:00–01:00, 15:00–18:00 Jul 5 09:00–12:00 Jul 7 21:00–22:00 Jul 10 10:00–14:00 Jul 11 06:00–09:00 Jul 12 10:00–12:00 Jul 13 09:00–11:00 Jul 14 10:00–13:00 Jul 15 09:00–11:00 Jul 16 09:00–11:00 Jul 19 09:00–11:00 Jul 20 10:00–12:00 Jul 21 11:00–13:00 Jul 22 10:00–13:00 Jul 23 07:00–10:00, 12:00–13:00 Jul 24 08:00–14:00 Jul 25 08:00–10:00 Jul 26 10:00–12:00 Jul 27 05:00–07:00 Jul 28 08:00–11:00 Jul 29 13:00–15:00 Jul 30 15:00–17:00 Jul 31 08:00–10:00
August
Aug 1 21:00–23:00 Aug 2 05:00–07:00, 16:00–18:00 Aug 3 10:00–12:00 Aug 4 17:00–20:00 Aug 5 10:00–12:00 Aug 6 09:00–10:00, 22:00–24:00 Aug 7 16:00–17:00, 19:00–21:00 Aug 8 11:00–12:00 Aug 10 12:00–14:00 Aug 11 16:00–18:00 Aug 12 09:00–12:00 Aug 13 09:00–11:00, 18:00–21:00 Aug 14 09:00–11:00 Aug 16 19:00–23:00 Aug 17 11:00–12:00 Aug 18 19:00–21:00 Aug 19 21:00–23:00 Aug 20 21:00–23:00 Aug 21 09:00–11:00 Aug 22 19:00–21:00 Aug 23 10:00–13:00 Aug 24 19:00–21:00 Aug 25 10:00–13:00 Aug 26 19:00–23:00 Aug 27 10:00–12:00 Aug 29 19:00–21:00 Aug 31 21:00–23:00
September
Sep 2 11:00–14:00 Sep 3 11:00–12:00 Sep 4 11:00–16:00 Sep 5 10:00–14:00 Sep 6 15:00–16:00 Sep 7 09:00–10:00 Sep 8 11:00–13:00 Sep 9 09:00–10:00 Sep 10 08:00–09:00 Sep 11 09:00–11:00 Sep 12 07:00–08:00 Sep 13 07:00–09:00 Sep 15 09:00–12:00 Sep 16 10:00–14:00 Sep 17 06:00–10:00 Sep 18 21:00–23:00 Sep 19 09:00–10:00 Sep 20 03:00–06:00 Sep 21 11:00–13:00 Sep 22 09:00–11:00 Sep 23 09:00–11:00 Sep 24 19:00–22:00 Sep 25 07:00–10:00, 21:00–23:00 Sep 27 09:00–13:00 Sep 28 10:00–13:00 Sep 29 03:00–06:00 Sep 30 03:00–07:00, 20:00–22:00
October
Oct 2 07:00–08:00 Oct 3 07:00–09:00 Oct 4 21:00–23:00 Oct 5 12:00–15:00 Oct 6 10:00–12:00 Oct 7 09:00–13:00 Oct 11 10:00–16:00 Oct 12 14:00–17:00 Oct 13 09:00–12:00 Oct 15 06:00–09:00, 22:00–24:00 Oct 20 11:00–15:00 Oct 21 13:00–16:00 Oct 22 16:00–19:00 Oct 23 21:00–24:00 Oct 24 12:00–17:00 Oct 25 10:00–13:00