Most often in October, 21 days.
Highest follower count seen that year: 12,871.
January
Jan 9 23:00–24:00 Jan 10 00:00–04:00, 22:00–24:00 Jan 11 00:00–04:00 Jan 14 23:00–24:00 Jan 15 00:00–03:00, 22:00–24:00 Jan 16 00:00–03:00 Jan 17 22:00–24:00 Jan 18 00:00–03:00, 22:00–24:00 Jan 19 00:00–04:00 Jan 22 00:00–03:00, 23:00–24:00 Jan 23 00:00–03:00 Jan 25 00:00–04:00, 23:00–24:00 Jan 26 00:00–04:00 Jan 28 23:00–24:00 Jan 29 00:00–02:00, 23:00–24:00 Jan 30 00:00–03:00 Jan 31 23:00–24:00
February
Feb 1 00:00–02:00 Feb 6 21:00–24:00 Feb 7 00:00–03:00, 21:00–24:00 Feb 8 00:00–04:00 Feb 10 23:00–24:00 Feb 11 00:00–03:00 Feb 12 23:00–24:00 Feb 13 00:00–03:00, 21:00–24:00 Feb 14 00:00–01:00 Feb 27 23:00–24:00 Feb 28 20:00–24:00
March
Mar 1 21:00–24:00 Mar 2 00:00–02:00 Mar 5 21:00–22:00 Mar 6 00:00–01:00, 20:00–24:00 Mar 7 00:00–01:00, 20:00–24:00 Mar 8 00:00–01:00 Mar 12 20:00–24:00 Mar 13 20:00–24:00 Mar 14 00:00–01:00, 20:00–23:00 Mar 15 00:00–02:00, 22:00–24:00 Mar 18 20:00–24:00 Mar 19 21:00–24:00 Mar 20 19:00–24:00 Mar 25 21:00–23:00 Mar 26 00:00–02:00 Mar 27 20:00–24:00 Mar 28 00:00–01:00 Mar 29 19:00–24:00 Mar 30 00:00–01:00
April
Apr 1 19:00–24:00 Apr 2 00:00–01:00, 19:00–24:00 Apr 7 20:00–24:00 Apr 8 00:00–01:00, 20:00–24:00 Apr 9 00:00–01:00 Apr 15 21:00–23:00 Apr 16 22:00–24:00 Apr 17 00:00–01:00, 22:00–24:00 Apr 18 00:00–02:00, 21:00–24:00 Apr 19 00:00–01:00 Apr 24 22:00–24:00 Apr 25 00:00–02:00, 21:00–24:00 Apr 26 00:00–01:00, 21:00–22:00 Apr 27 00:00–04:00 Apr 28 19:00–24:00 Apr 29 00:00–01:00, 21:00–23:00
May
May 1 20:00–23:00 May 6 18:00–24:00 May 7 19:00–22:00 May 8 01:00–03:00, 20:00–24:00 May 12 19:00–22:00 May 13 19:00–22:00 May 15 19:00–21:00, 23:00–24:00 May 16 00:00–02:00, 20:00–23:00 May 17 00:00–01:00 May 19 18:00–24:00 May 20 19:00–23:00 May 22 18:00–22:00 May 27 21:00–24:00 May 28 20:00–23:00 May 29 19:00–23:00
June
Jun 3 17:00–24:00 Jun 4 00:00–01:00, 18:00–22:00 Jun 5 19:00–24:00 Jun 7 16:00–19:00 Jun 9 20:00–24:00 Jun 10 00:00–01:00, 19:00–22:00 Jun 12 20:00–23:00 Jun 13 20:00–23:00 Jun 14 00:00–02:00, 19:00–24:00 Jun 17 19:00–24:00 Jun 18 19:00–23:00 Jun 19 18:00–22:00 Jun 23 16:00–23:00 Jun 25 16:00–20:00, 22:00–24:00 Jun 26 00:00–02:00, 19:00–24:00 Jun 27 00:00–02:00, 20:00–23:00 Jun 28 00:00–03:00
July
Jul 1 03:00–05:00, 18:00–24:00 Jul 2 18:00–23:00 Jul 3 02:00–04:00, 19:00–24:00 Jul 4 01:00–02:00, 20:00–24:00 Jul 5 00:00–04:00 Jul 7 03:00–04:00, 18:00–24:00 Jul 8 00:00–01:00, 19:00–24:00 Jul 14 18:00–24:00 Jul 15 17:00–24:00 Jul 16 20:00–24:00 Jul 17 00:00–01:00, 18:00–24:00 Jul 22 19:00–22:00 Jul 23 18:00–24:00 Jul 24 00:00–01:00, 19:00–24:00 Jul 25 19:00–24:00 Jul 27 19:00–23:00 Jul 28 19:00–24:00 Jul 29 00:00–01:00, 19:00–24:00 Jul 30 00:00–02:00 Jul 31 19:00–24:00
August
Aug 1 17:00–23:00 Aug 4 18:00–21:00 Aug 5 19:00–24:00 Aug 6 00:00–01:00, 19:00–20:00 Aug 7 19:00–22:00 Aug 13 17:00–19:00 Aug 14 18:00–23:00 Aug 15 19:00–21:00 Aug 16 01:00–03:00 Aug 19 20:00–23:00 Aug 20 00:00–01:00, 19:00–24:00 Aug 21 00:00–02:00 Aug 25 23:00–24:00 Aug 26 00:00–04:00, 22:00–24:00 Aug 27 00:00–04:00, 23:00–24:00 Aug 28 00:00–02:00, 23:00–24:00 Aug 29 00:00–04:00 Aug 30 17:00–20:00
September
Sep 1 23:00–24:00 Sep 2 00:00–02:00 Sep 3 21:00–24:00 Sep 4 01:00–03:00, 21:00–24:00 Sep 5 00:00–01:00 Sep 8 23:00–24:00 Sep 9 00:00–03:00, 21:00–24:00 Sep 10 00:00–02:00, 22:00–24:00 Sep 11 00:00–02:00 Sep 12 22:00–24:00 Sep 13 00:00–04:00, 21:00–23:00 Sep 15 22:00–24:00 Sep 16 00:00–05:00, 22:00–24:00 Sep 22 23:00–24:00 Sep 23 00:00–03:00, 23:00–24:00 Sep 24 00:00–06:00 Sep 25 00:00–03:00, 23:00–24:00 Sep 26 00:00–05:00, 23:00–24:00 Sep 27 00:00–05:00
October
Oct 1 18:00–22:00 Oct 2 00:00–02:00, 23:00–24:00 Oct 3 00:00–04:00, 23:00–24:00 Oct 4 00:00–04:00 Oct 5 00:00–05:00 Oct 7 00:00–05:00, 23:00–24:00 Oct 8 00:00–05:00 Oct 10 01:00–04:00, 07:00–08:00 Oct 11 00:00–06:00 Oct 12 01:00–06:00 Oct 14 22:00–24:00 Oct 15 00:00–04:00, 23:00–24:00 Oct 16 00:00–03:00 Oct 20 03:00–07:00 Oct 21 00:00–03:00 Oct 22 00:00–05:00 Oct 23 00:00–05:00 Oct 25 00:00–05:00 Oct 26 01:00–06:00 Oct 28 00:00–04:00, 22:00–24:00 Oct 29 00:00–04:00
November
Nov 2 02:00–07:00 Nov 3 03:00–06:00 Nov 5 01:00–07:00 Nov 10 02:00–04:00 Nov 12 00:00–04:00 Nov 14 00:00–04:00 Nov 16 00:00–06:00 Nov 18 01:00–04:00 Nov 20 01:00–05:00 Nov 25 01:00–07:00 Nov 26 23:00–24:00 Nov 27 00:00–02:00
December
Dec 1 23:00–24:00 Dec 2 00:00–03:00 Dec 4 01:00–05:00