Most often in January, 28 days.
Highest follower count seen that year: 15,985.
January
Jan 1 23:00–24:00 Jan 2 00:00–01:00, 22:00–23:00 Jan 3 02:00–03:00 Jan 5 00:00–05:00, 21:00–23:00 Jan 7 02:00–04:00 Jan 8 00:00–04:00 Jan 9 00:00–02:00 Jan 10 01:00–02:00 Jan 11 00:00–02:00 Jan 13 00:00–04:00, 22:00–23:00 Jan 14 02:00–05:00, 23:00–24:00 Jan 15 00:00–04:00 Jan 16 01:00–04:00, 23:00–24:00 Jan 17 00:00–03:00 Jan 18 23:00–24:00 Jan 19 00:00–02:00, 23:00–24:00 Jan 20 00:00–02:00, 23:00–24:00 Jan 21 00:00–03:00, 23:00–24:00 Jan 22 02:00–06:00, 21:00–23:00 Jan 23 02:00–06:00 Jan 24 02:00–03:00 Jan 25 01:00–06:00, 23:00–24:00 Jan 26 00:00–01:00, 03:00–05:00, 23:00–24:00 Jan 27 00:00–01:00, 03:00–04:00, 23:00–24:00 Jan 28 22:00–24:00 Jan 29 00:00–06:00, 22:00–24:00 Jan 30 02:00–05:00, 23:00–24:00 Jan 31 00:00–03:00
February
Feb 2 00:00–06:00, 23:00–24:00 Feb 3 00:00–04:00, 23:00–24:00 Feb 4 00:00–06:00, 21:00–24:00 Feb 5 01:00–06:00, 22:00–24:00 Feb 6 01:00–06:00 Feb 7 02:00–05:00 Feb 8 02:00–03:00 Feb 9 01:00–04:00, 23:00–24:00 Feb 10 00:00–01:00, 23:00–24:00 Feb 11 00:00–01:00 Feb 12 02:00–05:00, 22:00–24:00 Feb 13 00:00–03:00, 19:00–21:00, 23:00–24:00 Feb 14 00:00–05:00 Feb 15 01:00–02:00, 04:00–06:00, 23:00–24:00 Feb 16 00:00–06:00, 23:00–24:00 Feb 17 01:00–03:00 Feb 19 00:00–02:00, 23:00–24:00 Feb 20 02:00–04:00 Feb 21 01:00–02:00 Feb 22 02:00–04:00 Feb 23 00:00–03:00 Feb 24 00:00–04:00, 21:00–22:00 Feb 25 00:00–01:00, 22:00–24:00 Feb 26 00:00–03:00 Feb 27 00:00–06:00 Feb 28 00:00–03:00
March
Mar 1 01:00–02:00 Mar 16 18:00–21:00 Mar 22 13:00–17:00 Mar 23 09:00–10:00 Mar 24 21:00–22:00 Mar 25 21:00–23:00 Mar 26 22:00–23:00 Mar 27 14:00–16:00, 21:00–23:00 Mar 28 13:00–16:00, 21:00–24:00 Mar 29 11:00–12:00, 15:00–16:00
April
Apr 1 00:00–03:00, 22:00–24:00 Apr 2 00:00–01:00, 20:00–23:00 Apr 3 15:00–16:00, 23:00–24:00 Apr 4 00:00–01:00, 17:00–18:00 Apr 5 03:00–04:00, 20:00–22:00 Apr 6 00:00–02:00, 23:00–24:00 Apr 7 21:00–23:00 Apr 9 00:00–02:00, 21:00–22:00 Apr 10 22:00–24:00 Apr 12 22:00–24:00 Apr 13 23:00–24:00 Apr 14 00:00–01:00, 20:00–21:00 Apr 15 21:00–23:00 Apr 17 21:00–24:00 Apr 18 00:00–01:00 Apr 20 22:00–24:00 Apr 21 00:00–02:00, 22:00–24:00 Apr 22 00:00–03:00, 23:00–24:00 Apr 23 00:00–02:00, 20:00–23:00 Apr 24 02:00–04:00, 23:00–24:00 Apr 25 00:00–01:00, 22:00–24:00 Apr 27 00:00–02:00 Apr 29 00:00–04:00, 22:00–24:00 Apr 30 23:00–24:00
May
May 1 00:00–01:00, 23:00–24:00 May 5 23:00–24:00 May 6 23:00–24:00 May 7 00:00–04:00, 21:00–22:00 May 8 01:00–02:00, 22:00–24:00 May 9 00:00–01:00 May 10 00:00–04:00, 23:00–24:00 May 11 00:00–05:00, 23:00–24:00 May 12 00:00–01:00, 22:00–24:00 May 13 23:00–24:00 May 14 00:00–01:00 May 15 02:00–03:00, 23:00–24:00 May 16 00:00–01:00 May 17 00:00–01:00, 22:00–24:00 May 18 22:00–24:00 May 19 22:00–24:00 May 20 23:00–24:00 May 21 21:00–22:00 May 22 00:00–02:00, 22:00–24:00 May 23 00:00–01:00 May 24 01:00–02:00, 20:00–23:00 May 25 01:00–02:00, 22:00–24:00 May 26 00:00–01:00, 21:00–24:00 May 27 00:00–02:00 May 28 00:00–02:00, 22:00–23:00 May 29 00:00–02:00 May 30 02:00–03:00 May 31 00:00–03:00, 22:00–23:00
June
Jun 1 02:00–03:00, 22:00–24:00 Jun 2 00:00–01:00, 23:00–24:00 Jun 3 00:00–02:00, 20:00–22:00 Jun 4 00:00–02:00, 22:00–24:00 Jun 5 00:00–02:00 Jun 8 23:00–24:00 Jun 9 00:00–01:00, 23:00–24:00 Jun 10 00:00–01:00, 22:00–24:00 Jun 11 00:00–01:00, 23:00–24:00 Jun 13 01:00–02:00 Jun 14 00:00–03:00, 22:00–24:00 Jun 15 00:00–01:00, 23:00–24:00 Jun 16 00:00–02:00, 23:00–24:00 Jun 17 00:00–02:00, 23:00–24:00 Jun 18 00:00–02:00 Jun 20 00:00–02:00 Jun 21 00:00–02:00, 22:00–24:00 Jun 22 00:00–02:00, 23:00–24:00 Jun 23 00:00–01:00, 23:00–24:00 Jun 24 00:00–01:00, 23:00–24:00 Jun 25 00:00–02:00, 20:00–22:00 Jun 26 22:00–24:00 Jun 27 00:00–01:00, 22:00–24:00 Jun 29 21:00–23:00
July
Jul 1 00:00–02:00 Jul 3 22:00–24:00 Jul 4 00:00–01:00 Jul 6 21:00–23:00 Jul 7 23:00–24:00 Jul 8 23:00–24:00 Jul 9 00:00–02:00, 21:00–23:00 Jul 10 23:00–24:00 Jul 11 00:00–02:00 Jul 12 00:00–01:00, 23:00–24:00 Jul 13 00:00–02:00 Jul 14 00:00–02:00, 22:00–24:00 Jul 15 00:00–03:00, 21:00–23:00 Jul 16 00:00–02:00, 23:00–24:00 Jul 17 00:00–01:00, 19:00–21:00, 23:00–24:00 Jul 18 02:00–03:00 Jul 19 00:00–03:00 Jul 20 00:00–02:00, 21:00–23:00 Jul 21 00:00–01:00, 22:00–24:00 Jul 22 00:00–03:00, 23:00–24:00 Jul 23 00:00–01:00 Jul 24 22:00–24:00 Jul 25 20:00–23:00 Jul 26 00:00–01:00, 23:00–24:00 Jul 27 22:00–24:00 Jul 28 22:00–24:00 Jul 29 21:00–22:00
August
Aug 5 22:00–23:00 Aug 10 21:00–22:00 Aug 12 20:00–22:00 Aug 16 22:00–23:00 Aug 17 21:00–23:00 Aug 18 20:00–22:00 Aug 20 21:00–23:00 Aug 21 00:00–01:00, 23:00–24:00 Aug 24 18:00–20:00 Aug 26 19:00–21:00 Aug 28 21:00–24:00 Aug 29 01:00–02:00, 17:00–18:00 Aug 30 00:00–02:00, 22:00–24:00 Aug 31 20:00–22:00
September
Sep 2 20:00–23:00 Sep 7 20:00–21:00 Sep 9 23:00–24:00 Sep 10 00:00–01:00 Sep 11 20:00–23:00 Sep 13 17:00–19:00, 22:00–24:00 Sep 16 23:00–24:00 Sep 17 00:00–02:00, 23:00–24:00 Sep 18 00:00–01:00
October
Oct 21 01:00–03:00, 23:00–24:00 Oct 22 00:00–02:00 Oct 24 21:00–23:00 Oct 26 00:00–01:00 Oct 27 00:00–02:00 Oct 28 00:00–01:00, 23:00–24:00 Oct 29 00:00–02:00, 23:00–24:00 Oct 30 00:00–01:00, 22:00–24:00 Oct 31 22:00–23:00
November
Nov 1 20:00–23:00 Nov 3 00:00–02:00 Nov 4 00:00–03:00, 23:00–24:00 Nov 5 23:00–24:00 Nov 6 00:00–02:00, 23:00–24:00 Nov 7 00:00–01:00, 23:00–24:00 Nov 8 00:00–02:00, 22:00–24:00 Nov 9 23:00–24:00 Nov 10 22:00–24:00 Nov 11 00:00–01:00, 23:00–24:00 Nov 12 00:00–01:00 Nov 13 00:00–02:00, 23:00–24:00 Nov 15 01:00–03:00, 23:00–24:00 Nov 16 02:00–03:00 Nov 17 01:00–03:00 Nov 23 00:00–02:00 Nov 24 23:00–24:00 Nov 25 00:00–02:00 Nov 27 01:00–02:00 Nov 28 00:00–01:00 Nov 29 00:00–01:00 Nov 30 19:00–21:00
December
Dec 1 01:00–03:00 Dec 2 00:00–01:00, 21:00–24:00 Dec 5 00:00–01:00 Dec 6 00:00–02:00 Dec 7 00:00–02:00 Dec 8 00:00–02:00, 23:00–24:00 Dec 9 00:00–01:00 Dec 10 00:00–02:00 Dec 11 00:00–02:00, 23:00–24:00 Dec 12 00:00–03:00 Dec 13 03:00–04:00 Dec 14 01:00–02:00, 23:00–24:00 Dec 15 00:00–01:00 Dec 16 00:00–03:00 Dec 17 00:00–01:00 Dec 18 01:00–02:00, 22:00–24:00 Dec 19 00:00–02:00 Dec 21 00:00–03:00 Dec 22 00:00–01:00 Dec 23 00:00–02:00 Dec 24 01:00–02:00 Dec 27 01:00–03:00 Dec 28 00:00–02:00 Dec 29 01:00–02:00, 22:00–23:00 Dec 30 00:00–01:00