Most often in April, 29 days.
Highest follower count seen that year: 256,348.
January
Jan 5 19:00–22:00 Jan 6 01:00–06:00, 20:00–22:00 Jan 7 00:00–06:00 Jan 9 19:00–24:00 Jan 10 00:00–04:00, 19:00–24:00 Jan 11 00:00–04:00, 19:00–23:00 Jan 12 00:00–05:00, 20:00–24:00 Jan 13 00:00–05:00 Jan 14 22:00–24:00 Jan 15 00:00–05:00, 22:00–24:00 Jan 16 00:00–05:00 Jan 17 22:00–24:00 Jan 18 00:00–05:00, 20:00–24:00 Jan 19 00:00–04:00, 22:00–24:00 Jan 20 00:00–06:00 Jan 21 22:00–24:00 Jan 22 00:00–06:00, 22:00–24:00 Jan 23 00:00–05:00 Jan 24 22:00–24:00 Jan 25 00:00–05:00, 20:00–24:00 Jan 26 00:00–04:00, 22:00–24:00 Jan 27 00:00–06:00, 22:00–24:00 Jan 28 00:00–06:00, 21:00–24:00 Jan 29 00:00–05:00 Jan 31 22:00–24:00
February
Feb 1 00:00–07:00, 20:00–24:00 Feb 2 00:00–04:00, 22:00–24:00 Feb 3 00:00–06:00 Feb 4 22:00–24:00 Feb 5 00:00–06:00, 22:00–24:00 Feb 6 00:00–05:00, 22:00–24:00 Feb 7 00:00–05:00 Feb 8 20:00–24:00 Feb 9 00:00–05:00, 22:00–24:00 Feb 10 00:00–05:00 Feb 11 22:00–24:00 Feb 12 00:00–04:00, 22:00–24:00 Feb 13 00:00–05:00, 22:00–24:00 Feb 14 00:00–06:00, 20:00–24:00 Feb 15 00:00–04:00 Feb 16 22:00–24:00 Feb 17 00:00–05:00 Feb 18 22:00–24:00 Feb 19 00:00–05:00, 22:00–24:00 Feb 20 00:00–05:00 Feb 21 22:00–24:00 Feb 22 00:00–06:00, 20:00–24:00 Feb 23 00:00–05:00, 22:00–24:00 Feb 24 00:00–06:00, 22:00–24:00 Feb 25 00:00–05:00, 22:00–24:00 Feb 26 00:00–05:00 Feb 28 22:00–24:00
March
Mar 1 00:00–06:00, 20:00–24:00 Mar 2 00:00–05:00, 22:00–24:00 Mar 3 00:00–05:00 Mar 4 22:00–24:00 Mar 5 00:00–05:00, 22:00–24:00 Mar 6 00:00–06:00, 22:00–24:00 Mar 7 00:00–07:00 Mar 8 20:00–24:00 Mar 9 00:00–01:00, 22:00–24:00 Mar 10 00:00–05:00, 22:00–24:00 Mar 11 00:00–05:00, 22:00–24:00 Mar 12 00:00–06:00, 22:00–24:00 Mar 13 00:00–05:00 Mar 16 22:00–24:00 Mar 17 00:00–05:00 Mar 18 22:00–24:00 Mar 19 00:00–05:00, 22:00–24:00 Mar 20 00:00–05:00, 22:00–24:00 Mar 21 00:00–06:00 Mar 22 22:00–24:00 Mar 23 00:00–06:00, 20:00–24:00 Mar 24 00:00–05:00, 22:00–24:00 Mar 25 00:00–06:00 Mar 28 22:00–24:00 Mar 29 00:00–06:00, 20:00–24:00 Mar 30 00:00–05:00, 22:00–24:00 Mar 31 00:00–06:00
April
Apr 1 22:00–24:00 Apr 2 00:00–06:00, 22:00–24:00 Apr 3 00:00–05:00, 22:00–24:00 Apr 4 00:00–06:00 Apr 5 20:00–24:00 Apr 6 00:00–05:00, 22:00–24:00 Apr 7 00:00–05:00, 22:00–24:00 Apr 8 00:00–05:00 Apr 9 22:00–24:00 Apr 10 00:00–05:00 Apr 12 20:00–24:00 Apr 13 00:00–04:00, 22:00–24:00 Apr 14 00:00–05:00 Apr 15 22:00–24:00 Apr 16 00:00–05:00 Apr 17 22:00–24:00 Apr 18 00:00–05:00, 22:00–24:00 Apr 19 00:00–05:00, 21:00–24:00 Apr 20 01:00–02:00, 22:00–24:00 Apr 21 00:00–05:00 Apr 22 22:00–24:00 Apr 23 00:00–05:00, 22:00–24:00 Apr 24 00:00–05:00, 22:00–24:00 Apr 25 00:00–05:00 Apr 26 20:00–24:00 Apr 27 00:00–05:00, 22:00–24:00 Apr 28 00:00–05:00, 22:00–24:00 Apr 29 00:00–06:00, 22:00–24:00 Apr 30 00:00–05:00
May
May 1 22:00–24:00 May 2 00:00–05:00 May 4 22:00–24:00 May 5 00:00–06:00, 22:00–24:00 May 6 00:00–06:00, 22:00–24:00 May 7 00:00–05:00 May 8 22:00–24:00 May 9 00:00–05:00 May 10 22:00–24:00 May 11 00:00–06:00, 20:00–24:00 May 12 00:00–05:00 May 13 22:00–24:00 May 14 00:00–05:00, 22:00–24:00 May 15 00:00–06:00, 22:00–24:00 May 16 00:00–06:00 May 17 22:00–24:00 May 18 00:00–05:00, 20:00–24:00 May 19 00:00–05:00 May 24 22:00–24:00 May 25 00:00–06:00, 20:00–24:00 May 26 00:00–06:00, 22:00–24:00 May 27 00:00–06:00 May 28 22:00–24:00 May 29 00:00–06:00, 22:00–24:00 May 30 00:00–05:00 May 31 22:00–24:00
June
Jun 1 00:00–05:00, 20:00–24:00 Jun 2 00:00–04:00 Jun 3 22:00–24:00 Jun 4 00:00–05:00, 22:00–24:00 Jun 5 00:00–04:00 Jun 7 22:00–24:00 Jun 8 00:00–03:00, 20:00–24:00 Jun 9 00:00–04:00 Jun 10 22:00–24:00 Jun 11 00:00–05:00, 22:00–24:00 Jun 12 00:00–06:00, 22:00–24:00 Jun 13 00:00–05:00 Jun 14 22:00–24:00 Jun 15 00:00–06:00, 20:00–24:00 Jun 16 00:00–04:00, 22:00–24:00 Jun 17 00:00–07:00, 22:00–24:00 Jun 18 00:00–05:00 Jun 20 22:00–24:00 Jun 21 00:00–05:00, 22:00–24:00 Jun 22 00:00–05:00, 20:00–24:00 Jun 23 00:00–05:00 Jun 24 22:00–24:00 Jun 25 00:00–05:00, 22:00–24:00 Jun 26 00:00–05:00 Jun 27 22:00–24:00 Jun 28 00:00–06:00, 22:00–24:00 Jun 29 00:00–05:00, 21:00–24:00 Jun 30 00:00–05:00, 22:00–24:00
July
Jul 1 00:00–05:00, 22:00–24:00 Jul 2 00:00–07:00 Jul 4 22:00–24:00 Jul 5 00:00–05:00, 22:00–24:00 Jul 6 00:00–06:00, 20:00–24:00 Jul 7 00:00–05:00, 22:00–24:00 Jul 8 00:00–05:00 Jul 10 07:00–15:00 Jul 11 07:00–16:00 Jul 12 08:00–16:00 Jul 13 07:00–15:00 Jul 17 07:00–16:00 Jul 18 07:00–14:00 Jul 19 07:00–15:00 Jul 20 07:00–15:00 Jul 22 07:00–16:00 Jul 23 07:00–16:00 Jul 24 07:00–15:00 Jul 25 07:00–15:00 Jul 26 07:00–16:00 Jul 27 07:00–16:00 Jul 28 07:00–16:00 Jul 31 08:00–16:00
August
Aug 1 07:00–15:00 Aug 2 08:00–16:00 Aug 3 08:00–17:00 Aug 4 07:00–16:00 Aug 7 07:00–16:00 Aug 8 07:00–15:00 Aug 9 07:00–16:00 Aug 10 07:00–15:00 Aug 11 08:00–16:00 Aug 14 08:00–17:00 Aug 15 06:00–15:00 Aug 16 09:00–17:00 Aug 17 07:00–16:00 Aug 18 08:00–16:00 Aug 21 07:00–15:00 Aug 22 10:00–17:00 Aug 23 07:00–15:00 Aug 24 07:00–15:00 Aug 25 07:00–16:00 Aug 28 07:00–15:00 Aug 29 07:00–15:00 Aug 30 07:00–16:00 Aug 31 07:00–15:00
September
Sep 1 07:00–15:00 Sep 5 08:00–16:00 Sep 6 07:00–15:00 Sep 7 07:00–15:00 Sep 9 07:00–16:00 Sep 10 07:00–15:00 Sep 11 07:00–16:00 Sep 12 08:00–16:00 Sep 13 07:00–15:00 Sep 14 07:00–16:00 Sep 15 07:00–15:00 Sep 17 08:00–16:00 Sep 18 07:00–16:00 Sep 20 07:00–15:00 Sep 21 07:00–16:00 Sep 22 07:00–16:00 Sep 26 07:00–16:00 Sep 27 07:00–16:00 Sep 28 07:00–15:00 Sep 29 07:00–17:00
October
Oct 2 07:00–16:00 Oct 3 07:00–16:00 Oct 4 07:00–16:00 Oct 5 07:00–16:00 Oct 6 07:00–16:00 Oct 8 08:00–16:00 Oct 9 08:00–17:00 Oct 11 08:00–17:00 Oct 12 07:00–15:00 Oct 13 07:00–16:00 Oct 16 07:00–16:00 Oct 17 08:00–16:00 Oct 18 08:00–17:00 Oct 19 07:00–16:00 Oct 20 08:00–16:00 Oct 22 08:00–17:00 Oct 24 07:00–15:00 Oct 25 08:00–16:00 Oct 26 07:00–16:00 Oct 27 08:00–17:00 Oct 31 08:00–17:00
November
Nov 1 08:00–17:00 Nov 2 09:00–16:00 Nov 3 08:00–17:00 Nov 4 06:00–14:00 Nov 6 08:00–17:00 Nov 7 08:00–17:00 Nov 8 08:00–16:00 Nov 9 08:00–16:00 Nov 10 08:00–16:00 Nov 13 09:00–17:00 Nov 14 08:00–16:00 Nov 15 13:00–18:00 Nov 16 08:00–16:00 Nov 17 08:00–11:00 Nov 19 10:00–19:00 Nov 20 09:00–18:00 Nov 21 08:00–17:00 Nov 22 08:00–16:00 Nov 23 10:00–19:00 Nov 29 10:00–18:00 Nov 30 08:00–17:00
December
Dec 1 08:00–15:00 Dec 4 08:00–16:00 Dec 5 08:00–17:00 Dec 6 08:00–17:00 Dec 7 09:00–17:00 Dec 8 08:00–17:00 Dec 11 08:00–17:00 Dec 12 09:00–17:00 Dec 13 08:00–16:00 Dec 14 09:00–18:00 Dec 17 09:00–19:00 Dec 18 09:00–16:00 Dec 19 09:00–18:00 Dec 20 09:00–11:00, 14:00–18:00 Dec 21 08:00–17:00 Dec 22 10:00–19:00 Dec 25 09:00–18:00 Dec 26 09:00–18:00 Dec 27 10:00–19:00 Dec 28 09:00–17:00 Dec 29 06:00–13:00