Most often in April, 28 days.
Highest follower count seen that year: 223,204.
January
Jan 1 03:00–10:00, 15:00–24:00 Jan 2 00:00–10:00 Jan 4 01:00–10:00 Jan 5 01:00–10:00, 16:00–24:00 Jan 6 00:00–01:00, 16:00–24:00 Jan 7 00:00–10:00 Jan 8 01:00–10:00, 15:00–24:00 Jan 9 00:00–01:00, 16:00–24:00 Jan 10 00:00–10:00 Jan 11 01:00–10:00 Jan 12 01:00–10:00 Jan 13 15:00–24:00 Jan 14 00:00–01:00 Jan 16 01:00–10:00 Jan 17 01:00–10:00 Jan 18 01:00–10:00 Jan 20 01:00–10:00 Jan 21 01:00–10:00 Jan 22 01:00–10:00 Jan 23 01:00–07:00 Jan 26 01:00–10:00 Jan 27 01:00–06:00 Jan 28 02:00–10:00 Jan 31 01:00–10:00
February
Feb 1 01:00–10:00 Feb 2 01:00–10:00 Feb 3 01:00–10:00 Feb 7 01:00–10:00 Feb 8 01:00–10:00 Feb 9 01:00–10:00 Feb 11 01:00–10:00 Feb 12 01:00–10:00 Feb 14 01:00–10:00 Feb 15 01:00–10:00 Feb 16 01:00–12:00 Feb 17 15:00–24:00 Feb 18 01:00–10:00, 15:00–24:00 Feb 19 01:00–10:00, 15:00–24:00 Feb 21 01:00–10:00, 15:00–24:00 Feb 22 01:00–10:00, 15:00–24:00 Feb 23 01:00–09:00, 15:00–24:00 Feb 25 01:00–10:00, 15:00–24:00 Feb 26 15:00–24:00 Feb 27 01:00–10:00 Feb 28 01:00–10:00, 15:00–24:00
March
Mar 1 01:00–09:00, 15:00–24:00 Mar 2 01:00–10:00, 16:00–24:00 Mar 3 00:00–01:00, 15:00–24:00 Mar 4 00:00–10:00, 15:00–24:00 Mar 5 01:00–10:00, 15:00–24:00 Mar 7 01:00–10:00, 15:00–24:00 Mar 8 01:00–09:00 Mar 9 01:00–10:00, 15:00–24:00 Mar 11 01:00–10:00, 15:00–24:00 Mar 12 01:00–10:00 Mar 13 15:00–24:00 Mar 14 01:00–10:00, 15:00–24:00 Mar 15 01:00–10:00, 15:00–24:00 Mar 16 01:00–10:00, 15:00–24:00 Mar 17 15:00–24:00 Mar 18 01:00–11:00 Mar 19 01:00–10:00, 15:00–24:00 Mar 21 01:00–11:00, 15:00–24:00 Mar 22 00:00–10:00, 15:00–24:00 Mar 23 15:00–24:00 Mar 24 15:00–24:00 Mar 27 15:00–24:00 Mar 28 15:00–24:00 Mar 29 15:00–24:00 Mar 30 15:00–24:00 Mar 31 01:00–10:00, 15:00–24:00
April
Apr 1 01:00–10:00 Apr 2 01:00–09:00 Apr 3 15:00–24:00 Apr 4 01:00–10:00, 15:00–24:00 Apr 5 01:00–03:00, 15:00–24:00 Apr 6 02:00–10:00, 15:00–24:00 Apr 7 15:00–24:00 Apr 8 00:00–10:00 Apr 9 01:00–10:00 Apr 10 15:00–24:00 Apr 11 01:00–10:00, 15:00–24:00 Apr 12 15:00–24:00 Apr 13 01:00–10:00, 15:00–24:00 Apr 14 15:00–24:00 Apr 15 01:00–11:00, 15:00–24:00 Apr 16 01:00–10:00 Apr 18 01:00–10:00 Apr 19 01:00–10:00, 15:00–23:00 Apr 20 03:00–10:00, 15:00–24:00 Apr 21 15:00–24:00 Apr 22 01:00–10:00 Apr 23 01:00–10:00 Apr 25 01:00–10:00 Apr 26 01:00–10:00 Apr 27 01:00–10:00 Apr 28 01:00–08:00 Apr 29 01:00–10:00 Apr 30 01:00–10:00
May
May 1 01:00–06:00, 15:00–22:00 May 5 01:00–10:00 May 6 01:00–06:00 May 7 01:00–10:00 May 8 01:00–10:00 May 10 16:00–24:00 May 14 01:00–10:00 May 15 02:00–11:00 May 16 01:00–10:00 May 17 02:00–11:00 May 18 01:00–10:00 May 21 01:00–10:00 May 22 02:00–08:00 May 23 01:00–10:00 May 24 01:00–12:00 May 25 01:00–08:00 May 28 01:00–10:00 May 29 01:00–10:00 May 31 01:00–10:00
June
Jun 1 01:00–10:00 Jun 2 02:00–11:00 Jun 4 01:00–10:00 Jun 5 01:00–10:00 Jun 6 01:00–08:00 Jun 8 01:00–10:00 Jun 9 01:00–10:00 Jun 11 01:00–10:00 Jun 12 01:00–10:00 Jun 14 01:00–10:00 Jun 15 01:00–10:00 Jun 16 01:00–10:00 Jun 19 01:00–09:00 Jun 20 01:00–11:00 Jun 21 01:00–10:00 Jun 22 01:00–10:00 Jun 23 01:00–08:00 Jun 25 01:00–10:00 Jun 26 01:00–10:00 Jun 28 01:00–10:00 Jun 29 01:00–03:00 Jun 30 01:00–10:00
July
Jul 2 01:00–10:00 Jul 3 01:00–08:00 Jul 7 02:00–10:00 Jul 8 01:00–10:00 Jul 9 01:00–10:00 Jul 11 01:00–10:00 Jul 12 01:00–10:00 Jul 13 01:00–10:00 Jul 14 01:00–10:00 Jul 15 01:00–08:00 Jul 18 01:00–10:00 Jul 19 01:00–10:00 Jul 20 01:00–10:00 Jul 29 01:00–10:00 Jul 30 01:00–10:00
August
Aug 1 01:00–10:00 Aug 2 01:00–10:00 Aug 3 01:00–10:00 Aug 5 06:00–10:00 Aug 6 01:00–10:00 Aug 8 01:00–10:00 Aug 9 01:00–10:00 Aug 10 01:00–10:00 Aug 14 01:00–18:00 Aug 15 11:00–18:00 Aug 16 01:00–10:00 Aug 17 01:00–10:00 Aug 18 01:00–10:00 Aug 19 01:00–18:00 Aug 20 11:00–18:00 Aug 21 01:00–17:00 Aug 22 01:00–05:00 Aug 23 01:00–17:00 Aug 24 01:00–17:00 Aug 26 01:00–17:00 Aug 27 11:00–18:00 Aug 28 01:00–17:00 Aug 29 01:00–06:00 Aug 30 01:00–18:00 Aug 31 11:00–18:00
September
Sep 1 01:00–10:00 Sep 2 01:00–18:00 Sep 3 01:00–10:00 Sep 5 01:00–05:00, 11:00–17:00 Sep 6 01:00–18:00 Sep 7 01:00–18:00 Sep 8 11:00–16:00 Sep 9 01:00–10:00 Sep 10 01:00–07:00 Sep 12 01:00–10:00 Sep 13 01:00–10:00 Sep 15 01:00–09:00 Sep 16 02:00–10:00 Sep 25 01:00–11:00 Sep 26 01:00–11:00 Sep 28 01:00–10:00 Sep 30 02:00–12:00
October
Oct 1 01:00–10:00 Oct 3 01:00–10:00 Oct 4 01:00–10:00 Oct 5 01:00–10:00 Oct 6 01:00–07:00 Oct 7 01:00–10:00 Oct 8 01:00–11:00 Oct 10 01:00–10:00 Oct 12 01:00–11:00 Oct 14 01:00–10:00 Oct 15 01:00–11:00 Oct 16 01:00–10:00 Oct 17 01:00–07:00 Oct 20 01:00–10:00 Oct 21 02:00–05:00 Oct 25 01:00–11:00 Oct 26 01:00–05:00 Oct 31 01:00–10:00
November
Nov 1 01:00–10:00 Nov 3 01:00–10:00 Nov 4 01:00–08:00 Nov 5 01:00–07:00 Nov 9 01:00–04:00 Nov 12 01:00–10:00 Nov 15 01:00–10:00 Nov 16 01:00–10:00 Nov 18 01:00–10:00 Nov 21 01:00–08:00 Nov 22 01:00–06:00 Nov 26 02:00–08:00, 11:00–19:00 Nov 27 11:00–20:00 Nov 28 02:00–20:00 Nov 29 01:00–20:00 Nov 30 01:00–20:00
December
Dec 1 11:00–20:00 Dec 2 11:00–20:00 Dec 3 01:00–08:00 Dec 5 11:00–20:00 Dec 6 11:00–20:00 Dec 7 01:00–04:00, 11:00–20:00 Dec 10 01:00–07:00, 11:00–21:00 Dec 11 11:00–20:00 Dec 12 11:00–20:00 Dec 13 01:00–20:00 Dec 14 01:00–20:00 Dec 15 01:00–20:00 Dec 17 01:00–20:00 Dec 18 01:00–06:00, 11:00–20:00 Dec 19 11:00–20:00 Dec 21 01:00–20:00 Dec 22 11:00–21:00 Dec 23 07:00–12:00 Dec 24 01:00–22:00 Dec 26 01:00–07:00, 11:00–20:00 Dec 27 11:00–20:00 Dec 28 01:00–21:00 Dec 29 11:00–20:00 Dec 30 11:00–20:00 Dec 31 01:00–10:00