Most often in October, 27 days.
Highest follower count seen that year: 31,526.
January
Jan 6 22:00–24:00 Jan 7 00:00–07:00, 18:00–24:00 Jan 8 00:00–03:00, 19:00–23:00 Jan 9 00:00–04:00 Jan 10 20:00–24:00 Jan 11 00:00–05:00, 21:00–24:00 Jan 12 00:00–06:00 Jan 13 21:00–24:00 Jan 14 00:00–06:00, 21:00–24:00 Jan 15 00:00–05:00, 23:00–24:00 Jan 16 00:00–07:00 Jan 17 23:00–24:00 Jan 18 00:00–06:00, 23:00–24:00 Jan 19 00:00–06:00 Jan 20 23:00–24:00 Jan 21 00:00–07:00, 21:00–24:00 Jan 22 00:00–05:00, 23:00–24:00 Jan 23 00:00–07:00 Jan 24 23:00–24:00 Jan 25 00:00–07:00, 23:00–24:00 Jan 26 00:00–06:00 Jan 27 23:00–24:00 Jan 28 00:00–08:00
February
Feb 4 21:00–24:00 Feb 5 00:00–04:00 Feb 6 17:00–18:00 Feb 16 22:00–24:00 Feb 17 00:00–03:00, 22:00–24:00 Feb 18 00:00–03:00, 23:00–24:00 Feb 19 00:00–04:00 Feb 21 00:00–04:00, 23:00–24:00 Feb 22 00:00–05:00 Feb 23 00:00–05:00 Feb 24 22:00–24:00 Feb 25 00:00–03:00, 23:00–24:00 Feb 26 00:00–05:00 Feb 27 00:00–06:00 Feb 28 01:00–06:00
March
Mar 3 00:00–06:00 Mar 4 01:00–05:00 Mar 5 00:00–05:00 Mar 6 00:00–08:00 Mar 9 00:00–07:00, 21:00–24:00 Mar 10 00:00–04:00 Mar 11 00:00–06:00 Mar 12 00:00–06:00, 23:00–24:00 Mar 13 02:00–07:00 Mar 16 04:00–08:00 Mar 17 23:00–24:00 Mar 18 00:00–06:00, 23:00–24:00 Mar 19 00:00–06:00, 23:00–24:00 Mar 20 00:00–07:00 Mar 21 23:00–24:00 Mar 22 00:00–07:00, 23:00–24:00 Mar 23 00:00–07:00 Mar 24 23:00–24:00 Mar 25 00:00–02:00, 23:00–24:00 Mar 26 00:00–05:00 Mar 28 23:00–24:00 Mar 29 00:00–03:00, 23:00–24:00 Mar 30 00:00–05:00 Mar 31 23:00–24:00
April
Apr 1 00:00–08:00 Apr 2 23:00–24:00 Apr 3 00:00–06:00 Apr 5 00:00–06:00, 23:00–24:00 Apr 6 00:00–06:00, 23:00–24:00 Apr 7 00:00–06:00, 23:00–24:00 Apr 8 00:00–07:00 Apr 9 23:00–24:00 Apr 10 00:00–07:00 Apr 14 23:00–24:00 Apr 15 00:00–08:00 Apr 20 04:00–05:00 Apr 21 00:00–06:00 Apr 23 00:00–08:00 Apr 25 00:00–06:00 Apr 27 00:00–09:00 Apr 28 02:00–07:00
May
May 1 02:00–09:00 May 3 01:00–07:00 May 4 03:00–08:00 May 7 01:00–06:00 May 9 02:00–10:00 May 10 03:00–09:00 May 12 02:00–05:00 May 14 04:00–08:00 May 16 04:00–10:00 May 17 02:00–08:00 May 18 02:00–08:00 May 22 02:00–10:00 May 23 02:00–07:00 May 25 02:00–09:00 May 26 05:00–09:00 May 28 04:00–10:00 May 30 04:00–09:00 May 31 02:00–10:00
June
Jun 1 03:00–08:00 Jun 6 02:00–08:00 Jun 7 04:00–07:00 Jun 8 00:00–04:00, 06:00–10:00 Jun 9 23:00–24:00 Jun 10 00:00–04:00 Jun 13 03:00–08:00 Jun 14 02:00–09:00 Jun 15 04:00–10:00 Jun 16 07:00–12:00 Jun 17 02:00–09:00 Jun 20 00:00–07:00 Jun 21 04:00–09:00 Jun 22 03:00–08:00 Jun 25 02:00–07:00 Jun 26 00:00–07:00 Jun 27 23:00–24:00 Jun 28 00:00–04:00, 09:00–12:00 Jun 29 04:00–11:00 Jun 30 00:00–06:00, 08:00–10:00
July
Jul 2 00:00–10:00 Jul 4 01:00–09:00 Jul 6 01:00–08:00 Jul 7 02:00–09:00 Jul 8 03:00–08:00 Jul 9 02:00–09:00 Jul 12 01:00–09:00 Jul 13 01:00–09:00 Jul 14 01:00–08:00 Jul 15 01:00–08:00 Jul 18 02:00–10:00 Jul 19 01:00–09:00 Jul 20 01:00–08:00 Jul 21 03:00–08:00 Jul 22 01:00–08:00 Jul 23 01:00–06:00 Jul 24 01:00–07:00 Jul 25 00:00–07:00 Jul 26 01:00–08:00
August
Aug 4 01:00–09:00 Aug 5 06:00–08:00 Aug 6 01:00–08:00 Aug 7 01:00–06:00 Aug 9 00:00–07:00 Aug 10 00:00–08:00 Aug 11 01:00–08:00 Aug 14 01:00–08:00 Aug 15 02:00–08:00 Aug 16 01:00–08:00 Aug 17 01:00–08:00 Aug 18 01:00–08:00 Aug 20 01:00–09:00 Aug 21 01:00–06:00 Aug 22 03:00–08:00 Aug 26 03:00–08:00 Aug 27 01:00–07:00 Aug 28 01:00–08:00 Aug 29 01:00–08:00 Aug 30 01:00–08:00 Aug 31 01:00–08:00
September
Sep 3 01:00–08:00 Sep 4 02:00–08:00, 22:00–24:00 Sep 5 00:00–04:00 Sep 6 01:00–06:00, 23:00–24:00 Sep 7 00:00–04:00 Sep 10 01:00–07:00 Sep 11 01:00–07:00 Sep 12 02:00–07:00 Sep 14 02:00–08:00 Sep 15 01:00–07:00 Sep 17 01:00–08:00 Sep 18 01:00–08:00 Sep 19 21:00–24:00 Sep 20 00:00–02:00 Sep 22 19:00–24:00 Sep 23 22:00–24:00 Sep 24 00:00–05:00, 22:00–24:00 Sep 25 00:00–01:00 Sep 26 01:00–02:00 Sep 27 22:00–24:00 Sep 28 00:00–03:00 Sep 30 22:00–24:00
October
Oct 1 00:00–04:00, 22:00–24:00 Oct 2 00:00–03:00, 23:00–24:00 Oct 3 00:00–03:00 Oct 4 22:00–24:00 Oct 5 00:00–06:00, 22:00–24:00 Oct 6 00:00–03:00 Oct 8 01:00–05:00 Oct 9 22:00–24:00 Oct 10 00:00–04:00, 23:00–24:00 Oct 11 00:00–02:00, 04:00–06:00, 22:00–24:00 Oct 12 00:00–06:00, 23:00–24:00 Oct 13 00:00–04:00 Oct 14 23:00–24:00 Oct 15 00:00–05:00, 23:00–24:00 Oct 16 00:00–06:00, 23:00–24:00 Oct 17 00:00–05:00, 23:00–24:00 Oct 18 00:00–05:00, 23:00–24:00 Oct 19 00:00–05:00 Oct 21 23:00–24:00 Oct 22 00:00–01:00, 23:00–24:00 Oct 23 00:00–05:00 Oct 24 00:00–04:00 Oct 26 00:00–05:00 Oct 27 00:00–04:00 Oct 28 23:00–24:00 Oct 29 00:00–03:00 Oct 30 01:00–06:00
November
Nov 1 00:00–07:00 Nov 2 02:00–06:00 Nov 3 01:00–04:00 Nov 7 00:00–05:00 Nov 8 03:00–07:00, 23:00–24:00 Nov 9 00:00–02:00, 23:00–24:00 Nov 10 00:00–04:00 Nov 11 23:00–24:00 Nov 12 00:00–05:00, 23:00–24:00 Nov 13 00:00–05:00 Nov 14 00:00–06:00 Nov 15 04:00–08:00 Nov 17 01:00–06:00 Nov 19 01:00–07:00, 23:00–24:00 Nov 20 00:00–05:00 Nov 21 00:00–03:00 Nov 22 00:00–07:00 Nov 23 01:00–05:00 Nov 26 00:00–06:00 Nov 27 01:00–06:00 Nov 29 00:00–06:00 Nov 30 02:00–08:00
December
Dec 1 01:00–06:00 Dec 3 00:00–03:00 Dec 4 00:00–06:00 Dec 5 03:00–08:00 Dec 7 03:00–08:00 Dec 8 02:00–07:00 Dec 11 01:00–03:00 Dec 12 01:00–02:00 Dec 13 00:00–04:00 Dec 14 01:00–06:00 Dec 15 01:00–06:00 Dec 16 23:00–24:00 Dec 17 00:00–03:00 Dec 19 22:00–24:00 Dec 20 00:00–04:00, 20:00–24:00 Dec 21 00:00–02:00 Dec 22 03:00–10:00 Dec 23 20:00–24:00 Dec 24 00:00–01:00, 21:00–24:00 Dec 25 00:00–04:00 Dec 26 21:00–24:00 Dec 27 00:00–03:00 Dec 28 00:00–07:00, 22:00–24:00 Dec 29 00:00–04:00, 22:00–24:00 Dec 30 00:00–04:00, 22:00–24:00 Dec 31 00:00–04:00