Most often in October, 27 days.
Highest follower count seen that year: 25,062.
April
Apr 7 03:00–12:00 Apr 8 03:00–12:00 Apr 9 03:00–12:00 Apr 10 03:00–12:00 Apr 11 03:00–12:00 Apr 14 03:00–12:00 Apr 15 03:00–12:00 Apr 16 03:00–12:00 Apr 17 03:00–12:00 Apr 18 03:00–12:00 Apr 22 18:00–24:00 Apr 23 01:00–03:00, 18:00–24:00 Apr 24 00:00–03:00 Apr 25 03:00–12:00 Apr 29 03:00–12:00 Apr 30 06:00–07:00, 09:00–12:00
May
May 1 03:00–12:00 May 2 03:00–06:00, 09:00–12:00 May 5 04:00–12:00 May 6 03:00–12:00 May 7 03:00–12:00 May 8 03:00–07:00, 09:00–12:00 May 9 03:00–12:00 May 12 09:00–12:00 May 13 04:00–12:00 May 14 03:00–12:00 May 15 03:00–06:00, 09:00–12:00 May 16 03:00–12:00 May 19 03:00–12:00 May 20 03:00–12:00 May 21 03:00–08:00, 10:00–12:00 May 22 03:00–12:00 May 23 03:00–12:00 May 24 03:00–12:00 May 26 03:00–05:00, 07:00–12:00 May 27 03:00–12:00 May 28 03:00–12:00 May 29 03:00–12:00 May 30 03:00–12:00 May 31 03:00–09:00
June
Jun 2 03:00–12:00 Jun 3 03:00–12:00 Jun 4 03:00–12:00 Jun 5 03:00–12:00 Jun 6 03:00–12:00 Jun 7 03:00–10:00 Jun 9 03:00–12:00 Jun 10 03:00–12:00 Jun 11 03:00–12:00 Jun 12 03:00–12:00 Jun 13 03:00–12:00 Jun 14 03:00–08:00, 11:00–12:00 Jun 16 05:00–12:00 Jun 17 03:00–12:00 Jun 18 03:00–08:00, 10:00–12:00 Jun 19 03:00–08:00, 10:00–11:00 Jun 20 03:00–08:00 Jun 22 03:00–13:00 Jun 23 03:00–12:00 Jun 24 03:00–12:00 Jun 25 03:00–12:00 Jun 26 03:00–12:00 Jun 27 04:00–12:00 Jun 29 03:00–12:00 Jun 30 03:00–12:00
July
Jul 1 03:00–12:00 Jul 2 03:00–12:00 Jul 3 03:00–12:00 Jul 4 03:00–12:00 Jul 6 03:00–07:00, 10:00–12:00 Jul 7 03:00–12:00 Jul 8 03:00–12:00 Jul 9 03:00–12:00 Jul 10 03:00–12:00 Jul 11 03:00–08:00 Jul 14 03:00–12:00 Jul 15 03:00–12:00 Jul 16 03:00–12:00 Jul 17 03:00–12:00 Jul 18 03:00–12:00 Jul 28 03:00–12:00 Jul 29 03:00–12:00 Jul 30 03:00–12:00 Jul 31 03:00–12:00
August
Aug 1 03:00–12:00 Aug 3 03:00–08:00, 10:00–12:00 Aug 4 03:00–12:00 Aug 5 06:00–12:00 Aug 6 03:00–12:00 Aug 7 03:00–12:00 Aug 8 03:00–12:00 Aug 9 03:00–11:00 Aug 11 03:00–11:00 Aug 12 03:00–11:00 Aug 13 03:00–11:00 Aug 14 03:00–11:00 Aug 15 03:00–11:00 Aug 17 03:00–09:00 Aug 18 03:00–12:00 Aug 19 03:00–12:00 Aug 20 03:00–11:00 Aug 21 03:00–11:00 Aug 22 03:00–11:00 Aug 25 03:00–09:00 Aug 26 03:00–11:00 Aug 27 03:00–11:00 Aug 28 03:00–11:00 Aug 29 03:00–11:00
September
Sep 1 03:00–05:00 Sep 5 03:00–11:00 Sep 8 03:00–11:00 Sep 9 03:00–11:00 Sep 10 03:00–11:00 Sep 11 03:00–11:00 Sep 12 03:00–11:00 Sep 13 03:00–09:00 Sep 15 03:00–11:00 Sep 16 03:00–11:00 Sep 17 03:00–11:00 Sep 18 03:00–11:00 Sep 19 03:00–11:00 Sep 22 03:00–11:00 Sep 23 03:00–12:00 Sep 24 03:00–11:00 Sep 25 03:00–11:00 Sep 26 03:00–11:00 Sep 27 03:00–09:00 Sep 29 03:00–11:00 Sep 30 03:00–11:00
October
Oct 1 03:00–11:00 Oct 2 03:00–09:00 Oct 3 03:00–11:00 Oct 4 03:00–09:00 Oct 6 03:00–11:00 Oct 7 03:00–11:00 Oct 8 03:00–11:00 Oct 9 03:00–11:00 Oct 10 03:00–11:00 Oct 12 03:00–09:00 Oct 13 03:00–11:00 Oct 14 03:00–11:00 Oct 15 03:00–11:00 Oct 16 03:00–11:00 Oct 17 03:00–11:00 Oct 20 03:00–09:00 Oct 21 03:00–11:00 Oct 22 03:00–11:00 Oct 23 03:00–11:00 Oct 24 03:00–11:00 Oct 25 03:00–09:00 Oct 26 04:00–10:00 Oct 27 04:00–12:00 Oct 28 04:00–12:00 Oct 29 04:00–10:00 Oct 30 04:00–12:00 Oct 31 04:00–12:00
November
Nov 1 04:00–11:00 Nov 3 04:00–12:00 Nov 4 04:00–12:00 Nov 5 04:00–12:00 Nov 6 04:00–10:00 Nov 10 04:00–12:00 Nov 11 04:00–12:00 Nov 12 04:00–12:00 Nov 13 04:00–12:00 Nov 14 04:00–12:00 Nov 15 04:00–09:00 Nov 17 04:00–12:00 Nov 18 04:00–12:00 Nov 19 04:00–12:00 Nov 20 04:00–10:00 Nov 21 04:00–12:00 Nov 22 04:00–10:00 Nov 24 04:00–12:00 Nov 25 04:00–12:00 Nov 26 04:00–05:00 Nov 30 04:00–07:00
December
Dec 1 04:00–12:00 Dec 2 04:00–12:00 Dec 3 04:00–12:00 Dec 4 04:00–12:00 Dec 5 04:00–12:00 Dec 6 04:00–10:00 Dec 8 04:00–12:00 Dec 9 04:00–12:00 Dec 10 04:00–12:00 Dec 11 04:00–12:00 Dec 12 04:00–12:00 Dec 15 04:00–12:00 Dec 16 04:00–12:00 Dec 18 04:00–12:00 Dec 19 04:00–12:00 Dec 20 04:00–10:00 Dec 22 04:00–12:00 Dec 23 04:00–12:00 Dec 24 04:00–10:00 Dec 29 05:00–12:00 Dec 30 04:00–10:00