Most often in August, 28 days.
Highest follower count seen that year: 19,892.
July
Jul 25 00:00–01:00 Jul 27 19:00–24:00 Jul 28 00:00–03:00, 19:00–24:00 Jul 29 00:00–02:00, 19:00–24:00 Jul 30 01:00–02:00, 19:00–24:00 Jul 31 00:00–01:00, 19:00–24:00
August
Aug 1 00:00–02:00, 19:00–24:00 Aug 2 00:00–02:00 Aug 3 19:00–24:00 Aug 4 00:00–02:00, 19:00–24:00 Aug 5 19:00–24:00 Aug 6 01:00–02:00, 19:00–24:00 Aug 7 00:00–02:00, 19:00–24:00 Aug 8 00:00–02:00, 19:00–24:00 Aug 9 00:00–03:00 Aug 10 19:00–24:00 Aug 11 21:00–24:00 Aug 12 00:00–03:00, 19:00–24:00 Aug 13 00:00–02:00, 19:00–24:00 Aug 14 00:00–03:00, 21:00–24:00 Aug 15 00:00–03:00 Aug 17 19:00–24:00 Aug 18 00:00–02:00, 19:00–24:00 Aug 19 00:00–03:00, 19:00–24:00 Aug 20 00:00–03:00, 19:00–24:00 Aug 21 00:00–04:00, 19:00–24:00 Aug 22 01:00–03:00 Aug 24 19:00–24:00 Aug 25 00:00–03:00, 19:00–24:00 Aug 26 00:00–01:00, 19:00–23:00 Aug 27 00:00–03:00, 19:00–24:00 Aug 28 00:00–03:00, 19:00–24:00 Aug 29 00:00–03:00 Aug 31 19:00–24:00
September
Sep 1 00:00–02:00, 19:00–24:00 Sep 2 01:00–03:00, 19:00–24:00 Sep 3 00:00–03:00, 20:00–24:00 Sep 4 01:00–02:00, 19:00–24:00 Sep 5 00:00–01:00, 19:00–24:00 Sep 6 00:00–03:00, 21:00–24:00 Sep 7 00:00–04:00 Sep 10 19:00–23:00 Sep 11 00:00–04:00, 19:00–23:00 Sep 12 00:00–03:00 Sep 14 20:00–24:00 Sep 15 01:00–02:00, 19:00–24:00 Sep 16 00:00–03:00, 19:00–24:00 Sep 17 00:00–03:00, 19:00–24:00 Sep 18 00:00–02:00, 19:00–24:00 Sep 19 00:00–02:00, 21:00–24:00 Sep 21 19:00–24:00 Sep 22 00:00–03:00, 19:00–24:00 Sep 23 00:00–03:00, 19:00–21:00, 23:00–24:00 Sep 24 01:00–02:00, 19:00–24:00 Sep 25 00:00–03:00, 19:00–24:00 Sep 26 00:00–03:00 Sep 28 19:00–23:00 Sep 29 00:00–03:00, 19:00–24:00 Sep 30 00:00–03:00, 20:00–23:00
October
Oct 1 00:00–03:00, 19:00–24:00 Oct 2 00:00–03:00, 19:00–24:00 Oct 3 00:00–03:00, 20:00–23:00 Oct 4 00:00–04:00 Oct 6 21:00–24:00 Oct 7 00:00–03:00, 20:00–24:00 Oct 8 00:00–03:00, 19:00–24:00 Oct 9 00:00–03:00, 19:00–24:00 Oct 10 00:00–03:00, 19:00–24:00 Oct 11 00:00–02:00 Oct 13 19:00–24:00 Oct 14 00:00–04:00, 19:00–24:00 Oct 15 00:00–03:00, 19:00–24:00 Oct 16 02:00–03:00, 19:00–24:00 Oct 17 00:00–03:00, 19:00–24:00 Oct 18 00:00–02:00 Oct 20 20:00–24:00 Oct 21 01:00–03:00, 19:00–23:00 Oct 22 00:00–02:00, 19:00–22:00 Oct 23 00:00–03:00, 19:00–24:00 Oct 24 01:00–02:00, 20:00–24:00 Oct 25 00:00–03:00 Oct 27 21:00–24:00 Oct 28 00:00–03:00, 20:00–22:00 Oct 29 00:00–04:00, 20:00–24:00 Oct 30 00:00–04:00, 20:00–24:00 Oct 31 00:00–04:00, 20:00–24:00
November
Nov 1 00:00–03:00 Nov 3 20:00–24:00 Nov 4 00:00–04:00, 20:00–24:00 Nov 5 00:00–03:00, 20:00–24:00 Nov 6 00:00–04:00, 20:00–24:00 Nov 7 00:00–04:00, 20:00–24:00 Nov 8 00:00–04:00 Nov 10 20:00–24:00 Nov 11 00:00–04:00, 20:00–23:00 Nov 12 00:00–03:00, 20:00–23:00 Nov 13 00:00–04:00, 20:00–24:00 Nov 14 00:00–04:00 Nov 16 21:00–23:00 Nov 17 00:00–04:00, 21:00–24:00 Nov 18 00:00–05:00, 20:00–24:00 Nov 19 00:00–04:00, 20:00–21:00, 23:00–24:00 Nov 20 00:00–04:00, 21:00–24:00 Nov 21 00:00–04:00 Nov 23 20:00–24:00 Nov 24 00:00–01:00, 03:00–04:00, 20:00–24:00 Nov 25 00:00–01:00, 03:00–04:00, 21:00–24:00 Nov 26 00:00–04:00, 21:00–24:00 Nov 27 00:00–04:00, 20:00–24:00 Nov 28 02:00–05:00 Nov 30 20:00–24:00
December
Dec 1 00:00–04:00, 20:00–23:00 Dec 2 00:00–04:00, 22:00–24:00 Dec 3 00:00–04:00, 21:00–24:00 Dec 4 00:00–03:00, 20:00–23:00 Dec 5 00:00–04:00 Dec 7 20:00–24:00 Dec 8 01:00–02:00, 20:00–23:00 Dec 9 00:00–04:00, 20:00–24:00 Dec 10 00:00–01:00, 21:00–24:00 Dec 11 00:00–04:00, 19:00–24:00 Dec 12 00:00–03:00 Dec 14 20:00–24:00 Dec 15 00:00–04:00, 21:00–24:00 Dec 16 00:00–04:00, 20:00–24:00 Dec 17 00:00–03:00, 20:00–24:00 Dec 18 00:00–03:00, 20:00–24:00 Dec 21 20:00–23:00 Dec 22 00:00–01:00, 21:00–24:00 Dec 23 00:00–01:00, 20:00–24:00 Dec 24 00:00–04:00 Dec 26 20:00–24:00 Dec 27 00:00–04:00, 20:00–24:00 Dec 28 00:00–02:00, 20:00–24:00 Dec 29 00:00–04:00, 21:00–24:00 Dec 30 00:00–01:00, 03:00–04:00, 20:00–24:00 Dec 31 00:00–04:00