Stanford Mean Solar Magnetic Field (microTesla) 1977 Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec. day 01 . 5 2 -7 -13 13 2 -16 -9 9 6 -14 02 . 0 0 -17 -6 15 -12 -23 -13 6 1 -10 03 4 -6 -2 -16 -5 15 -18 -25 . 3 -14 -7 04 15 -8 -9 -12 1 13 -26 -23 3 13 -16 8 05 . -11 -17 -9 7 0 -31 -16 12 13 -11 26 06 3 -17 -22 -4 11 -19 -33 -5 18 11 -1 46 07 -7 -12 -20 0 7 -32 -26 -1 22 -6 11 55 08 -14 . -13 5 -5 -31 -14 11 17 -13 31 53 09 -9 . -9 8 . . -7 25 8 -13 46 46 10 -11 . -3 2 -22 0 3 20 4 -4 48 26 11 -8 21 3 -4 . 7 20 17 6 2 51 . 12 . 19 11 -7 -29 17 29 12 13 12 32 -2 13 . 13 18 -14 -20 28 30 11 19 28 14 10 14 8 11 3 -8 -5 38 24 5 23 35 -4 . 15 6 9 . -8 4 40 26 7 40 46 -10 1 16 9 -3 -9 -11 12 31 18 . . 39 -18 -6 17 6 -12 -12 -9 20 24 13 5 38 20 -24 . 18 3 -13 -13 1 29 18 4 13 41 6 -5 6 19 0 -20 -15 13 27 19 1 19 31 6 -11 8 20 -4 . -12 18 19 16 -1 23 17 1 -12 . 21 . . -7 21 12 10 6 24 2 3 . . 22 -14 3 2 13 . 2 9 22 -3 7 -7 . 23 -12 7 . 17 1 -2 22 18 -2 3 -4 -5 24 -12 12 15 9 -1 -7 25 8 -6 -3 0 -1 25 -7 13 13 6 4 -15 31 4 -1 -9 2 . 26 -6 11 13 9 -10 -10 30 0 -3 -5 4 . 27 0 9 10 7 -10 4 24 2 -8 -5 7 . 28 6 5 8 2 -10 15 6 -2 . -6 5 . 29 8 4 -10 -4 19 4 -6 -8 5 -2 -9 30 7 7 -11 3 14 -4 -6 3 6 -11 . 31 7 6 6 -10 -11 8 -20