TABLE 4 ESTIMATES OF 13-MONTH SMOOTH SOLAR ACTIVITY FOR BALANCE OF CYCLE 25 WITH A MEAN CYCLE GIVEN FOR CYCLE 26 TIME SUNSPOT NUMBERS GEOMAGNETIC INDEX (Ap) PERCENTILE PERCENTILE 95.0% 50% 5.0% 95.0% 50% 5.0% 2026.2503 APR 99.4 92.8 89.2 13.9 13.1 12.1 2026.3337 MAY 102.9 91.3 85.2 15.1 13.4 12.0 2026.4170 JUN 104.5 89.4 79.8 16.4 13.7 11.3 2026.5003 JUL 102.7 87.3 74.4 17.6 14.0 10.1 2026.5837 AUG 103.7 85.2 71.2 18.9 14.2 9.9 2026.6670 SEP 104.8 82.9 69.1 20.2 14.4 10.2 2026.7503 OCT 105.2 80.3 66.4 20.8 14.5 10.7 2026.8337 NOV 104.9 77.9 62.6 21.0 14.8 11.2 2026.9170 DEC 101.5 75.3 58.7 20.8 15.1 11.5 2027.0003 JAN 98.2 72.9 54.5 21.4 15.5 11.6 2027.0837 FEB 98.3 71.1 50.9 21.4 15.6 11.3 2027.1670 MAR 100.5 68.9 45.6 21.6 15.6 11.0 2027.2503 APR 102.2 66.5 41.4 22.0 15.4 11.0 2027.3337 MAY 103.6 64.4 37.9 22.0 15.0 10.8 2027.4170 JUN 104.8 62.5 34.5 22.6 14.8 10.0 2027.5003 JUL 104.0 60.4 32.2 23.3 14.6 9.4 2027.5837 AUG 102.7 58.1 29.9 23.9 14.3 9.4 2027.6670 SEP 100.2 55.9 27.5 24.3 14.2 9.4 2027.7503 OCT 96.5 53.8 26.0 24.6 14.2 9.3 2027.8337 NOV 92.4 51.8 24.8 24.3 13.9 9.1 2027.9170 DEC 89.0 49.4 24.0 23.5 13.6 8.9 2028.0003 JAN 88.3 47.4 22.4 22.5 13.4 8.5 2028.0837 FEB 88.7 46.1 20.0 21.7 13.3 8.1 2028.1670 MAR 86.4 44.5 18.7 21.5 13.5 7.8 2028.2503 APR 82.9 42.7 18.7 21.4 13.7 7.4 2028.3337 MAY 78.1 40.7 19.2 21.5 14.1 7.1 2028.4170 JUN 73.3 39.1 19.0 21.3 14.4 7.3 2028.5003 JUL 71.1 37.9 17.8 20.9 14.5 7.8 2028.5837 AUG 69.9 36.5 16.6 20.1 14.4 8.3 2028.6670 SEP 66.7 34.8 15.1 20.0 14.2 8.7 2028.7503 OCT 63.5 33.1 12.9 20.1 14.0 8.6 2028.8337 NOV 62.7 32.4 9.5 19.8 13.8 8.4 2028.9170 DEC 62.3 31.6 6.4 19.3 13.8 8.4 2029.0003 JAN 59.5 30.4 3.5 18.8 13.9 8.3 2029.0837 FEB 55.1 29.2 1.7 18.1 13.8 8.0 2029.1670 MAR 50.9 27.8 0.6 17.3 13.5 7.7 2029.2503 APR 48.9 26.4 0.0 17.3 13.1 7.2 2029.3337 MAY 47.7 24.9 0.0 17.3 12.8 7.0 2029.4170 JUN 46.3 23.6 0.0 17.3 12.5 6.9 2029.5003 JUL 44.7 22.4 0.0 17.4 12.4 6.6 2029.5837 AUG 42.5 21.1 0.0 17.5 12.5 6.4 2029.6670 SEP 39.6 19.7 0.0 17.7 12.4 6.7 2029.7503 OCT 36.3 18.5 0.0 17.7 12.3 6.5 2029.8337 NOV 32.3 17.5 0.0 17.4 12.1 6.5 2029.9170 DEC 29.7 16.1 0.7 17.2 11.9 6.3 2030.0003 JAN 27.7 14.6 1.3 16.2 11.5 6.2 2030.0837 FEB 25.0 13.3 1.0 14.7 11.0 6.2 2030.1670 MAR 23.2 12.2 0.3 13.9 10.7 6.2 2030.2503 APR 23.4 11.3 0.2 14.0 10.5 6.2 2030.3337 MAY 23.2 10.5 0.6 13.7 10.1 6.2 2030.4170 JUN 23.0 9.8 1.3 13.2 9.8 6.0 2030.5003 JUL 21.3 9.2 1.8 12.9 9.6 5.8 2030.5837 AUG 21.5 8.6 1.2 12.5 9.4 5.7 2030.6670 SEP 21.1 7.9 0.6 11.8 9.2 5.8 2030.7503 OCT 19.7 7.3 0.0 11.4 9.0 5.3 2030.8337 NOV 17.2 6.7 0.0 11.2 8.7 5.0 2030.9170 DEC 17.3 6.9 0.0 11.2 8.7 4.9 2031.0003 JAN 18.4 7.8 0.7 11.4 8.8 4.7 2031.0837 FEB 20.3 9.1 1.3 11.7 8.9 4.7 2031.1670 MAR 22.1 10.4 1.7 11.8 9.0 4.5 2031.2503 APR 24.9 11.6 2.3 12.0 9.1 4.2 2031.3337 MAY 27.8 13.0 2.5 12.1 9.1 4.0 2031.4170 JUN 32.5 14.8 3.2 12.2 9.2 3.9 2031.5003 JUL 36.2 16.7 4.4 12.3 9.3 3.7 2031.5837 AUG 40.0 18.8 5.0 12.6 9.4 3.6 2031.6670 SEP 45.6 21.0 5.6 12.9 9.7 3.6 2031.7503 OCT 52.6 23.5 6.1 13.3 10.0 3.8 2031.8337 NOV 63.1 26.6 6.1 13.8 10.4 4.2 2031.9170 DEC 71.9 29.9 6.3 14.6 10.6 4.5 2032.0003 JAN 78.8 33.1 7.3 15.7 10.9 4.7 2032.0837 FEB 88.8 36.7 7.3 16.1 11.1 4.8 2032.1670 MAR 99.7 40.7 7.3 16.3 11.3 5.0 2032.2503 APR 109.4 44.7 8.0 16.9 11.4 5.1 2032.3337 MAY 121.3 49.1 8.2 18.0 11.6 5.3 2032.4170 JUN 135.7 53.9 8.9 18.9 11.9 5.4 2032.5003 JUL 145.7 58.8 10.0 19.1 12.1 5.6 2032.5837 AUG 152.6 64.1 11.7 19.2 12.3 5.8 2032.6670 SEP 159.7 69.6 13.3 19.0 12.6 6.0 2032.7503 OCT 167.7 74.9 15.6 18.6 12.7 6.1 2032.8337 NOV 176.8 80.0 16.9 18.5 12.7 6.1 2032.9170 DEC 186.4 85.3 17.0 18.9 12.8 6.1 2033.0003 JAN 195.5 91.2 19.1 18.8 12.9 6.3 2033.0837 FEB 203.4 97.0 20.9 17.8 13.0 6.5 2033.1670 MAR 211.7 102.6 22.7 17.9 13.2 6.7 2033.2503 APR 216.9 108.0 24.6 18.4 13.4 7.1 2033.3337 MAY 223.4 113.7 25.4 19.1 13.7 7.0 2033.4170 JUN 224.9 118.9 26.5 19.6 14.2 7.0 2033.5003 JUL 225.7 123.4 27.6 20.3 14.5 7.1 2033.5837 AUG 231.1 127.1 28.4 20.3 14.5 7.2 2033.6670 SEP 233.8 130.6 29.3 20.3 14.6 7.7 2033.7503 OCT 236.3 134.3 29.4 20.5 14.7 8.1 2033.8337 NOV 239.2 137.7 28.9 20.8 14.8 8.0 2033.9170 DEC 241.6 141.1 28.5 21.2 14.8 8.0 2034.0003 JAN 248.2 144.4 29.4 21.3 14.6 8.4 2034.0837 FEB 255.6 147.5 30.6 21.4 14.6 8.6 2034.1670 MAR 260.5 150.2 32.8 21.6 14.6 8.4 2034.2503 APR 264.8 153.0 36.1 22.0 14.5 8.4 2034.3337 MAY 269.5 155.4 38.1 22.7 14.4 8.6 2034.4170 JUN 272.7 157.2 40.4 22.4 14.1 8.6 2034.5003 JUL 274.4 158.0 44.2 21.3 13.8 8.5 2034.5837 AUG 275.1 158.0 48.5 20.6 13.7 8.3 2034.6670 SEP 276.4 158.8 52.8 20.1 13.6 8.0 2034.7503 OCT 276.2 160.2 54.7 19.7 13.5 7.6 2034.8337 NOV 275.2 161.0 56.7 19.6 13.5 7.5 2034.9170 DEC 276.2 161.2 60.3 19.3 13.5 7.8 2035.0003 JAN 275.3 160.2 62.7 19.1 13.7 7.7 2035.0837 FEB 269.5 158.5 66.2 18.9 13.9 7.6 2035.1670 MAR 263.0 157.1 68.8 18.9 14.0 7.5 2035.2503 APR 257.3 156.7 71.6 19.5 13.9 7.2 2035.3337 MAY 253.6 156.9 73.6 20.4 14.0 7.1 2035.4170 JUN 251.7 156.6 73.3 22.0 14.4 7.1 2035.5003 JUL 249.8 156.0 72.5 23.4 14.7 7.1 2035.5837 AUG 248.7 155.6 73.6 24.0 14.9 7.3 2035.6670 SEP 246.7 155.0 76.8 25.1 15.1 7.3 2035.7503 OCT 244.9 154.3 76.9 25.7 15.3 7.0 2035.8337 NOV 242.7 153.3 75.2 24.9 15.3 7.1 2035.9170 DEC 241.9 152.0 74.2 24.8 15.3 6.7 2036.0003 JAN 239.5 150.6 75.1 24.0 15.3 6.3 2036.0837 FEB 234.9 148.4 75.8 22.2 15.3 6.1 2036.1670 MAR 230.5 145.4 73.9 22.5 15.5 6.3 2036.2503 APR 226.5 142.7 73.2 23.2 15.7 6.5 2036.3337 MAY 222.0 140.7 74.9 23.2 15.7 6.7 2036.4170 JUN 216.0 138.6 76.5 22.7 15.7 7.1 2036.5003 JUL 210.7 135.7 74.5 22.0 15.6 7.6 2036.5837 AUG 205.8 132.7 71.2 21.9 15.7 7.7 2036.6670 SEP 202.0 130.3 69.5 22.7 15.9 8.1 2036.7503 OCT 200.2 128.2 68.9 23.6 16.2 8.7 2036.8337 NOV 194.9 125.5 65.8 23.8 16.4 8.9 2036.9170 DEC 191.9 122.7 58.8 23.8 16.6 9.3 2037.0003 JAN 189.9 119.8 57.2 23.8 16.6 9.7 2037.0837 FEB 185.1 117.3 59.1 23.4 16.6 10.1 2037.1670 MAR 179.7 115.3 57.6 22.5 16.5 10.5 2037.2503 APR 174.1 113.5 54.5 22.7 16.4 10.7 2037.3337 MAY 168.6 111.5 52.9 22.9 16.5 11.5 2037.4170 JUN 163.9 109.2 51.6 23.0 16.6 11.7 2037.5003 JUL 160.3 106.3 49.1 22.4 16.7 11.9 2037.5837 AUG 154.9 103.4 46.5 21.5 16.5 11.9 2037.6670 SEP 146.1 100.2 45.0 21.2 16.3 11.7 2037.7503 OCT 138.4 96.7 44.3 21.7 16.1 11.4 2037.8337 NOV 136.9 93.7 44.5 21.7 16.1 11.5 2037.9170 DEC 135.5 90.9 43.0 22.1 16.1 11.4 2038.0003 JAN 131.3 88.4 40.6 22.5 16.2 11.2 2038.0837 FEB 126.7 86.0 40.9 22.3 16.2 11.0 2038.1670 MAR 121.9 83.3 39.8 22.3 16.0 10.8 2038.2503 APR 116.7 80.6 37.9 22.7 15.8 10.7 2038.3337 MAY 115.8 78.0 36.5 22.9 15.5 10.6 2038.4170 JUN 116.7 75.4 34.0 23.4 15.3 10.3 2038.5003 JUL 115.2 72.7 31.6 24.0 15.0 10.1 2038.5837 AUG 113.7 70.1 27.9 24.7 14.9 10.1 2038.6670 SEP 111.2 67.9 24.9 25.3 14.8 10.1 2038.7503 OCT 107.6 65.9 22.9 25.4 14.8 10.5 2038.8337 NOV 103.7 64.0 20.0 25.3 14.7 10.4 2038.9170 DEC 100.4 61.7 17.6 24.8 14.5 10.2 2039.0003 JAN 99.3 59.5 16.1 23.9 14.3 10.0 2039.0837 FEB 98.2 57.6 14.9 23.0 14.1 9.4 2039.1670 MAR 95.1 55.6 13.6 22.5 14.2 8.8 2039.2503 APR 91.4 53.5 13.5 22.1 14.2 8.1 2039.3337 MAY 86.4 51.3 13.6 21.8 14.3 7.5 2039.4170 JUN 84.7 49.5 13.1 21.4 14.5 7.4 2039.5003 JUL 85.0 48.0 12.9 20.8 14.4 7.7 2039.5837 AUG 82.2 46.4 12.6 20.0 14.3 8.1 2039.6670 SEP 77.6 44.3 12.0 20.0 14.1 8.5 2039.7503 OCT 73.8 42.1 11.1 20.2 13.9 8.5 2039.8337 NOV 70.0 40.7 11.0 19.8 13.7 8.5 2039.9170 DEC 68.3 39.4 10.3 19.4 13.6 8.4 2040.0003 JAN 65.8 37.7 9.2 18.9 13.6 8.4 2040.0837 FEB 64.4 36.0 8.8 18.2 13.6 8.1 2040.1670 MAR 62.8 34.3 7.4 17.3 13.5 7.7 2040.2503 APR 61.9 32.8 6.0 17.3 13.3 7.1 2040.3337 MAY 60.4 31.1 5.9 17.4 13.2 6.8 2040.4170 JUN 58.5 29.7 5.8 17.5 13.1 6.6 2040.5003 JUL 56.4 28.3 5.6 17.5 12.9 6.5 2040.5837 AUG 54.1 26.9 5.4 17.7 12.9 6.6 2040.6670 SEP 51.2 25.4 4.3 18.0 12.7 6.5 2040.7503 OCT 48.1 24.0 3.3 17.9 12.6 6.4 2040.8337 NOV 43.8 22.8 2.9 17.6 12.3 6.4 2040.9170 DEC 38.5 21.2 2.7 17.3 12.0 6.2 2041.0003 JAN 34.9 19.3 2.1 16.3 11.7 6.1 2041.0837 FEB 33.1 17.6 1.5 14.9 11.2 6.0 2041.1670 MAR 32.1 16.2 1.2 13.8 10.9 6.1 2041.2503 APR 31.6 15.0 1.1 13.9 10.5 6.2 2041.3337 MAY 31.0 14.0 1.0 13.6 10.2 6.2 2041.4170 JUN 30.2 13.1 0.8 13.2 9.8 6.0 2041.5003 JUL 27.9 12.2 0.6 12.9 9.5 5.9 2041.5837 AUG 25.2 11.4 0.3 12.6 9.3 5.8 2041.6670 SEP 23.3 10.6 0.1 11.9 9.1 5.7 2041.7503 OCT 21.6 9.8 0.0 11.4 8.9 5.2