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% 2023.3337 MAY 135.1 124.9 117.1 11.3 10.5 9.9 2023.4170 JUN 145.0 126.8 112.4 11.4 10.3 9.2 2023.5003 JUL 157.4 128.2 108.7 11.9 10.4 9.2 2023.5837 AUG 166.1 128.9 104.2 12.5 10.6 9.4 2023.6670 SEP 172.8 130.3 99.5 13.1 10.7 9.2 2023.7503 OCT 178.7 132.0 96.3 13.5 10.6 8.9 2023.8337 NOV 183.5 133.4 94.6 13.5 10.7 8.6 2023.9170 DEC 193.4 134.4 94.0 13.6 10.8 8.8 2024.0003 JAN 196.4 134.0 94.0 14.0 10.8 8.3 2024.0837 FEB 192.8 133.5 91.0 14.6 11.0 8.3 2024.1670 MAR 189.2 133.5 88.3 14.5 11.0 8.0 2024.2503 APR 190.6 134.2 89.0 14.0 10.8 7.5 2024.3337 MAY 194.2 135.1 91.2 13.6 10.7 7.9 2024.4170 JUN 197.4 135.4 90.7 14.5 10.8 8.2 2024.5003 JUL 199.5 135.3 92.5 15.5 10.9 8.1 2024.5837 AUG 199.8 135.5 91.1 16.2 11.1 8.3 2024.6670 SEP 197.8 135.6 86.2 17.0 11.2 8.3 2024.7503 OCT 193.0 135.3 81.9 17.1 11.2 8.3 2024.8337 NOV 185.9 134.7 79.7 16.5 11.3 8.3 2024.9170 DEC 181.4 133.7 77.1 16.5 11.4 8.2 2025.0003 JAN 179.1 132.9 76.2 16.4 11.6 8.3 2025.0837 FEB 175.9 131.3 74.0 17.2 11.7 8.1 2025.1670 MAR 171.7 128.9 71.0 17.2 11.9 8.1 2025.2503 APR 163.2 126.7 68.9 16.9 12.1 8.1 2025.3337 MAY 159.0 125.2 67.7 17.1 12.4 8.4 2025.4170 JUN 159.2 123.8 67.2 17.8 12.7 8.6 2025.5003 JUL 158.7 121.7 67.6 18.6 13.0 8.9 2025.5837 AUG 160.0 119.4 67.0 19.4 13.1 8.9 2025.6670 SEP 163.3 117.6 65.2 20.2 13.3 8.8 2025.7503 OCT 164.9 116.3 64.2 20.5 13.6 8.9 2025.8337 NOV 162.7 114.6 63.4 20.7 13.7 8.8 2025.9170 DEC 162.3 112.2 59.5 21.3 13.9 8.7 2026.0003 JAN 162.6 109.5 55.3 22.0 14.1 8.7 2026.0837 FEB 159.1 107.3 52.9 22.1 14.3 8.6 2026.1670 MAR 154.2 105.7 51.6 22.0 14.6 9.0 2026.2503 APR 149.0 104.2 49.5 22.3 14.9 9.5 2026.3337 MAY 144.7 102.5 48.6 22.7 15.3 10.5 2026.4170 JUN 142.7 100.4 47.4 22.8 15.5 11.1 2026.5003 JUL 140.1 98.0 45.1 22.2 15.6 11.3 2026.5837 AUG 135.4 95.5 42.6 21.3 15.7 11.5 2026.6670 SEP 132.3 92.7 40.8 20.9 15.7 11.8 2026.7503 OCT 130.8 89.7 39.7 21.5 15.7 11.6 2026.8337 NOV 129.2 87.0 39.6 21.6 15.8 11.6 2026.9170 DEC 125.3 84.2 37.6 21.8 15.9 11.5 2027.0003 JAN 121.5 81.7 36.0 22.0 15.9 11.3 2027.0837 FEB 119.3 79.8 35.5 21.5 15.8 11.2 2027.1670 MAR 119.6 77.7 33.7 21.3 15.4 11.1 2027.2503 APR 121.0 75.5 29.7 21.4 15.1 10.6 2027.3337 MAY 122.1 73.3 26.5 21.5 14.8 10.0 2027.4170 JUN 122.4 71.2 24.9 22.0 14.5 9.1 2027.5003 JUL 120.7 68.7 22.7 22.5 14.2 8.1 2027.5837 AUG 118.8 66.2 20.0 22.8 13.8 7.7 2027.6670 SEP 116.3 64.1 18.4 23.2 13.7 7.4 2027.7503 OCT 112.7 62.1 17.2 23.5 13.7 7.5 2027.8337 NOV 108.9 60.1 16.2 23.4 13.6 7.7 2027.9170 DEC 105.8 57.7 13.7 23.1 13.5 8.3 2028.0003 JAN 104.4 55.7 11.8 22.5 13.5 9.0 2028.0837 FEB 102.6 54.1 10.8 21.9 13.6 8.8 2028.1670 MAR 98.9 52.5 10.4 21.8 13.8 8.4 2028.2503 APR 94.8 50.6 10.9 21.6 13.9 7.8 2028.3337 MAY 90.6 48.5 11.4 21.4 14.1 7.2 2028.4170 JUN 86.4 46.7 11.5 21.0 14.2 7.1 2028.5003 JUL 84.4 45.5 11.3 20.4 14.2 7.5 2028.5837 AUG 82.6 44.0 11.8 19.7 14.1 7.9 2028.6670 SEP 80.3 42.0 12.4 19.9 13.9 8.3 2028.7503 OCT 76.6 39.9 10.9 19.9 13.6 8.2 2028.8337 NOV 73.4 38.5 10.3 19.6 13.5 8.2 2028.9170 DEC 72.1 37.2 11.1 19.3 13.4 8.1 2029.0003 JAN 68.9 35.4 10.9 18.8 13.4 8.2 2029.0837 FEB 65.0 33.7 10.5 18.0 13.3 8.1 2029.1670 MAR 62.3 32.0 9.2 17.1 13.2 7.9 2029.2503 APR 60.8 30.2 7.9 17.3 12.9 7.3 2029.3337 MAY 58.8 28.5 7.8 17.4 12.8 7.0 2029.4170 JUN 56.9 27.1 7.8 17.5 12.7 6.8 2029.5003 JUL 55.2 25.9 7.5 17.5 12.7 6.6 2029.5837 AUG 52.9 24.6 7.5 17.6 12.7 6.7 2029.6670 SEP 50.4 23.2 7.3 17.9 12.6 6.5 2029.7503 OCT 47.3 21.9 6.1 18.0 12.6 6.3 2029.8337 NOV 42.9 20.7 5.6 17.7 12.4 6.3 2029.9170 DEC 38.5 19.2 5.1 17.5 12.1 6.1 2030.0003 JAN 35.7 17.4 4.3 16.5 11.8 6.0 2030.0837 FEB 33.1 15.9 3.3 15.1 11.5 5.9 2030.1670 MAR 32.3 14.7 2.7 14.0 11.1 5.9 2030.2503 APR 31.8 13.7 2.3 14.2 10.8 6.0 2030.3337 MAY 31.1 12.8 2.1 13.8 10.4 6.0 2030.4170 JUN 30.4 12.0 1.9 13.4 10.0 5.9 2030.5003 JUL 27.9 11.1 1.8 13.0 9.7 5.8 2030.5837 AUG 24.8 10.3 1.5 12.7 9.4 5.7 2030.6670 SEP 22.9 9.5 0.7 11.9 9.2 5.8 2030.7503 OCT 21.4 8.8 0.4 11.4 8.9 5.2 2030.8337 NOV 19.7 8.1 0.5 11.2 8.7 4.9 2030.9170 DEC 19.5 8.2 0.5 11.2 8.7 4.9 2031.0003 JAN 20.4 9.0 1.2 11.4 8.7 4.6 2031.0837 FEB 22.1 10.2 1.7 11.7 8.9 4.6 2031.1670 MAR 23.8 11.4 2.0 11.8 9.0 4.5 2031.2503 APR 26.3 12.5 2.6 12.0 9.0 4.2 2031.3337 MAY 29.1 13.7 2.8 12.1 9.1 3.9 2031.4170 JUN 33.6 15.4 3.4 12.2 9.2 3.8 2031.5003 JUL 37.0 17.2 4.5 12.3 9.2 3.7 2031.5837 AUG 40.6 19.1 5.1 12.6 9.4 3.6 2031.6670 SEP 46.0 21.3 5.7 12.9 9.7 3.6 2031.7503 OCT 52.9 23.6 6.1 13.3 10.0 3.8 2031.8337 NOV 63.0 26.6 6.1 13.8 10.3 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 176.7 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 231.0 127.1 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 241.7 141.1 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 260.4 150.2 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 75.9 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 163.8 109.2 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 115.9 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 98.1 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 13.4 22.1 14.2 8.1 2039.3337 MAY 86.4 51.3 13.7 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