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% 2021.4170 JUN 32.9 28.2 23.7 7.9 7.1 6.6 2021.5003 JUL 41.5 31.5 22.5 8.1 7.3 6.4 2021.5837 AUG 50.7 35.7 23.2 8.7 7.5 6.4 2021.6670 SEP 58.9 40.1 25.7 9.1 7.7 6.9 2021.7503 OCT 67.5 44.8 29.4 10.3 7.8 7.0 2021.8337 NOV 78.2 49.3 32.0 10.9 7.9 6.8 2021.9170 DEC 89.8 53.4 33.3 11.2 8.1 6.4 2022.0003 JAN 100.6 58.2 34.5 11.5 8.3 6.5 2022.0837 FEB 110.6 63.2 36.6 12.2 8.6 7.0 2022.1670 MAR 121.4 67.8 37.9 13.1 9.1 7.4 2022.2503 APR 133.1 72.6 40.2 13.9 9.6 7.6 2022.3337 MAY 140.6 77.5 42.3 14.6 10.0 7.9 2022.4170 JUN 146.6 82.8 44.9 15.0 10.3 7.5 2022.5003 JUL 156.7 87.5 47.3 14.7 10.4 7.0 2022.5837 AUG 164.8 90.5 47.8 14.9 10.5 6.8 2022.6670 SEP 171.8 93.3 49.2 14.8 10.6 6.6 2022.7503 OCT 181.7 96.6 50.7 14.2 10.8 6.5 2022.8337 NOV 194.1 100.2 52.1 14.5 11.0 6.1 2022.9170 DEC 204.7 104.7 52.2 14.9 11.1 5.8 2023.0003 JAN 212.9 108.9 51.2 15.0 11.3 5.5 2023.0837 FEB 219.0 112.4 50.9 15.5 11.5 5.2 2023.1670 MAR 224.4 115.7 51.8 15.5 11.5 5.1 2023.2503 APR 230.4 119.0 54.8 15.7 11.5 5.1 2023.3337 MAY 235.7 121.9 55.9 16.6 11.4 4.9 2023.4170 JUN 237.7 124.3 55.0 16.7 11.3 4.8 2023.5003 JUL 236.3 126.3 56.4 16.4 11.4 5.3 2023.5837 AUG 234.2 128.3 58.9 16.2 11.6 5.9 2023.6670 SEP 235.5 130.6 62.3 15.9 11.6 6.4 2023.7503 OCT 237.5 132.4 62.8 15.4 11.5 6.5 2023.8337 NOV 238.4 134.2 64.5 15.4 11.5 6.7 2023.9170 DEC 237.3 135.3 68.2 15.2 11.5 6.8 2024.0003 JAN 236.8 135.0 68.3 14.8 11.5 6.9 2024.0837 FEB 232.8 134.5 70.1 15.3 11.7 7.6 2024.1670 MAR 228.6 134.6 73.5 15.7 11.4 8.0 2024.2503 APR 225.3 135.8 73.9 16.1 11.1 7.3 2024.3337 MAY 223.2 137.0 71.4 16.9 11.0 7.5 2024.4170 JUN 222.2 137.3 68.3 18.3 11.2 7.8 2024.5003 JUL 221.4 137.6 67.6 19.5 11.4 8.1 2024.5837 AUG 221.1 138.4 68.1 20.2 11.6 8.1 2024.6670 SEP 221.4 139.4 69.7 21.3 11.9 8.1 2024.7503 OCT 222.0 139.7 68.3 21.7 11.9 7.7 2024.8337 NOV 220.1 139.0 66.2 21.0 12.0 7.7 2024.9170 DEC 218.7 138.3 65.6 20.9 12.0 7.5 2025.0003 JAN 217.8 137.9 66.9 20.1 12.0 7.1 2025.0837 FEB 216.6 136.7 67.8 18.1 11.9 6.6 2025.1670 MAR 214.2 135.0 67.1 16.5 12.0 6.5 2025.2503 APR 212.1 133.5 67.1 16.3 12.3 6.7 2025.3337 MAY 208.8 132.3 66.9 16.6 12.6 7.1 2025.4170 JUN 203.8 131.0 66.5 16.9 12.7 7.5 2025.5003 JUL 200.0 129.0 66.8 17.3 12.7 7.7 2025.5837 AUG 196.7 126.9 65.0 18.0 12.6 7.3 2025.6670 SEP 197.1 125.4 63.8 18.3 12.6 7.2 2025.7503 OCT 196.3 124.2 64.0 18.6 12.7 7.7 2025.8337 NOV 191.9 122.5 63.6 18.5 12.7 7.5 2025.9170 DEC 189.4 120.1 58.9 17.9 12.8 7.4 2026.0003 JAN 187.9 117.7 57.3 17.0 12.9 7.3 2026.0837 FEB 183.3 115.5 57.9 16.2 12.9 7.2 2026.1670 MAR 177.7 113.4 54.6 16.7 13.2 7.6 2026.2503 APR 171.8 111.3 51.1 17.0 13.4 8.1 2026.3337 MAY 166.3 109.3 49.4 17.1 13.6 8.9 2026.4170 JUN 162.0 107.1 48.4 17.3 13.8 9.5 2026.5003 JUL 159.0 104.8 46.7 17.7 14.0 9.7 2026.5837 AUG 153.9 102.4 44.8 19.0 14.2 10.0 2026.6670 SEP 145.5 99.5 43.9 20.1 14.2 10.4 2026.7503 OCT 138.2 96.5 44.0 20.8 14.3 10.8 2026.8337 NOV 136.6 93.4 44.1 20.9 14.5 11.4 2026.9170 DEC 134.8 90.3 42.3 20.5 14.6 11.0 2027.0003 JAN 130.6 87.7 40.7 19.9 14.6 10.4 2027.0837 FEB 126.5 85.8 41.0 19.1 14.6 9.9 2027.1670 MAR 122.3 83.7 39.5 18.4 14.3 9.5 2027.2503 APR 117.5 81.5 37.3 18.5 14.0 9.0 2027.3337 MAY 115.8 79.2 35.7 18.4 13.6 8.3 2027.4170 JUN 116.6 76.9 34.2 18.5 13.2 7.1 2027.5003 JUL 115.1 73.8 31.7 18.6 12.7 5.9 2027.5837 AUG 113.6 71.0 28.4 18.6 12.2 5.5 2027.6670 SEP 111.1 68.9 25.5 18.7 12.0 5.2 2027.7503 OCT 107.5 66.5 22.8 18.8 11.9 5.0 2027.8337 NOV 104.0 64.3 20.0 18.4 11.6 4.8 2027.9170 DEC 100.3 62.1 17.5 17.7 11.4 4.9 2028.0003 JAN 99.3 60.4 15.9 17.1 11.3 5.3 2028.0837 FEB 98.1 58.9 14.6 16.5 11.4 5.8 2028.1670 MAR 94.7 57.4 13.5 16.5 11.6 6.1 2028.2503 APR 90.9 55.8 13.5 16.4 11.7 5.5 2028.3337 MAY 86.7 53.7 13.3 16.8 12.1 5.1 2028.4170 JUN 87.0 51.8 12.4 17.2 12.3 5.1 2028.5003 JUL 87.4 50.8 11.9 17.7 12.5 5.6 2028.5837 AUG 84.9 49.7 11.4 18.2 12.4 6.2 2028.6670 SEP 80.1 47.3 11.1 18.5 12.4 6.6 2028.7503 OCT 75.5 44.7 11.7 18.6 12.2 6.6 2028.8337 NOV 70.9 42.6 11.8 18.4 12.2 6.8 2028.9170 DEC 68.0 40.7 10.8 18.2 12.3 6.9 2029.0003 JAN 66.2 38.4 9.5 17.9 12.5 7.2 2029.0837 FEB 64.6 36.2 8.9 17.3 12.6 7.3 2029.1670 MAR 62.4 34.1 7.3 16.8 12.6 7.3 2029.2503 APR 60.7 32.0 5.6 17.1 12.4 7.2 2029.3337 MAY 59.0 30.2 5.3 17.2 12.2 7.1 2029.4170 JUN 57.1 28.7 5.3 17.3 12.1 6.9 2029.5003 JUL 55.2 27.6 5.2 17.3 12.1 6.5 2029.5837 AUG 53.3 26.4 5.2 17.5 12.2 6.4 2029.6670 SEP 50.7 25.1 4.4 17.9 12.3 6.6 2029.7503 OCT 47.8 23.8 3.4 17.8 12.2 6.5 2029.8337 NOV 43.7 22.7 2.9 17.5 12.0 6.4 2029.9170 DEC 38.6 21.2 2.7 17.2 11.8 6.2 2030.0003 JAN 35.0 19.5 2.0 16.2 11.3 6.2 2030.0837 FEB 33.3 17.9 1.4 14.7 10.8 6.2 2030.1670 MAR 32.4 16.6 1.0 13.4 10.4 6.2 2030.2503 APR 31.9 15.6 0.8 13.4 10.0 6.3 2030.3337 MAY 31.2 14.6 0.6 13.1 9.6 6.4 2030.4170 JUN 30.2 13.5 0.4 12.7 9.3 6.2 2030.5003 JUL 28.2 12.5 0.3 12.5 9.1 6.0 2030.5837 AUG 25.5 11.6 0.2 12.2 8.9 5.7 2030.6670 SEP 23.6 10.8 0.0 11.4 8.6 5.2 2030.7503 OCT 21.8 10.1 0.0 10.9 8.4 4.7 2030.8337 NOV 19.3 9.4 0.0 10.7 8.1 4.3 2030.9170 DEC 19.2 9.4 0.0 10.7 8.2 4.3 2031.0003 JAN 20.1 10.0 0.7 11.0 8.3 4.2 2031.0837 FEB 21.9 11.1 1.3 11.3 8.5 4.2 2031.1670 MAR 23.5 12.2 1.7 11.4 8.6 4.1 2031.2503 APR 26.1 13.2 2.3 11.7 8.7 3.8 2031.3337 MAY 28.9 14.3 2.5 11.8 8.8 3.7 2031.4170 JUN 33.4 15.9 3.2 12.0 8.9 3.6 2031.5003 JUL 36.9 17.6 4.4 12.1 9.1 3.5 2031.5837 AUG 40.5 19.4 5.0 12.5 9.3 3.4 2031.6670 SEP 45.9 21.5 5.6 12.8 9.6 3.5 2031.7503 OCT 52.8 23.8 6.1 13.2 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