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% 2019.9173 DEC 4.0 2.7 2.1 5.7 5.5 5.2 2020.0007 JAN 6.9 3.8 2.2 5.9 5.6 5.0 2020.0840 FEB 9.1 4.9 2.2 6.0 5.6 5.0 2020.1673 MAR 11.7 5.8 2.4 6.0 5.5 4.9 2020.2507 APR 14.9 6.7 2.5 6.1 5.6 4.9 2020.3340 MAY 18.8 7.7 2.3 6.2 5.6 4.8 2020.4173 JUN 22.4 9.2 1.8 6.6 5.6 4.5 2020.5007 JUL 25.7 10.9 1.4 7.1 5.6 4.3 2020.5840 AUG 30.2 12.4 1.6 7.2 5.6 4.1 2020.6673 SEP 36.0 14.0 2.1 7.4 5.8 4.1 2020.7507 OCT 44.6 15.9 1.3 7.5 6.0 4.2 2020.8340 NOV 51.6 18.0 0.0 7.6 6.0 4.4 2020.9173 DEC 56.6 20.1 0.0 7.5 5.9 4.1 2021.0007 JAN 64.1 22.2 0.0 7.5 5.8 3.8 2021.0840 FEB 72.8 25.0 0.0 7.5 5.8 3.7 2021.1673 MAR 80.9 28.1 0.0 8.0 5.7 3.2 2021.2507 APR 91.0 31.3 0.0 8.9 5.8 3.0 2021.3340 MAY 102.9 34.8 0.0 9.8 6.1 3.0 2021.4173 JUN 111.7 38.4 0.0 10.0 6.2 3.0 2021.5007 JUL 118.2 42.4 0.0 9.9 6.4 3.0 2021.5840 AUG 124.6 46.8 0.0 9.4 6.4 3.0 2021.6673 SEP 131.5 51.3 0.0 8.8 6.4 3.2 2021.7507 OCT 138.7 55.4 1.2 8.2 6.3 3.4 2021.8340 NOV 146.5 59.4 3.2 8.4 6.4 3.5 2021.9173 DEC 154.6 64.0 4.7 9.3 6.6 3.9 2022.0007 JAN 163.6 68.0 6.2 10.5 7.0 4.6 2022.0840 FEB 173.7 72.0 7.1 10.9 7.5 5.2 2022.1673 MAR 182.9 76.4 9.6 10.8 7.9 5.4 2022.2507 APR 188.1 80.1 10.7 11.0 8.2 5.7 2022.3340 MAY 189.2 83.7 12.2 11.6 8.4 5.4 2022.4173 JUN 192.2 87.3 14.1 12.2 8.5 4.9 2022.5007 JUL 196.7 90.2 15.3 12.4 8.7 4.9 2022.5840 AUG 202.3 93.1 17.5 12.9 9.0 4.9 2022.6673 SEP 211.0 96.4 17.6 13.7 9.4 5.1 2022.7507 OCT 216.2 99.0 16.4 14.4 9.6 4.8 2022.8340 NOV 217.8 101.3 16.4 14.7 9.7 4.4 2022.9173 DEC 222.6 104.3 15.8 14.6 10.0 4.1 2023.0007 JAN 229.1 107.1 16.1 14.2 10.3 4.0 2023.0840 FEB 233.2 108.7 17.6 14.0 10.3 3.9 2023.1673 MAR 236.3 109.6 16.3 14.3 10.2 3.9 2023.2507 APR 239.7 110.1 13.9 15.1 10.1 3.6 2023.3340 MAY 242.5 111.3 12.4 15.3 10.1 3.5 2023.4173 JUN 244.5 112.5 12.7 15.0 10.3 4.1 2023.5007 JUL 245.9 113.6 15.6 14.9 10.5 4.7 2023.5840 AUG 247.7 115.1 17.8 14.5 10.5 5.0 2023.6673 SEP 246.9 115.5 18.1 13.9 10.3 5.0 2023.7507 OCT 245.7 116.1 20.0 13.7 10.2 5.1 2023.8340 NOV 247.1 117.0 22.5 13.8 10.3 5.2 2023.9173 DEC 246.9 117.0 25.0 13.5 10.2 5.1 2024.0007 JAN 242.5 117.5 28.6 13.3 10.0 5.4 2024.0840 FEB 237.7 118.6 33.4 12.9 9.7 5.7 2024.1673 MAR 233.2 120.0 38.4 12.9 9.3 5.6 2024.2507 APR 230.0 120.8 42.0 13.1 9.1 5.5 2024.3340 MAY 228.4 120.9 44.5 14.3 9.2 5.3 2024.4173 JUN 227.7 121.4 47.6 15.2 9.2 5.2 2024.5007 JUL 226.4 122.6 51.1 15.7 9.3 5.6 2024.5840 AUG 224.6 123.5 55.0 16.6 9.4 5.7 2024.6673 SEP 224.2 124.1 57.2 16.8 9.4 5.6 2024.7507 OCT 222.8 124.4 57.3 16.3 9.5 5.8 2024.8340 NOV 222.9 124.4 58.2 16.3 9.7 6.0 2024.9173 DEC 221.6 124.6 61.2 15.4 9.6 6.1 2025.0007 JAN 217.8 123.5 63.5 13.8 9.5 5.8 2025.0840 FEB 212.0 120.3 64.8 13.8 9.7 5.7 2025.1673 MAR 208.2 117.5 65.6 14.2 10.0 5.7 2025.2507 APR 204.0 115.3 62.8 14.4 10.2 6.0 2025.3340 MAY 198.0 113.1 59.8 15.2 10.5 6.6 2025.4173 JUN 192.9 110.6 57.9 15.7 10.8 6.9 2025.5007 JUL 186.8 107.6 55.1 16.3 10.6 6.7 2025.5840 AUG 181.5 105.6 52.9 16.6 10.6 6.9 2025.6673 SEP 178.0 104.6 52.8 17.0 10.8 7.3 2025.7507 OCT 172.9 103.1 52.6 17.0 10.9 7.1 2025.8340 NOV 167.3 100.1 49.8 16.3 10.9 6.9 2025.9173 DEC 163.1 97.3 47.9 15.3 10.8 6.8 2026.0007 JAN 158.8 95.5 47.1 14.0 10.9 6.7 2026.0840 FEB 155.1 93.6 43.8 13.5 11.3 7.1 2026.1673 MAR 152.0 91.7 40.7 14.3 11.7 7.6 2026.2507 APR 148.5 89.9 39.1 15.0 12.0 8.5 2026.3340 MAY 143.1 87.7 37.5 15.3 12.2 8.2 2026.4173 JUN 136.2 85.5 35.3 14.9 12.4 8.5 2026.5007 JUL 131.6 83.8 33.4 15.9 12.6 9.0 2026.5840 AUG 127.8 81.8 32.5 17.3 12.7 9.3 2026.6673 SEP 123.9 79.0 31.9 18.1 12.8 9.9 2026.7507 OCT 121.0 75.4 31.8 18.4 13.0 9.3 2026.8340 NOV 116.5 71.4 29.8 18.3 13.3 9.2 2026.9173 DEC 112.2 67.8 27.9 18.4 13.5 8.9 2027.0007 JAN 111.1 65.4 27.8 18.3 13.6 8.5 2027.0840 FEB 113.0 63.3 26.8 18.5 13.5 8.4 2027.1673 MAR 114.4 61.5 24.2 18.9 13.4 8.3 2027.2507 APR 115.2 60.0 20.8 19.2 13.2 8.0 2027.3340 MAY 115.3 58.7 18.7 19.7 12.9 7.0 2027.4173 JUN 113.1 56.6 16.8 20.0 12.4 6.0 2027.5007 JUL 111.8 54.6 15.1 20.3 12.0 5.6 2027.5840 AUG 109.5 52.7 13.6 20.6 11.8 5.5 2027.6673 SEP 105.0 50.3 12.0 20.8 11.7 5.4 2027.7507 OCT 100.9 48.3 10.5 20.6 11.5 5.4 2027.8340 NOV 98.8 46.7 8.7 19.9 11.3 5.3 2027.9173 DEC 98.9 45.6 7.4 18.9 11.0 5.5 2028.0007 JAN 98.7 44.8 6.6 18.2 11.0 5.8 2028.0840 FEB 96.0 43.6 6.2 18.0 11.2 5.9 2028.1673 MAR 92.2 42.4 6.6 17.8 11.4 5.4 2028.2507 APR 87.2 40.5 7.0 17.7 11.7 4.9 2028.3340 MAY 82.2 38.7 6.4 17.6 12.0 5.0 2028.4173 JUN 80.6 37.8 6.5 18.0 12.2 5.5 2028.5007 JUL 79.4 36.8 7.1 18.4 12.2 6.1 2028.5840 AUG 75.7 34.5 7.5 18.7 12.1 6.5 2028.6673 SEP 71.4 32.3 7.1 18.8 12.0 6.5 2028.7507 OCT 69.9 31.1 6.6 18.6 12.0 6.7 2028.8340 NOV 69.0 30.0 6.8 18.4 12.1 6.8 2028.9173 DEC 65.8 28.5 6.4 18.1 12.5 7.2 2029.0007 JAN 61.1 27.0 5.3 17.6 12.7 7.5 2029.0840 FEB 56.6 25.4 4.0 16.7 12.7 7.5 2029.1673 MAR 53.6 23.6 2.5 16.9 12.5 7.4 2029.2507 APR 50.4 22.0 2.0 16.9 12.1 7.1 2029.3340 MAY 48.1 21.0 2.3 16.9 11.8 6.7 2029.4173 JUN 46.4 20.1 2.5 16.9 11.8 6.2 2029.5007 JUL 43.1 18.9 2.0 17.2 11.8 6.1 2029.5840 AUG 38.2 17.7 0.6 17.6 12.0 6.5 2029.6673 SEP 35.4 16.7 0.0 17.6 11.9 6.6 2029.7507 OCT 34.6 16.0 0.0 17.3 11.7 6.5 2029.8340 NOV 32.6 14.9 0.0 17.0 11.5 6.5 2029.9173 DEC 29.8 13.5 0.0 15.9 11.0 6.4 2030.0007 JAN 27.4 12.5 0.0 14.4 10.3 6.4 2030.0840 FEB 26.0 11.7 0.0 13.1 9.8 6.3 2030.1673 MAR 25.8 11.2 0.0 13.1 9.4 6.1 2030.2507 APR 25.2 10.3 0.0 12.8 9.1 6.0 2030.3340 MAY 23.9 9.1 0.0 12.5 8.9 5.9 2030.4173 JUN 22.2 8.3 0.0 12.3 8.7 5.7 2030.5007 JUL 19.9 7.7 0.0 12.0 8.5 5.3 2030.5840 AUG 17.9 7.3 0.0 11.2 8.1 4.7 2030.6673 SEP 16.6 6.8 0.0 10.7 7.9 4.2 2030.7507 OCT 14.5 6.5 0.0 10.5 7.8 4.0 2030.8340 NOV 14.9 6.7 0.0 10.6 7.9 4.0 2030.9173 DEC 16.2 7.6 0.7 10.8 8.0 3.9 2031.0007 JAN 18.3 8.9 1.3 11.2 8.2 3.9 2031.0840 FEB 20.4 10.3 1.7 11.4 8.4 3.9 2031.1673 MAR 23.3 11.5 2.3 11.6 8.5 3.6 2031.2507 APR 26.5 12.9 2.5 11.8 8.6 3.5 2031.3340 MAY 31.4 14.7 3.2 11.9 8.8 3.4 2031.4173 JUN 35.3 16.6 4.3 12.1 8.9 3.4 2031.5007 JUL 39.3 18.7 5.0 12.4 9.2 3.3 2031.5840 AUG 45.1 21.0 5.6 12.8 9.5 3.4 2031.6673 SEP 52.4 23.5 6.1 13.2 9.9 3.8 2031.7507 OCT 63.1 26.6 6.1 13.8 10.4 4.2 2031.8340 NOV 71.9 29.9 6.3 14.6 10.6 4.5 2031.9173 DEC 78.8 33.1 7.3 15.7 10.9 4.6 2032.0007 JAN 88.8 36.7 7.3 16.1 11.1 4.8 2032.0840 FEB 99.7 40.7 7.3 16.3 11.3 5.0 2032.1673 MAR 109.4 44.7 8.0 16.9 11.4 5.0 2032.2507 APR 121.3 49.1 8.2 18.0 11.6 5.2 2032.3340 MAY 135.7 53.9 8.9 18.9 11.9 5.4 2032.4173 JUN 145.7 58.8 10.0 19.1 12.1 5.6 2032.5007 JUL 152.6 64.1 11.7 19.2 12.3 5.8 2032.5840 AUG 159.7 69.5 13.3 19.0 12.6 6.0 2032.6673 SEP 167.7 74.8 15.6 18.6 12.7 6.1 2032.7507 OCT 176.7 80.0 16.9 18.5 12.7 6.1 2032.8340 NOV 186.4 85.3 17.0 18.9 12.8 6.1 2032.9173 DEC 195.5 91.2 19.1 18.8 12.9 6.3 2033.0007 JAN 203.4 97.0 20.9 17.8 13.0 6.5 2033.0840 FEB 211.7 102.5 22.7 17.9 13.2 6.7 2033.1673 MAR 216.9 107.9 24.6 18.4 13.4 7.0 2033.2507 APR 223.4 113.6 25.4 19.1 13.7 7.0 2033.3340 MAY 224.9 118.9 26.5 19.6 14.2 7.0 2033.4173 JUN 225.7 123.3 27.6 20.3 14.5 7.0 2033.5007 JUL 231.0 127.1 28.4 20.3 14.5 7.2 2033.5840 AUG 233.8 130.6 29.3 20.3 14.5 7.6 2033.6673 SEP 236.3 134.3 29.4 20.5 14.6 8.0 2033.7507 OCT 239.2 137.7 28.9 20.8 14.8 8.0 2033.8340 NOV 241.7 141.0 28.5 21.2 14.8 8.0 2033.9173 DEC 248.2 144.4 29.4 21.3 14.6 8.3 2034.0007 JAN 255.6 147.4 30.6 21.4 14.6 8.6 2034.0840 FEB 260.4 150.2 32.8 21.6 14.6 8.5 2034.1673 MAR 264.8 153.0 36.1 22.0 14.5 8.4 2034.2507 APR 269.5 155.5 38.1 22.7 14.4 8.6 2034.3340 MAY 272.7 157.2 40.4 22.4 14.1 8.6 2034.4173 JUN 274.4 158.0 44.2 21.3 13.8 8.6 2034.5007 JUL 275.1 158.0 48.5 20.6 13.7 8.4 2034.5840 AUG 276.4 158.8 52.8 20.1 13.6 8.1 2034.6673 SEP 276.2 160.2 54.7 19.7 13.5 7.7 2034.7507 OCT 275.2 161.0 56.7 19.6 13.5 7.5 2034.8340 NOV 276.2 161.2 60.3 19.3 13.5 7.8 2034.9173 DEC 275.3 160.2 62.7 19.1 13.7 7.8 2035.0007 JAN 269.5 158.5 66.2 18.9 13.9 7.6 2035.0840 FEB 263.0 157.1 68.8 18.9 14.0 7.5 2035.1673 MAR 257.3 156.7 71.6 19.5 13.9 7.3 2035.2507 APR 253.6 156.8 73.6 20.4 14.0 7.1 2035.3340 MAY 251.7 156.5 73.3 22.0 14.4 7.1 2035.4173 JUN 249.8 155.9 72.5 23.4 14.6 7.0 2035.5007 JUL 248.7 155.5 73.6 24.0 14.8 7.2 2035.5840 AUG 246.7 154.9 76.8 25.1 15.1 7.3 2035.6673 SEP 244.9 154.2 76.9 25.7 15.3 7.1 2035.7507 OCT 242.7 153.3 75.2 24.9 15.3 7.1 2035.8340 NOV 241.9 152.0 74.2 24.8 15.4 6.9 2035.9173 DEC 239.5 150.6 75.1 24.0 15.3 6.4 2036.0007 JAN 234.9 148.4 75.8 22.2 15.3 6.1 2036.0840 FEB 230.5 145.3 73.9 22.5 15.5 6.2 2036.1673 MAR 226.5 142.7 73.2 23.2 15.6 6.4 2036.2507 APR 222.0 140.7 74.9 23.2 15.7 6.6 2036.3340 MAY 216.0 138.6 76.5 22.7 15.7 6.9 2036.4173 JUN 210.7 135.7 74.5 22.0 15.6 7.4 2036.5007 JUL 205.8 132.8 71.2 21.9 15.7 7.6 2036.5840 AUG 202.0 130.4 69.5 22.7 15.9 7.9 2036.6673 SEP 200.2 128.3 68.9 23.7 16.2 8.4 2036.7507 OCT 194.9 125.6 65.7 23.9 16.4 8.7 2036.8340 NOV 191.9 122.7 58.8 23.8 16.6 9.1 2036.9173 DEC 189.9 119.9 57.2 23.8 16.6 9.5 2037.0007 JAN 185.1 117.4 59.1 23.4 16.5 9.9 2037.0840 FEB 179.7 115.4 57.6 22.5 16.5 10.3 2037.1673 MAR 174.1 113.6 54.5 22.7 16.4 10.7 2037.2507 APR 168.6 111.6 52.9 23.0 16.5 11.2 2037.3340 MAY 163.8 109.3 51.6 23.0 16.6 11.6 2037.4173 JUN 160.3 106.4 49.1 22.4 16.7 11.8 2037.5007 JUL 154.9 103.5 46.5 21.5 16.5 11.9 2037.5840 AUG 146.1 100.2 45.0 21.2 16.4 11.8 2037.6673 SEP 138.4 96.8 44.3 21.7 16.2 11.5 2037.7507 OCT 136.9 93.8 44.5 21.7 16.0 11.4 2037.8340 NOV 135.5 91.0 43.0 22.1 16.1 11.5 2037.9173 DEC 131.3 88.5 40.6 22.5 16.2 11.3 2038.0007 JAN 126.7 86.1 40.9 22.3 16.2 11.1 2038.0840 FEB 121.9 83.4 39.8 22.3 16.0 10.9 2038.1673 MAR 116.7 80.6 37.9 22.7 15.8 10.7 2038.2507 APR 115.8 78.1 36.5 22.9 15.5 10.7 2038.3340 MAY 116.7 75.5 34.0 23.4 15.3 10.5 2038.4173 JUN 115.2 72.8 31.6 24.0 15.1 10.2 2038.5007 JUL 113.7 70.1 27.9 24.7 14.9 10.1 2038.5840 AUG 111.2 67.9 24.9 25.3 14.8 10.0 2038.6673 SEP 107.6 66.0 22.9 25.5 14.8 10.2 2038.7507 OCT 103.7 64.0 20.0 25.3 14.7 10.5 2038.8340 NOV 100.4 61.7 17.6 24.8 14.5 10.3 2038.9173 DEC 99.3 59.6 16.1 23.9 14.3 10.0 2039.0007 JAN 98.1 57.6 14.9 23.0 14.1 9.4 2039.0840 FEB 95.1 55.6 13.6 22.5 14.2 8.8 2039.1673 MAR 91.4 53.5 13.4 22.1 14.2 8.1 2039.2507 APR 86.4 51.3 13.7 21.8 14.4 7.5 2039.3340 MAY 84.7 49.5 13.1 21.4 14.5 7.4 2039.4173 JUN 85.0 48.1 12.9 20.8 14.4 7.7 2039.5007 JUL 82.2 46.5 12.6 20.0 14.3 8.1 2039.5840 AUG 77.6 44.4 12.0 20.0 14.1 8.5 2039.6673 SEP 73.8 42.2 11.1 20.2 13.9 8.5 2039.7507 OCT 70.0 40.7 11.0 19.8 13.8 8.5 2039.8340 NOV 68.3 39.4 10.3 19.4 13.6 8.4 2039.9173 DEC 65.8 37.7 9.2 18.9 13.6 8.4 2040.0007 JAN 64.4 36.0 8.8 18.2 13.6 8.3 2040.0840 FEB 62.8 34.4 8.0 17.3 13.5 8.0 2040.1673 MAR 61.9 32.8 6.4 17.3 13.4 7.6 2040.2507 APR 60.4 31.1 5.9 17.4 13.2 7.1 2040.3340 MAY 58.5 29.7 5.9 17.5 13.1 6.7 2040.4173 JUN 56.4 28.3 5.6 17.5 13.0 6.6 2040.5007 JUL 54.1 27.0 5.4 17.7 12.8 6.5 2040.5840 AUG 51.2 25.4 4.3 18.0 12.8 6.6 2040.6673 SEP 48.1 24.0 3.4 17.9 12.6 6.5 2040.7507 OCT 43.8 22.8 2.9 17.6 12.3 6.4 2040.8340 NOV 38.5 21.2 2.8 17.3 12.1 6.4 2040.9173 DEC 34.9 19.4 2.2 16.3 11.7 6.2 2041.0007 JAN 33.1 17.6 1.6 14.9 11.2 6.1 2041.0840 FEB 32.1 16.2 1.3 13.8 10.9 6.1 2041.1673 MAR 31.6 15.0 1.1 13.9 10.5 6.1 2041.2507 APR 30.9 14.0 1.1 13.6 10.2 6.2 2041.3340 MAY 30.2 13.1 0.8 13.2 9.8 6.2 2041.4173 JUN 27.9 12.2 0.6 12.9 9.5 6.0 2041.5007 JUL 25.2 11.4 0.3 12.6 9.3 5.9 2041.5840 AUG 23.3 10.6 0.1 11.9 9.1 5.7 2041.6673 SEP 21.6 9.9 0.0 11.4 8.9 5.2