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% 2020.0837 FEB 5.0 3.2 1.7 5.8 5.6 5.3 2020.1670 MAR 7.6 4.3 1.6 5.9 5.5 5.2 2020.2503 APR 10.7 5.1 1.9 6.0 5.5 4.9 2020.3337 MAY 13.5 6.0 2.1 6.1 5.5 4.9 2020.4170 JUN 17.6 7.0 1.5 6.4 5.6 4.7 2020.5003 JUL 21.1 8.5 0.9 6.9 5.6 4.4 2020.5837 AUG 24.4 10.0 0.4 7.4 5.6 4.3 2020.6670 SEP 28.8 11.5 0.5 7.6 5.6 4.1 2020.7503 OCT 34.4 13.0 0.9 7.7 5.8 4.1 2020.8337 NOV 42.8 14.7 0.0 7.9 6.0 4.2 2020.9170 DEC 49.6 16.8 0.0 8.0 6.0 4.4 2021.0003 JAN 54.4 18.7 0.0 8.0 5.9 4.2 2021.0837 FEB 61.8 20.8 0.0 7.9 5.9 3.9 2021.1670 MAR 70.5 23.5 0.0 8.0 5.8 3.8 2021.2503 APR 78.7 26.7 0.0 8.2 5.8 3.2 2021.3337 MAY 89.1 29.8 0.0 9.1 5.9 3.0 2021.4170 JUN 101.3 33.1 0.0 9.9 6.1 2.9 2021.5003 JUL 110.4 36.7 0.0 10.0 6.2 2.9 2021.5837 AUG 117.0 40.8 0.0 9.9 6.3 2.9 2021.6670 SEP 123.5 45.2 0.0 9.4 6.4 2.9 2021.7503 OCT 130.5 49.7 0.0 8.9 6.4 3.1 2021.8337 NOV 137.8 53.8 0.0 8.3 6.3 3.3 2021.9170 DEC 145.7 57.9 1.5 8.3 6.4 3.4 2022.0003 JAN 153.8 62.6 3.7 9.2 6.6 3.8 2022.0837 FEB 162.8 66.6 5.3 10.4 7.0 4.7 2022.1670 MAR 172.9 70.6 6.2 10.8 7.5 5.2 2022.2503 APR 182.0 74.8 8.5 10.7 7.9 5.5 2022.3337 MAY 187.2 78.4 9.6 10.9 8.2 5.7 2022.4170 JUN 188.2 81.9 11.0 11.5 8.4 5.5 2022.5003 JUL 191.1 85.5 12.8 12.1 8.5 5.1 2022.5837 AUG 195.6 88.1 13.7 12.3 8.7 4.9 2022.6670 SEP 199.7 90.8 15.7 12.8 9.0 5.1 2022.7503 OCT 207.5 94.0 15.6 13.7 9.4 5.3 2022.8337 NOV 212.6 96.6 14.4 14.3 9.6 4.9 2022.9170 DEC 214.2 99.0 14.6 14.6 9.6 4.5 2023.0003 JAN 220.3 102.1 14.2 14.5 9.9 4.1 2023.0837 FEB 227.5 105.0 14.7 14.1 10.2 3.9 2023.1670 MAR 231.6 106.5 15.9 13.8 10.2 3.8 2023.2503 APR 234.6 107.3 14.5 14.1 10.1 3.8 2023.3337 MAY 238.0 107.7 12.2 14.9 10.0 3.5 2023.4170 JUN 240.9 109.0 10.7 15.0 10.0 3.4 2023.5003 JUL 243.0 110.4 11.2 14.7 10.1 3.9 2023.5837 AUG 244.7 111.9 14.4 14.6 10.3 4.5 2023.6670 SEP 246.5 113.6 16.4 14.2 10.3 4.8 2023.7503 OCT 245.8 114.1 16.9 13.6 10.1 4.9 2023.8337 NOV 244.7 114.8 19.0 13.5 10.1 5.0 2023.9170 DEC 246.1 115.7 21.5 13.5 10.2 5.1 2024.0003 JAN 245.9 115.7 24.1 13.1 10.0 5.0 2024.0837 FEB 241.8 116.4 28.0 12.9 9.9 5.3 2024.1670 MAR 237.1 117.8 33.0 12.7 9.6 5.6 2024.2503 APR 232.7 119.4 38.2 12.7 9.1 5.5 2024.3337 MAY 229.6 120.4 42.0 12.9 9.0 5.4 2024.4170 JUN 228.0 120.6 44.6 13.9 9.0 5.1 2024.5003 JUL 227.3 121.1 47.7 14.9 9.1 5.1 2024.5837 AUG 226.1 122.5 51.3 15.4 9.2 5.5 2024.6670 SEP 224.3 123.3 55.1 16.2 9.2 5.6 2024.7503 OCT 223.9 123.7 57.1 16.3 9.2 5.3 2024.8337 NOV 222.8 124.0 57.2 15.8 9.4 5.6 2024.9170 DEC 223.2 124.1 58.2 15.8 9.4 5.7 2025.0003 JAN 222.0 124.5 60.5 15.0 9.4 5.9 2025.0837 FEB 217.8 123.4 62.4 13.3 9.4 5.6 2025.1670 MAR 211.7 120.3 63.8 13.3 9.6 5.6 2025.2503 APR 207.8 117.4 62.9 13.7 10.0 5.8 2025.3337 MAY 203.6 115.0 60.7 14.0 10.2 6.0 2025.4170 JUN 197.5 112.8 57.7 15.1 10.6 6.7 2025.5003 JUL 192.4 110.2 55.8 16.0 10.8 7.1 2025.5837 AUG 186.4 107.1 52.8 16.8 10.7 6.9 2025.6670 SEP 181.7 105.1 50.7 17.2 10.7 7.1 2025.7503 OCT 178.4 104.3 50.9 17.6 11.0 7.2 2025.8337 NOV 173.3 103.0 51.0 17.6 11.0 7.1 2025.9170 DEC 167.7 100.0 48.0 16.9 11.0 6.9 2026.0003 JAN 163.5 97.3 45.9 15.9 11.0 6.7 2026.0837 FEB 159.1 95.5 45.0 14.6 11.1 6.6 2026.1670 MAR 155.5 93.5 41.5 14.1 11.5 7.1 2026.2503 APR 152.3 91.5 38.2 14.7 11.9 7.6 2026.3337 MAY 148.8 89.7 36.5 15.3 12.1 8.4 2026.4170 JUN 143.4 87.4 34.9 15.5 12.2 8.2 2026.5003 JUL 135.9 85.2 32.8 15.1 12.4 8.4 2026.5837 AUG 130.5 83.6 31.1 15.8 12.5 8.9 2026.6670 SEP 126.8 81.8 30.4 17.2 12.6 9.2 2026.7503 OCT 122.0 78.9 29.8 18.0 12.7 9.9 2026.8337 NOV 118.4 75.1 29.0 18.4 13.0 9.2 2026.9170 DEC 114.1 70.9 26.7 18.2 13.2 9.0 2027.0003 JAN 109.3 67.1 24.5 18.2 13.4 8.7 2027.0837 FEB 108.3 64.8 24.4 18.2 13.5 8.3 2027.1670 MAR 110.3 62.7 23.4 18.3 13.4 8.1 2027.2503 APR 111.8 60.9 20.4 18.8 13.3 8.1 2027.3337 MAY 112.8 59.4 17.2 19.1 13.0 7.8 2027.4170 JUN 113.1 58.1 15.6 19.5 12.8 6.8 2027.5003 JUL 111.0 56.0 13.7 19.9 12.3 5.8 2027.5837 AUG 109.7 54.1 12.2 20.2 11.9 5.5 2027.6670 SEP 107.5 52.3 10.8 20.5 11.7 5.3 2027.7503 OCT 102.9 49.9 9.1 20.8 11.7 5.3 2027.8337 NOV 98.8 48.0 7.7 20.5 11.4 5.1 2027.9170 DEC 96.7 46.5 6.2 19.7 11.1 5.1 2028.0003 JAN 96.9 45.5 5.2 18.8 11.0 5.3 2028.0837 FEB 97.0 44.8 4.6 18.1 10.9 5.7 2028.1670 MAR 94.4 43.6 4.4 17.9 11.2 6.0 2028.2503 APR 90.7 42.4 5.2 17.6 11.3 5.4 2028.3337 MAY 85.7 40.5 5.8 17.5 11.5 4.9 2028.4170 JUN 80.7 38.6 5.2 17.3 11.8 5.0 2028.5003 JUL 79.2 37.8 5.4 17.8 12.0 5.5 2028.5837 AUG 78.1 36.8 6.1 18.2 11.9 6.0 2028.6670 SEP 74.4 34.4 6.4 18.4 11.9 6.4 2028.7503 OCT 70.1 32.1 5.9 18.6 11.7 6.4 2028.8337 NOV 68.5 30.9 5.2 18.4 11.7 6.6 2028.9170 DEC 67.7 29.7 5.9 18.2 11.9 6.8 2029.0003 JAN 64.6 28.1 5.7 17.9 12.2 7.1 2029.0837 FEB 59.8 26.5 4.9 17.3 12.4 7.3 2029.1670 MAR 55.4 24.7 3.5 16.5 12.4 7.3 2029.2503 APR 52.3 23.0 2.0 16.7 12.1 7.1 2029.3337 MAY 49.2 21.5 1.6 16.7 11.8 7.0 2029.4170 JUN 46.9 20.5 1.9 16.7 11.6 6.6 2029.5003 JUL 45.3 19.7 1.9 16.8 11.5 6.1 2029.5837 AUG 42.0 18.5 1.2 17.0 11.7 6.0 2029.6670 SEP 37.4 17.4 0.0 17.4 11.7 6.3 2029.7503 OCT 35.2 16.5 0.0 17.4 11.6 6.6 2029.8337 NOV 34.5 15.9 0.0 17.1 11.5 6.6 2029.9170 DEC 32.5 14.8 0.0 16.8 11.2 6.4 2030.0003 JAN 29.8 13.4 0.0 15.7 10.7 6.4 2030.0837 FEB 27.5 12.5 0.0 14.2 10.1 6.3 2030.1670 MAR 26.2 11.7 0.0 12.9 9.7 6.2 2030.2503 APR 26.2 11.2 0.0 13.0 9.4 6.1 2030.3337 MAY 25.5 10.3 0.0 12.7 9.0 6.0 2030.4170 JUN 24.3 9.1 0.0 12.4 8.7 5.9 2030.5003 JUL 22.6 8.3 0.0 12.2 8.5 5.7 2030.5837 AUG 20.2 7.7 0.0 11.9 8.3 5.3 2030.6670 SEP 18.0 7.2 0.0 11.1 8.0 4.7 2030.7503 OCT 16.7 6.7 0.0 10.6 7.8 4.2 2030.8337 NOV 14.5 6.3 0.0 10.4 7.6 3.9 2030.9170 DEC 14.9 6.6 0.0 10.4 7.7 3.9 2031.0003 JAN 16.2 7.5 0.7 10.7 7.8 3.8 2031.0837 FEB 18.3 8.8 1.3 11.1 8.0 3.9 2031.1670 MAR 20.4 10.2 1.7 11.2 8.2 3.8 2031.2503 APR 23.3 11.4 2.3 11.5 8.4 3.6 2031.3337 MAY 26.5 12.8 2.5 11.7 8.5 3.4 2031.4170 JUN 31.4 14.6 3.2 11.9 8.7 3.4 2031.5003 JUL 35.3 16.6 4.4 12.0 8.9 3.4 2031.5837 AUG 39.3 18.7 5.0 12.4 9.1 3.3 2031.6670 SEP 45.1 21.0 5.6 12.8 9.5 3.4 2031.7503 OCT 52.4 23.5 6.1 13.2 9.9 3.7 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