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% 2020.4170 JUN 8.3 6.2 4.2 5.6 5.1 4.7 2020.5003 JUL 10.9 7.4 3.0 6.0 5.1 4.4 2020.5837 AUG 13.5 8.6 2.2 6.4 5.0 4.2 2020.6670 SEP 18.7 9.7 1.8 6.6 5.0 4.1 2020.7503 OCT 22.8 10.6 1.6 6.7 5.2 4.1 2020.8337 NOV 26.2 11.5 0.1 6.9 5.4 4.3 2020.9170 DEC 30.7 12.9 0.0 7.1 5.5 4.1 2021.0003 JAN 33.9 14.6 0.0 7.1 5.4 3.7 2021.0837 FEB 38.8 16.2 0.0 7.6 5.4 3.3 2021.1670 MAR 45.9 18.4 0.0 8.2 5.4 3.3 2021.2503 APR 54.1 21.2 0.0 8.8 5.4 2.9 2021.3337 MAY 62.2 23.7 0.0 9.9 5.6 2.7 2021.4170 JUN 71.5 26.1 0.0 10.7 5.8 2.7 2021.5003 JUL 79.1 29.4 0.0 10.9 6.0 2.6 2021.5837 AUG 85.1 33.6 0.0 10.8 6.1 2.6 2021.6670 SEP 93.6 38.0 0.0 10.3 6.1 2.6 2021.7503 OCT 102.5 42.6 0.0 9.7 6.0 2.8 2021.8337 NOV 113.0 46.8 0.2 9.1 5.9 2.9 2021.9170 DEC 124.5 50.8 2.0 8.6 6.0 3.0 2022.0003 JAN 134.9 55.6 4.3 8.6 6.2 3.4 2022.0837 FEB 143.5 59.9 6.6 9.6 6.6 4.1 2022.1670 MAR 152.8 63.6 7.1 10.0 7.0 4.7 2022.2503 APR 162.4 68.0 8.8 10.0 7.4 4.9 2022.3337 MAY 168.9 72.1 10.4 10.1 7.7 5.2 2022.4170 JUN 172.4 76.5 13.6 10.7 7.9 4.7 2022.5003 JUL 177.1 80.4 15.3 11.4 8.0 4.3 2022.5837 AUG 180.7 82.9 13.9 11.5 8.2 4.2 2022.6670 SEP 185.6 85.5 13.8 12.1 8.6 4.4 2022.7503 OCT 194.0 88.6 15.9 13.0 9.1 4.7 2022.8337 NOV 201.1 91.7 17.9 13.7 9.2 4.3 2022.9170 DEC 206.0 95.5 20.0 14.0 9.3 4.0 2023.0003 JAN 213.3 99.9 23.8 14.1 9.7 3.8 2023.0837 FEB 221.2 103.6 27.3 14.1 10.0 3.6 2023.1670 MAR 225.9 106.1 29.7 14.4 10.0 3.5 2023.2503 APR 229.5 107.9 30.1 14.8 10.0 3.5 2023.3337 MAY 233.4 109.3 30.3 15.7 9.9 3.4 2023.4170 JUN 236.7 111.2 29.6 15.9 9.9 3.4 2023.5003 JUL 239.5 113.4 29.9 15.4 10.1 3.9 2023.5837 AUG 242.7 115.8 32.8 15.2 10.3 4.4 2023.6670 SEP 246.0 118.2 35.2 14.7 10.2 4.7 2023.7503 OCT 245.2 119.5 36.7 14.1 10.0 4.6 2023.8337 NOV 244.3 120.9 39.5 14.0 10.0 4.8 2023.9170 DEC 246.0 122.0 42.1 13.8 10.1 5.0 2024.0003 JAN 246.3 122.1 44.4 13.0 9.8 4.7 2024.0837 FEB 242.5 122.7 47.5 12.5 9.7 4.9 2024.1670 MAR 237.2 124.1 50.1 12.2 9.2 5.1 2024.2503 APR 233.2 126.0 53.9 12.0 8.7 4.9 2024.3337 MAY 230.4 127.2 56.7 12.3 8.6 4.7 2024.4170 JUN 229.6 127.7 57.8 13.3 8.5 4.4 2024.5003 JUL 229.8 128.5 58.9 14.3 8.5 4.3 2024.5837 AUG 228.7 129.9 61.7 14.7 8.6 4.6 2024.6670 SEP 226.3 130.8 65.4 15.4 8.6 4.6 2024.7503 OCT 225.8 130.9 65.0 15.5 8.5 4.4 2024.8337 NOV 224.4 130.5 63.7 15.0 8.7 4.6 2024.9170 DEC 224.7 130.2 63.1 14.9 8.7 4.6 2025.0003 JAN 223.4 130.3 64.7 13.9 8.6 5.4 2025.0837 FEB 219.4 129.2 66.0 12.4 8.6 5.5 2025.1670 MAR 213.5 126.6 66.3 12.4 8.8 5.8 2025.2503 APR 209.6 123.9 64.3 12.9 9.2 5.9 2025.3337 MAY 204.9 121.6 61.4 13.2 9.4 6.1 2025.4170 JUN 198.4 119.5 59.0 14.1 9.8 6.4 2025.5003 JUL 193.4 116.8 57.9 14.8 10.1 6.6 2025.5837 AUG 188.9 114.0 55.4 15.5 9.9 6.4 2025.6670 SEP 184.7 112.2 53.7 15.9 10.0 6.3 2025.7503 OCT 181.8 111.4 54.3 16.4 10.3 6.4 2025.8337 NOV 177.0 110.1 54.7 16.3 10.3 6.2 2025.9170 DEC 172.9 107.5 52.4 15.7 10.4 6.0 2026.0003 JAN 169.3 105.2 50.6 14.7 10.4 5.9 2026.0837 FEB 165.2 103.3 49.3 13.8 10.5 5.9 2026.1670 MAR 160.6 100.9 45.6 13.3 11.0 6.4 2026.2503 APR 156.0 98.5 42.1 14.0 11.4 7.0 2026.3337 MAY 151.6 96.2 40.5 14.7 11.7 7.9 2026.4170 JUN 146.2 93.9 38.9 15.0 11.9 7.8 2026.5003 JUL 140.1 91.7 37.0 14.7 12.2 8.2 2026.5837 AUG 135.7 89.9 35.2 15.7 12.4 8.7 2026.6670 SEP 128.5 87.7 34.3 17.0 12.5 9.0 2026.7503 OCT 126.0 84.7 33.2 17.8 12.5 9.6 2026.8337 NOV 124.4 81.3 32.1 18.3 12.8 9.6 2026.9170 DEC 121.2 77.5 29.8 18.1 13.1 9.3 2027.0003 JAN 116.1 74.1 27.8 18.6 13.2 9.0 2027.0837 FEB 109.7 71.8 27.2 18.4 13.2 8.5 2027.1670 MAR 106.2 69.6 24.7 18.5 13.1 8.3 2027.2503 APR 108.1 67.9 21.2 19.0 13.1 8.3 2027.3337 MAY 109.4 66.4 18.7 19.3 12.8 8.0 2027.4170 JUN 110.7 65.1 17.2 19.7 12.5 7.0 2027.5003 JUL 108.8 62.6 15.1 20.2 12.1 6.0 2027.5837 AUG 107.4 60.2 13.2 20.7 11.8 5.9 2027.6670 SEP 105.1 58.3 11.8 21.1 11.6 5.8 2027.7503 OCT 101.2 56.0 10.0 21.4 11.7 5.8 2027.8337 NOV 97.3 54.2 8.8 21.1 11.4 5.7 2027.9170 DEC 95.1 52.6 7.5 20.3 11.1 5.7 2028.0003 JAN 95.5 51.5 7.1 19.4 10.9 5.9 2028.0837 FEB 95.8 50.7 7.0 18.7 10.9 6.1 2028.1670 MAR 93.4 49.5 7.3 18.5 11.1 5.8 2028.2503 APR 89.9 48.3 8.6 18.2 11.2 5.1 2028.3337 MAY 84.9 46.2 8.9 18.0 11.4 4.6 2028.4170 JUN 80.6 44.2 8.2 17.8 11.7 4.6 2028.5003 JUL 80.7 43.3 8.5 17.6 11.9 5.1 2028.5837 AUG 79.5 42.4 9.3 18.0 11.8 5.7 2028.6670 SEP 74.2 39.8 9.3 18.2 11.7 6.0 2028.7503 OCT 69.5 37.1 8.3 18.3 11.4 6.0 2028.8337 NOV 67.7 35.3 6.9 18.1 11.5 6.1 2028.9170 DEC 66.6 33.5 7.2 17.9 11.7 6.4 2029.0003 JAN 63.3 31.3 6.7 17.7 12.0 6.7 2029.0837 FEB 58.4 29.2 5.9 17.1 12.2 7.0 2029.1670 MAR 54.5 27.2 4.6 16.2 12.1 7.0 2029.2503 APR 52.5 25.3 3.5 16.3 11.8 6.7 2029.3337 MAY 50.4 23.7 3.2 16.3 11.5 6.5 2029.4170 JUN 48.1 22.5 3.0 16.2 11.2 6.1 2029.5003 JUL 45.8 21.6 2.8 16.3 11.2 5.6 2029.5837 AUG 43.4 20.7 2.2 16.7 11.4 5.5 2029.6670 SEP 40.7 19.8 1.3 17.2 11.4 5.9 2029.7503 OCT 38.1 19.0 0.4 17.1 11.3 6.3 2029.8337 NOV 35.3 18.4 0.3 16.9 11.2 6.4 2029.9170 DEC 33.9 17.4 0.4 16.6 10.9 6.4 2030.0003 JAN 32.2 16.0 0.2 15.5 10.4 6.3 2030.0837 FEB 30.6 14.9 0.0 13.9 9.9 6.1 2030.1670 MAR 29.9 13.8 0.0 12.7 9.4 5.8 2030.2503 APR 29.7 13.2 0.0 12.8 9.1 5.7 2030.3337 MAY 29.0 12.2 0.0 12.5 8.7 5.6 2030.4170 JUN 27.9 11.0 0.0 12.1 8.5 5.5 2030.5003 JUL 25.9 10.0 0.0 12.0 8.4 5.4 2030.5837 AUG 23.3 9.3 0.0 11.7 8.2 5.0 2030.6670 SEP 20.7 8.6 0.0 11.0 7.9 4.5 2030.7503 OCT 19.0 8.0 0.0 10.5 7.7 4.0 2030.8337 NOV 16.7 7.4 0.0 10.2 7.5 3.7 2030.9170 DEC 16.8 7.6 0.0 10.3 7.6 3.8 2031.0003 JAN 17.9 8.4 0.7 10.6 7.7 3.6 2031.0837 FEB 19.9 9.7 1.3 11.0 8.0 3.7 2031.1670 MAR 21.8 10.9 1.7 11.2 8.2 3.7 2031.2503 APR 24.6 12.1 2.3 11.4 8.3 3.5 2031.3337 MAY 27.6 13.4 2.5 11.6 8.5 3.3 2031.4170 JUN 32.3 15.1 3.2 11.8 8.7 3.3 2031.5003 JUL 36.0 17.0 4.4 12.0 8.8 3.3 2031.5837 AUG 39.9 18.9 5.0 12.4 9.1 3.3 2031.6670 SEP 45.5 21.2 5.6 12.7 9.5 3.3 2031.7503 OCT 52.6 23.6 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