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% 2020.3337 MAY 5.8 4.0 2.1 5.7 5.2 4.9 2020.4170 JUN 8.2 4.5 0.9 6.2 5.3 4.5 2020.5003 JUL 11.0 5.7 0.5 6.6 5.2 4.2 2020.5837 AUG 13.6 7.0 0.2 7.2 5.2 4.1 2020.6670 SEP 18.6 7.9 0.0 7.3 5.2 4.0 2020.7503 OCT 22.8 8.8 0.0 7.5 5.4 4.0 2020.8337 NOV 26.9 9.5 0.0 7.7 5.7 4.1 2020.9170 DEC 31.5 10.7 0.0 7.8 5.8 4.3 2021.0003 JAN 34.7 12.2 0.0 7.8 5.6 3.8 2021.0837 FEB 39.6 13.5 0.0 7.9 5.6 3.4 2021.1670 MAR 46.8 15.5 0.0 8.4 5.6 3.4 2021.2503 APR 55.0 18.1 0.0 9.0 5.6 3.1 2021.3337 MAY 63.2 20.4 0.0 10.1 5.8 2.9 2021.4170 JUN 72.0 22.5 0.0 10.9 6.0 2.9 2021.5003 JUL 79.7 25.7 0.0 11.0 6.1 2.8 2021.5837 AUG 85.5 29.6 0.0 11.0 6.2 2.8 2021.6670 SEP 91.3 33.9 0.0 10.5 6.2 2.8 2021.7503 OCT 99.6 38.3 0.0 9.9 6.1 2.9 2021.8337 NOV 109.9 42.2 0.0 9.3 6.1 3.1 2021.9170 DEC 121.2 46.1 0.0 8.8 6.1 3.2 2022.0003 JAN 131.6 50.7 0.0 8.8 6.4 3.6 2022.0837 FEB 139.9 54.6 0.0 10.0 6.7 4.2 2022.1670 MAR 149.0 58.2 0.0 10.4 7.2 4.8 2022.2503 APR 157.7 62.3 0.0 10.3 7.6 5.0 2022.3337 MAY 162.2 66.0 0.6 10.5 7.9 5.3 2022.4170 JUN 165.1 70.0 3.5 11.1 8.1 4.9 2022.5003 JUL 169.7 73.9 6.0 11.8 8.2 4.5 2022.5837 AUG 173.1 76.2 5.7 11.9 8.4 4.4 2022.6670 SEP 177.9 78.6 5.4 12.5 8.8 4.6 2022.7503 OCT 186.2 81.6 7.3 13.4 9.2 4.9 2022.8337 NOV 193.2 84.6 9.0 14.1 9.4 4.5 2022.9170 DEC 197.9 88.3 10.8 14.4 9.4 4.1 2023.0003 JAN 205.3 92.6 12.7 14.3 9.8 3.8 2023.0837 FEB 213.0 96.1 13.9 13.9 10.0 3.7 2023.1670 MAR 217.4 98.2 15.6 14.0 10.0 3.6 2023.2503 APR 220.5 99.4 15.2 14.4 10.0 3.5 2023.3337 MAY 223.9 100.3 14.5 15.2 9.9 3.3 2023.4170 JUN 227.0 102.0 14.2 15.4 9.9 3.3 2023.5003 JUL 229.9 104.2 15.1 15.0 10.1 3.7 2023.5837 AUG 233.4 106.6 18.3 14.8 10.2 4.3 2023.6670 SEP 236.7 109.0 20.8 14.3 10.2 4.6 2023.7503 OCT 235.7 110.0 22.0 13.7 10.0 4.6 2023.8337 NOV 234.6 111.2 24.6 13.7 10.0 4.8 2023.9170 DEC 236.4 112.3 27.3 13.5 10.1 4.9 2024.0003 JAN 236.9 112.6 29.9 12.8 9.8 4.7 2024.0837 FEB 233.6 113.7 33.7 12.5 9.7 4.8 2024.1670 MAR 228.6 115.5 38.7 12.3 9.2 5.0 2024.2503 APR 225.0 117.7 44.1 12.2 8.7 4.8 2024.3337 MAY 222.2 118.9 48.1 12.4 8.6 4.6 2024.4170 JUN 221.7 119.4 50.1 13.2 8.6 4.3 2024.5003 JUL 222.1 120.4 51.4 14.1 8.6 4.2 2024.5837 AUG 221.3 122.2 54.5 14.5 8.7 4.5 2024.6670 SEP 219.2 123.5 58.6 15.2 8.6 4.5 2024.7503 OCT 218.9 123.9 59.6 15.3 8.5 4.3 2024.8337 NOV 218.3 123.8 58.6 14.8 8.7 4.5 2024.9170 DEC 219.0 124.0 58.3 14.7 8.8 4.5 2025.0003 JAN 218.1 124.5 60.3 13.9 8.7 5.5 2025.0837 FEB 214.4 123.7 61.7 12.5 8.7 5.7 2025.1670 MAR 208.3 121.0 61.2 12.5 9.0 6.0 2025.2503 APR 204.4 118.4 59.2 13.0 9.4 6.1 2025.3337 MAY 199.7 116.1 56.2 13.6 9.6 6.4 2025.4170 JUN 193.2 113.9 53.7 14.7 10.0 6.6 2025.5003 JUL 188.3 111.3 52.8 15.6 10.4 6.9 2025.5837 AUG 183.6 108.4 51.4 16.4 10.2 6.8 2025.6670 SEP 179.5 106.7 49.7 16.8 10.3 6.6 2025.7503 OCT 176.9 106.2 50.4 17.4 10.6 6.7 2025.8337 NOV 172.3 105.1 50.9 17.3 10.6 6.5 2025.9170 DEC 168.1 102.3 48.4 16.7 10.6 6.3 2026.0003 JAN 164.4 100.0 47.2 15.7 10.6 6.2 2026.0837 FEB 160.1 98.2 45.9 14.4 10.7 6.1 2026.1670 MAR 155.8 95.8 42.2 13.9 11.2 6.6 2026.2503 APR 151.2 93.3 38.8 14.2 11.6 7.2 2026.3337 MAY 146.8 91.1 37.3 14.9 11.9 8.1 2026.4170 JUN 141.3 88.7 35.6 15.0 12.0 7.8 2026.5003 JUL 135.4 86.7 33.7 14.7 12.2 8.0 2026.5837 AUG 130.2 85.1 32.2 15.7 12.4 8.6 2026.6670 SEP 124.3 83.1 31.3 17.1 12.5 8.9 2026.7503 OCT 121.1 80.2 30.1 17.9 12.6 9.8 2026.8337 NOV 119.2 76.5 28.8 18.4 12.9 9.4 2026.9170 DEC 116.0 72.4 26.4 18.2 13.1 9.1 2027.0003 JAN 110.1 68.8 24.1 18.7 13.3 8.8 2027.0837 FEB 104.0 66.4 23.2 18.6 13.4 8.4 2027.1670 MAR 103.0 64.3 20.7 18.7 13.3 8.2 2027.2503 APR 105.0 62.8 17.1 19.2 13.2 8.2 2027.3337 MAY 106.5 61.4 14.4 19.5 13.0 8.0 2027.4170 JUN 107.4 60.2 12.9 20.0 12.7 7.0 2027.5003 JUL 105.3 57.8 10.8 20.5 12.3 6.1 2027.5837 AUG 104.1 55.5 9.0 20.9 12.0 5.9 2027.6670 SEP 102.1 53.7 7.7 21.2 11.8 5.8 2027.7503 OCT 97.3 51.3 6.0 21.5 11.8 5.7 2027.8337 NOV 94.1 49.6 4.8 21.2 11.5 5.6 2027.9170 DEC 92.5 48.2 3.7 20.5 11.2 5.5 2028.0003 JAN 93.2 47.5 3.4 19.5 11.0 5.7 2028.0837 FEB 93.6 46.8 3.4 18.8 10.9 6.0 2028.1670 MAR 91.3 45.8 3.6 18.5 11.2 6.2 2028.2503 APR 88.0 44.7 4.9 18.2 11.2 5.5 2028.3337 MAY 83.1 42.7 5.5 18.0 11.5 4.9 2028.4170 JUN 78.4 40.6 5.1 17.8 11.7 5.0 2028.5003 JUL 78.4 39.9 5.5 17.6 11.9 5.5 2028.5837 AUG 77.3 39.1 6.7 18.0 11.8 6.0 2028.6670 SEP 72.0 36.5 6.6 18.2 11.7 6.3 2028.7503 OCT 67.4 33.8 4.9 18.3 11.5 6.3 2028.8337 NOV 65.8 32.0 3.6 18.1 11.5 6.4 2028.9170 DEC 64.8 30.3 4.1 18.0 11.7 6.6 2029.0003 JAN 61.5 28.2 4.2 17.7 12.0 7.0 2029.0837 FEB 56.6 26.1 3.5 17.1 12.2 7.2 2029.1670 MAR 52.2 24.3 2.3 16.3 12.2 7.1 2029.2503 APR 50.2 22.3 1.1 16.3 11.8 6.9 2029.3337 MAY 48.1 20.8 1.1 16.3 11.5 6.7 2029.4170 JUN 45.9 19.8 1.0 16.3 11.3 6.4 2029.5003 JUL 43.7 19.1 0.9 16.3 11.2 5.8 2029.5837 AUG 40.8 18.2 0.6 16.7 11.3 5.7 2029.6670 SEP 38.2 17.5 0.0 17.1 11.4 6.1 2029.7503 OCT 35.1 16.8 0.0 17.1 11.3 6.5 2029.8337 NOV 33.7 16.4 0.0 16.9 11.2 6.6 2029.9170 DEC 32.3 15.5 0.0 16.6 10.9 6.5 2030.0003 JAN 30.8 14.3 0.0 15.5 10.5 6.4 2030.0837 FEB 29.0 13.3 0.0 13.9 9.9 6.3 2030.1670 MAR 28.2 12.4 0.0 12.7 9.5 6.0 2030.2503 APR 28.3 12.0 0.0 12.8 9.1 5.9 2030.3337 MAY 27.6 11.1 0.0 12.5 8.7 5.8 2030.4170 JUN 26.4 9.9 0.0 12.2 8.5 5.7 2030.5003 JUL 24.6 9.0 0.0 12.0 8.4 5.6 2030.5837 AUG 22.1 8.3 0.0 11.7 8.2 5.2 2030.6670 SEP 19.5 7.7 0.0 11.0 7.9 4.6 2030.7503 OCT 17.9 7.2 0.0 10.5 7.7 4.1 2030.8337 NOV 15.8 6.7 0.0 10.2 7.5 3.8 2030.9170 DEC 16.0 6.9 0.0 10.3 7.5 3.9 2031.0003 JAN 17.2 7.8 0.7 10.6 7.7 3.7 2031.0837 FEB 19.2 9.1 1.3 11.0 8.0 3.8 2031.1670 MAR 21.2 10.4 1.7 11.2 8.2 3.8 2031.2503 APR 24.0 11.6 2.3 11.4 8.3 3.5 2031.3337 MAY 27.1 13.0 2.5 11.6 8.5 3.4 2031.4170 JUN 31.9 14.8 3.2 11.8 8.6 3.4 2031.5003 JUL 35.7 16.7 4.4 12.0 8.8 3.3 2031.5837 AUG 39.6 18.8 5.0 12.4 9.1 3.3 2031.6670 SEP 45.3 21.0 5.6 12.7 9.4 3.4 2031.7503 OCT 52.5 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