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% 2020.0003 JAN 3.8 2.5 1.9 5.6 5.4 5.1 2020.0837 FEB 6.7 3.6 2.0 5.8 5.5 4.9 2020.1670 MAR 8.9 4.7 2.0 5.8 5.5 4.9 2020.2503 APR 11.5 5.6 2.2 5.9 5.4 4.8 2020.3337 MAY 14.6 6.4 2.3 6.0 5.5 4.8 2020.4170 JUN 18.6 7.5 2.1 6.1 5.5 4.6 2020.5003 JUL 22.1 9.0 1.6 6.4 5.5 4.4 2020.5837 AUG 25.4 10.6 1.2 7.0 5.4 4.2 2020.6670 SEP 30.0 12.1 1.4 7.1 5.4 4.0 2020.7503 OCT 35.8 13.7 1.9 7.2 5.6 4.0 2020.8337 NOV 44.3 15.6 1.1 7.4 5.8 4.0 2020.9170 DEC 51.3 17.7 0.0 7.5 5.9 4.3 2021.0003 JAN 56.2 19.7 0.0 7.4 5.8 4.0 2021.0837 FEB 63.7 21.8 0.0 7.3 5.7 3.6 2021.1670 MAR 72.4 24.5 0.0 7.3 5.6 3.5 2021.2503 APR 80.5 27.7 0.0 7.8 5.6 3.1 2021.3337 MAY 90.5 30.9 0.0 8.8 5.7 2.8 2021.4170 JUN 102.4 34.3 0.0 9.6 5.9 2.8 2021.5003 JUL 111.2 37.9 0.0 9.8 6.1 2.8 2021.5837 AUG 117.6 41.9 0.0 9.7 6.2 2.8 2021.6670 SEP 124.0 46.2 0.0 9.2 6.2 2.8 2021.7503 OCT 130.9 50.8 0.0 8.6 6.2 3.0 2021.8337 NOV 138.1 54.7 0.6 8.0 6.1 3.2 2021.9170 DEC 145.8 58.8 2.5 8.2 6.2 3.3 2022.0003 JAN 153.9 63.4 4.0 9.1 6.4 3.7 2022.0837 FEB 162.8 67.3 5.5 10.3 6.8 4.4 2022.1670 MAR 172.9 71.3 6.4 10.7 7.3 5.0 2022.2503 APR 182.1 75.7 8.9 10.6 7.7 5.2 2022.3337 MAY 187.2 79.3 10.0 10.8 8.0 5.5 2022.4170 JUN 188.3 82.9 11.4 11.4 8.2 5.2 2022.5003 JUL 191.2 86.5 13.2 12.0 8.4 4.8 2022.5837 AUG 195.7 89.2 14.3 12.2 8.5 4.7 2022.6670 SEP 201.3 92.1 16.5 12.7 8.9 4.8 2022.7503 OCT 210.0 95.4 16.6 13.6 9.3 5.0 2022.8337 NOV 215.2 98.0 15.4 14.3 9.5 4.7 2022.9170 DEC 216.7 100.3 15.4 14.6 9.5 4.3 2023.0003 JAN 221.6 103.3 14.8 14.5 9.8 4.0 2023.0837 FEB 228.0 106.1 15.1 14.1 10.1 3.8 2023.1670 MAR 232.0 107.5 16.5 13.8 10.1 3.7 2023.2503 APR 235.0 108.3 15.0 14.2 10.1 3.7 2023.3337 MAY 238.4 108.7 12.6 15.0 10.0 3.5 2023.4170 JUN 241.2 109.9 11.0 15.2 9.9 3.4 2023.5003 JUL 243.2 111.2 11.4 14.9 10.1 3.9 2023.5837 AUG 244.7 112.4 14.3 14.7 10.4 4.5 2023.6670 SEP 246.5 113.9 16.6 14.3 10.3 4.9 2023.7503 OCT 245.7 114.3 16.9 13.7 10.1 4.9 2023.8337 NOV 244.5 114.9 18.8 13.6 10.1 5.0 2023.9170 DEC 245.9 115.7 21.3 13.7 10.2 5.1 2024.0003 JAN 245.7 115.7 23.7 13.3 10.0 5.0 2024.0837 FEB 241.4 116.3 27.5 13.1 9.9 5.3 2024.1670 MAR 236.6 117.4 32.3 12.8 9.5 5.5 2024.2503 APR 232.1 119.0 37.4 12.7 9.1 5.4 2024.3337 MAY 229.0 119.9 41.2 13.0 9.0 5.3 2024.4170 JUN 227.4 120.1 43.7 14.1 9.0 5.1 2024.5003 JUL 226.8 120.6 46.8 15.1 9.0 5.1 2024.5837 AUG 225.5 121.9 50.4 15.6 9.2 5.4 2024.6670 SEP 223.8 122.9 54.3 16.4 9.2 5.5 2024.7503 OCT 223.4 123.4 56.4 16.6 9.1 5.4 2024.8337 NOV 222.0 123.6 56.5 16.1 9.3 5.6 2024.9170 DEC 222.2 123.7 57.5 16.0 9.4 5.6 2025.0003 JAN 220.9 124.0 60.6 15.2 9.3 5.8 2025.0837 FEB 217.1 122.9 62.9 13.6 9.3 5.6 2025.1670 MAR 211.4 119.8 64.2 13.6 9.6 5.5 2025.2503 APR 207.5 116.9 65.0 14.0 9.9 5.6 2025.3337 MAY 203.3 114.6 62.1 14.3 10.1 5.8 2025.4170 JUN 197.2 112.4 59.1 15.1 10.4 6.5 2025.5003 JUL 192.1 109.7 57.1 15.6 10.7 6.9 2025.5837 AUG 186.0 106.6 54.2 16.2 10.5 6.6 2025.6670 SEP 180.6 104.5 52.0 16.5 10.5 6.8 2025.7503 OCT 177.3 103.7 52.0 16.9 10.7 7.1 2025.8337 NOV 172.3 102.3 51.9 16.8 10.7 7.0 2025.9170 DEC 166.7 99.3 49.0 16.2 10.7 6.8 2026.0003 JAN 162.4 96.5 47.2 15.2 10.7 6.7 2026.0837 FEB 158.0 94.7 46.3 13.9 10.8 6.5 2026.1670 MAR 154.4 92.8 43.0 13.4 11.3 7.0 2026.2503 APR 151.3 90.9 40.0 14.3 11.6 7.5 2026.3337 MAY 147.9 89.0 38.4 15.0 11.9 8.4 2026.4170 JUN 142.4 86.8 36.8 15.2 12.1 8.1 2026.5003 JUL 135.6 84.7 34.6 14.9 12.3 8.4 2026.5837 AUG 131.1 83.1 32.8 15.8 12.4 8.9 2026.6670 SEP 127.3 81.3 31.9 17.1 12.5 9.2 2026.7503 OCT 123.4 78.4 31.3 17.9 12.6 9.8 2026.8337 NOV 120.5 74.7 31.2 18.4 12.9 9.2 2026.9170 DEC 116.0 70.6 29.1 18.2 13.2 9.0 2027.0003 JAN 111.6 67.0 27.2 18.3 13.4 8.8 2027.0837 FEB 110.5 64.7 27.2 18.2 13.5 8.4 2027.1670 MAR 112.4 62.6 26.1 18.3 13.4 8.2 2027.2503 APR 113.8 60.8 23.6 18.8 13.3 8.2 2027.3337 MAY 114.7 59.3 20.2 19.1 13.0 7.8 2027.4170 JUN 114.9 58.0 18.1 19.5 12.7 6.8 2027.5003 JUL 112.7 55.9 16.2 19.9 12.3 5.8 2027.5837 AUG 111.4 54.0 14.6 20.2 11.9 5.5 2027.6670 SEP 109.1 52.1 13.1 20.5 11.7 5.4 2027.7503 OCT 104.5 49.7 11.5 20.8 11.7 5.4 2027.8337 NOV 100.4 47.8 10.0 20.4 11.4 5.2 2027.9170 DEC 98.4 46.2 8.2 19.7 11.1 5.2 2028.0003 JAN 98.5 45.2 7.0 18.8 10.9 5.3 2028.0837 FEB 98.4 44.4 6.2 18.1 10.9 5.7 2028.1670 MAR 95.7 43.2 5.8 18.0 11.2 5.9 2028.2503 APR 91.9 42.0 6.2 17.7 11.3 5.2 2028.3337 MAY 86.9 40.1 6.6 17.6 11.6 4.8 2028.4170 JUN 81.9 38.3 6.0 17.5 11.9 4.8 2028.5003 JUL 80.3 37.4 6.2 17.9 12.1 5.4 2028.5837 AUG 79.1 36.4 6.8 18.3 12.0 5.9 2028.6670 SEP 75.4 34.1 7.2 18.6 11.9 6.3 2028.7503 OCT 71.1 31.9 6.8 18.7 11.8 6.3 2028.8337 NOV 69.6 30.7 6.3 18.5 11.8 6.6 2028.9170 DEC 68.8 29.7 6.5 18.3 12.1 6.8 2029.0003 JAN 65.6 28.2 6.2 18.1 12.4 7.2 2029.0837 FEB 60.8 26.6 5.0 17.5 12.6 7.4 2029.1670 MAR 56.4 24.9 3.6 16.6 12.6 7.4 2029.2503 APR 53.4 23.2 2.2 16.7 12.3 7.2 2029.3337 MAY 50.2 21.7 1.7 16.8 12.0 7.0 2029.4170 JUN 47.8 20.7 2.0 16.8 11.7 6.6 2029.5003 JUL 46.2 19.9 2.3 16.9 11.7 6.1 2029.5837 AUG 42.9 18.6 1.8 17.2 11.9 6.1 2029.6670 SEP 38.0 17.5 0.4 17.6 11.9 6.4 2029.7503 OCT 35.2 16.5 0.0 17.5 11.8 6.5 2029.8337 NOV 34.4 15.8 0.0 17.3 11.7 6.5 2029.9170 DEC 32.4 14.6 0.0 17.0 11.4 6.3 2030.0003 JAN 29.6 13.3 0.0 15.9 10.9 6.3 2030.0837 FEB 27.3 12.3 0.0 14.3 10.3 6.2 2030.1670 MAR 25.8 11.5 0.0 13.0 9.8 6.2 2030.2503 APR 25.7 11.0 0.0 13.1 9.4 6.1 2030.3337 MAY 25.0 10.1 0.0 12.8 9.0 6.0 2030.4170 JUN 23.8 9.0 0.0 12.4 8.8 5.8 2030.5003 JUL 22.1 8.2 0.0 12.2 8.6 5.7 2030.5837 AUG 19.8 7.6 0.0 11.9 8.4 5.3 2030.6670 SEP 17.8 7.1 0.0 11.2 8.1 4.7 2030.7503 OCT 16.5 6.7 0.0 10.7 7.9 4.2 2030.8337 NOV 14.4 6.3 0.0 10.5 7.7 3.9 2030.9170 DEC 14.7 6.6 0.0 10.5 7.7 3.9 2031.0003 JAN 16.0 7.5 0.7 10.8 7.9 3.8 2031.0837 FEB 18.2 8.8 1.3 11.1 8.1 3.9 2031.1670 MAR 20.3 10.2 1.7 11.3 8.3 3.8 2031.2503 APR 23.2 11.4 2.3 11.6 8.4 3.6 2031.3337 MAY 26.4 12.8 2.5 11.7 8.6 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 9.2 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