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% 2020.7503 OCT 12.9 11.2 9.1 6.7 6.0 5.7 2020.8337 NOV 16.4 12.0 8.0 7.6 6.3 5.6 2020.9170 DEC 19.2 13.2 6.5 8.0 6.4 5.5 2021.0003 JAN 21.8 14.8 4.9 8.1 6.5 5.2 2021.0837 FEB 27.4 16.2 3.6 8.8 6.5 4.9 2021.1670 MAR 32.9 17.9 1.6 9.4 6.6 4.4 2021.2503 APR 38.7 20.2 0.3 10.2 6.7 4.0 2021.3337 MAY 46.4 22.4 0.8 11.3 6.9 3.9 2021.4170 JUN 55.7 24.6 0.9 12.2 7.2 4.0 2021.5003 JUL 65.1 28.0 1.6 12.5 7.4 4.0 2021.5837 AUG 74.5 32.6 2.4 12.5 7.6 4.1 2021.6670 SEP 83.2 37.2 4.2 12.0 7.6 4.0 2021.7503 OCT 92.2 42.1 7.8 11.3 7.5 4.2 2021.8337 NOV 103.0 46.6 11.5 10.7 7.4 4.4 2021.9170 DEC 114.3 50.8 12.7 10.9 7.5 4.4 2022.0003 JAN 124.9 55.6 14.1 10.9 7.6 4.7 2022.0837 FEB 135.1 60.3 15.9 10.8 7.9 5.3 2022.1670 MAR 146.0 64.7 17.4 11.0 8.2 5.7 2022.2503 APR 157.2 69.4 20.1 10.9 8.5 6.3 2022.3337 MAY 164.8 74.1 22.8 11.0 8.7 6.6 2022.4170 JUN 170.2 79.1 26.8 11.6 9.0 6.2 2022.5003 JUL 177.0 83.6 29.3 12.4 9.2 5.9 2022.5837 AUG 182.6 86.4 28.8 12.6 9.4 5.8 2022.6670 SEP 188.2 88.9 28.8 13.0 9.7 5.9 2022.7503 OCT 196.5 92.1 31.6 13.9 10.1 6.1 2022.8337 NOV 204.1 95.7 34.8 14.6 10.3 5.8 2022.9170 DEC 209.6 100.3 37.8 15.1 10.5 5.6 2023.0003 JAN 217.2 105.0 41.8 15.5 10.8 5.3 2023.0837 FEB 225.3 109.0 45.5 16.0 10.9 4.9 2023.1670 MAR 230.7 112.4 47.2 16.3 11.0 4.9 2023.2503 APR 235.4 115.6 49.5 16.9 11.1 5.1 2023.3337 MAY 240.4 118.4 50.4 17.9 11.1 5.1 2023.4170 JUN 244.1 120.8 50.8 18.1 11.2 5.2 2023.5003 JUL 247.2 123.4 51.3 17.5 11.2 5.6 2023.5837 AUG 250.1 126.1 54.0 17.1 11.4 6.0 2023.6670 SEP 253.0 129.1 56.9 16.6 11.3 6.3 2023.7503 OCT 253.5 131.3 60.2 16.1 11.1 6.4 2023.8337 NOV 253.5 133.4 64.0 16.1 11.1 6.5 2023.9170 DEC 255.4 134.8 66.4 15.9 11.2 6.7 2024.0003 JAN 255.3 134.8 66.5 15.2 11.1 6.6 2024.0837 FEB 250.9 134.8 66.3 14.5 11.0 6.9 2024.1670 MAR 246.0 135.5 66.8 13.9 10.6 7.0 2024.2503 APR 241.8 137.0 69.5 13.4 10.1 6.4 2024.3337 MAY 238.9 138.2 70.7 13.5 10.0 6.1 2024.4170 JUN 237.5 138.5 69.5 14.4 10.0 5.8 2024.5003 JUL 236.1 138.9 69.2 15.3 10.1 5.6 2024.5837 AUG 235.0 139.9 70.9 15.8 10.2 5.7 2024.6670 SEP 233.9 140.7 73.8 16.6 10.2 5.6 2024.7503 OCT 233.5 140.5 74.5 16.7 10.2 5.6 2024.8337 NOV 231.4 139.6 73.1 16.2 10.4 6.3 2024.9170 DEC 229.9 139.0 71.9 15.9 10.3 6.9 2025.0003 JAN 228.5 138.6 72.8 14.9 10.1 6.9 2025.0837 FEB 226.1 137.7 73.6 15.0 10.1 6.9 2025.1670 MAR 222.5 135.7 71.9 15.0 10.4 7.5 2025.2503 APR 219.1 133.6 70.8 15.7 10.7 7.5 2025.3337 MAY 214.8 131.9 69.7 15.9 10.9 7.5 2025.4170 JUN 208.8 130.3 68.3 16.3 11.2 7.4 2025.5003 JUL 204.1 127.9 66.7 16.7 11.4 7.6 2025.5837 AUG 200.0 125.7 64.3 15.9 11.2 7.4 2025.6670 SEP 196.6 124.3 63.0 15.7 11.3 7.3 2025.7503 OCT 195.9 123.3 63.5 16.7 11.6 7.4 2025.8337 NOV 191.5 121.7 63.0 16.7 11.6 7.3 2025.9170 DEC 188.9 119.3 58.6 16.6 11.7 7.1 2026.0003 JAN 187.4 117.0 57.0 16.7 11.9 7.1 2026.0837 FEB 182.9 114.8 57.3 16.8 12.1 7.0 2026.1670 MAR 177.0 112.4 53.5 16.0 12.5 7.5 2026.2503 APR 170.8 109.8 49.5 16.1 12.8 8.0 2026.3337 MAY 165.0 107.5 47.4 16.8 13.1 8.9 2026.4170 JUN 160.3 105.2 46.2 17.2 13.4 9.1 2026.5003 JUL 157.3 103.1 44.7 17.1 13.7 9.6 2026.5837 AUG 152.8 101.1 43.2 17.2 13.8 9.7 2026.6670 SEP 144.5 98.4 42.5 18.4 13.8 9.7 2026.7503 OCT 136.9 95.2 42.3 19.0 13.7 9.7 2026.8337 NOV 135.0 91.8 41.9 19.2 13.8 10.0 2026.9170 DEC 132.8 88.3 39.7 19.2 14.0 10.0 2027.0003 JAN 128.3 85.4 38.0 19.5 14.1 10.3 2027.0837 FEB 124.1 83.3 39.1 19.2 13.9 9.8 2027.1670 MAR 119.8 81.1 39.0 19.2 13.8 9.5 2027.2503 APR 115.4 79.2 37.9 19.6 13.6 9.4 2027.3337 MAY 115.6 77.3 36.2 19.8 13.3 9.0 2027.4170 JUN 116.7 75.3 34.0 20.1 13.0 7.9 2027.5003 JUL 115.1 72.4 31.4 20.5 12.5 6.9 2027.5837 AUG 113.6 69.7 27.7 21.1 12.3 7.0 2027.6670 SEP 111.2 67.7 24.8 21.7 12.3 7.1 2027.7503 OCT 107.4 65.5 22.7 22.0 12.3 7.2 2027.8337 NOV 103.4 63.5 19.9 21.8 12.1 7.2 2027.9170 DEC 100.3 61.5 17.6 21.2 11.9 7.0 2028.0003 JAN 99.5 60.1 16.3 20.4 11.8 6.4 2028.0837 FEB 98.5 58.8 15.3 19.8 11.8 6.1 2028.1670 MAR 95.3 57.3 14.5 19.6 12.1 5.8 2028.2503 APR 91.4 55.8 14.8 19.3 12.2 5.2 2028.3337 MAY 87.2 53.7 14.8 19.2 12.4 4.8 2028.4170 JUN 87.2 51.8 13.9 19.0 12.7 4.9 2028.5003 JUL 87.8 50.9 13.7 18.5 12.8 5.4 2028.5837 AUG 85.3 49.7 13.5 18.6 12.6 5.8 2028.6670 SEP 80.6 47.0 12.7 18.8 12.5 6.2 2028.7503 OCT 75.8 44.2 12.0 18.9 12.3 6.2 2028.8337 NOV 71.1 42.0 11.6 18.7 12.3 6.4 2028.9170 DEC 68.3 39.9 10.5 18.5 12.5 6.7 2029.0003 JAN 65.6 37.3 9.1 18.3 12.7 7.2 2029.0837 FEB 62.6 35.0 8.4 17.7 13.0 7.5 2029.1670 MAR 60.3 32.9 6.9 16.9 13.0 7.7 2029.2503 APR 58.4 30.8 5.3 17.0 12.8 7.4 2029.3337 MAY 56.6 28.9 5.0 17.0 12.6 7.1 2029.4170 JUN 54.8 27.5 5.0 17.1 12.4 7.0 2029.5003 JUL 53.1 26.4 4.8 17.2 12.4 6.5 2029.5837 AUG 51.3 25.3 4.7 17.6 12.5 6.6 2029.6670 SEP 49.0 24.2 4.0 18.0 12.5 6.6 2029.7503 OCT 46.1 23.0 3.1 17.9 12.3 6.5 2029.8337 NOV 42.4 22.1 2.7 17.6 12.1 6.5 2029.9170 DEC 37.8 20.8 2.7 17.3 11.8 6.3 2030.0003 JAN 34.7 19.1 2.1 16.2 11.3 6.3 2030.0837 FEB 33.1 17.6 1.5 14.6 10.7 6.3 2030.1670 MAR 32.2 16.3 1.2 13.3 10.2 6.3 2030.2503 APR 32.0 15.4 1.2 13.3 9.8 6.1 2030.3337 MAY 31.2 14.3 1.0 12.9 9.3 5.9 2030.4170 JUN 30.2 13.1 0.8 12.6 9.0 5.8 2030.5003 JUL 27.8 12.0 0.6 12.4 8.9 5.7 2030.5837 AUG 25.1 11.2 0.3 12.1 8.7 5.3 2030.6670 SEP 23.3 10.5 0.1 11.4 8.5 4.8 2030.7503 OCT 21.6 9.8 0.0 10.9 8.3 4.4 2030.8337 NOV 19.1 9.2 0.1 10.7 8.1 4.1 2030.9170 DEC 19.1 9.2 0.0 10.8 8.2 4.1 2031.0003 JAN 20.0 9.9 0.8 11.0 8.3 4.0 2031.0837 FEB 21.8 11.0 1.4 11.4 8.5 4.0 2031.1670 MAR 23.4 12.1 1.7 11.5 8.6 4.0 2031.2503 APR 26.0 13.1 2.3 11.7 8.7 3.7 2031.3337 MAY 28.8 14.2 2.5 11.9 8.8 3.5 2031.4170 JUN 33.4 15.8 3.2 12.0 8.9 3.5 2031.5003 JUL 36.8 17.5 4.4 12.1 9.1 3.4 2031.5837 AUG 40.5 19.4 5.0 12.5 9.3 3.4 2031.6670 SEP 45.9 21.5 5.6 12.8 9.6 3.4 2031.7503 OCT 52.8 23.7 6.1 13.3 10.0 3.8 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