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% 2022.1670 MAR 75.2 68.8 62.8 9.9 9.1 8.6 2022.2503 APR 88.0 73.0 62.1 11.1 9.5 8.8 2022.3337 MAY 96.7 77.7 62.6 12.0 9.8 8.7 2022.4170 JUN 107.8 82.4 62.5 12.3 10.1 8.3 2022.5003 JUL 118.3 86.5 60.9 12.0 10.3 7.9 2022.5837 AUG 126.6 89.3 62.1 12.3 10.3 7.6 2022.6670 SEP 133.9 92.0 61.2 12.6 10.5 7.5 2022.7503 OCT 143.8 94.9 57.5 12.6 10.7 7.4 2022.8337 NOV 155.6 97.8 52.8 12.8 10.8 7.0 2022.9170 DEC 165.6 101.1 47.7 13.0 10.9 6.5 2023.0003 JAN 171.8 104.4 43.6 13.8 11.1 6.0 2023.0837 FEB 175.4 107.4 41.9 14.4 11.2 5.6 2023.1670 MAR 179.6 110.5 41.4 14.7 11.3 5.6 2023.2503 APR 186.6 113.4 42.9 15.2 11.3 5.6 2023.3337 MAY 192.3 116.0 42.8 16.1 11.2 5.4 2023.4170 JUN 194.0 118.2 41.6 16.2 11.1 5.3 2023.5003 JUL 192.3 120.1 41.9 15.9 11.2 5.6 2023.5837 AUG 190.1 121.6 41.3 15.7 11.4 6.2 2023.6670 SEP 192.2 123.5 42.6 15.5 11.4 6.6 2023.7503 OCT 196.0 125.2 45.7 15.1 11.4 6.9 2023.8337 NOV 199.1 126.9 48.5 15.2 11.4 7.1 2023.9170 DEC 200.9 128.1 50.2 15.4 11.5 7.2 2024.0003 JAN 201.5 127.8 49.8 15.2 11.4 7.2 2024.0837 FEB 195.1 127.5 51.0 15.3 11.4 7.7 2024.1670 MAR 189.8 127.8 53.0 15.1 11.2 8.0 2024.2503 APR 189.9 129.1 54.2 14.5 10.7 7.4 2024.3337 MAY 193.7 130.4 53.8 14.1 10.6 7.6 2024.4170 JUN 197.0 130.9 52.7 14.7 10.7 7.8 2024.5003 JUL 198.8 131.2 50.7 15.7 10.8 8.0 2024.5837 AUG 199.8 131.9 48.2 16.3 11.0 8.0 2024.6670 SEP 200.0 132.7 47.0 17.3 11.2 7.8 2024.7503 OCT 196.6 132.8 44.8 17.5 11.2 7.4 2024.8337 NOV 189.8 132.2 43.1 17.0 11.4 7.6 2024.9170 DEC 186.4 131.5 42.1 17.0 11.4 7.5 2025.0003 JAN 184.0 130.9 42.7 16.5 11.5 7.2 2025.0837 FEB 180.9 129.5 42.3 16.6 11.5 7.1 2025.1670 MAR 180.8 127.5 41.5 16.6 11.8 7.2 2025.2503 APR 180.7 125.6 41.3 16.9 12.2 7.5 2025.3337 MAY 179.4 124.3 41.7 17.2 12.5 7.9 2025.4170 JUN 177.1 123.2 43.2 17.8 12.8 8.6 2025.5003 JUL 176.3 121.1 45.3 18.1 13.0 8.8 2025.5837 AUG 179.0 119.1 47.2 18.8 12.9 8.7 2025.6670 SEP 182.9 117.7 49.5 19.2 13.0 8.5 2025.7503 OCT 183.6 116.6 50.8 19.7 13.3 8.5 2025.8337 NOV 180.3 115.1 52.3 19.6 13.3 8.4 2025.9170 DEC 177.4 112.8 50.8 19.0 13.4 8.2 2026.0003 JAN 175.8 110.3 49.8 18.1 13.4 8.2 2026.0837 FEB 172.0 108.2 49.3 17.2 13.5 8.0 2026.1670 MAR 167.4 106.6 46.7 17.6 13.8 8.4 2026.2503 APR 162.2 105.0 44.5 18.4 14.0 8.8 2026.3337 MAY 157.1 103.3 43.9 19.0 14.3 9.7 2026.4170 JUN 153.4 101.5 43.5 19.2 14.5 10.3 2026.5003 JUL 151.0 99.4 42.4 18.7 14.6 10.5 2026.5837 AUG 145.9 97.0 40.2 19.0 14.7 10.7 2026.6670 SEP 137.5 94.2 39.1 20.2 14.7 11.0 2026.7503 OCT 130.1 91.3 39.0 20.8 14.7 11.3 2026.8337 NOV 127.0 88.5 39.1 20.9 14.8 11.7 2026.9170 DEC 125.4 85.6 38.0 20.6 15.0 11.1 2027.0003 JAN 122.7 83.2 37.0 20.2 15.1 10.8 2027.0837 FEB 120.2 81.5 38.4 19.8 14.9 10.6 2027.1670 MAR 117.9 79.6 38.2 19.6 14.7 10.0 2027.2503 APR 116.5 77.6 37.5 19.8 14.4 9.7 2027.3337 MAY 117.8 75.6 34.7 19.9 14.1 9.2 2027.4170 JUN 118.2 73.5 31.9 20.2 13.7 8.0 2027.5003 JUL 116.8 70.8 29.3 20.4 13.2 6.8 2027.5837 AUG 115.1 68.2 26.2 20.5 12.8 6.5 2027.6670 SEP 112.6 66.2 23.9 20.8 12.6 6.2 2027.7503 OCT 109.1 64.0 22.3 20.9 12.5 6.1 2027.8337 NOV 105.2 61.9 20.9 20.7 12.3 6.0 2027.9170 DEC 102.1 59.5 18.7 20.1 12.2 6.2 2028.0003 JAN 100.7 57.7 16.8 19.4 12.1 6.6 2028.0837 FEB 99.0 56.2 15.2 18.8 12.1 7.1 2028.1670 MAR 95.8 54.7 13.7 18.7 12.3 7.1 2028.2503 APR 91.8 53.0 13.5 18.5 12.4 6.4 2028.3337 MAY 86.8 50.8 13.7 18.4 12.6 5.9 2028.4170 JUN 84.5 48.9 13.1 18.1 12.8 5.9 2028.5003 JUL 84.9 47.8 12.9 18.3 12.9 6.3 2028.5837 AUG 82.3 46.7 12.4 18.7 12.9 6.8 2028.6670 SEP 77.7 44.5 11.9 19.0 12.8 7.2 2028.7503 OCT 73.8 42.2 11.1 19.1 12.6 7.3 2028.8337 NOV 70.1 40.4 11.0 18.9 12.6 7.4 2028.9170 DEC 68.7 38.8 10.3 18.7 12.7 7.5 2029.0003 JAN 66.4 36.8 9.4 18.3 12.9 7.7 2029.0837 FEB 63.8 34.8 8.7 17.8 13.1 7.9 2029.1670 MAR 62.0 32.8 7.5 17.0 13.1 7.9 2029.2503 APR 60.3 30.9 6.1 17.3 12.9 7.3 2029.3337 MAY 58.5 29.1 5.9 17.4 12.8 7.0 2029.4170 JUN 56.6 27.6 5.9 17.5 12.7 6.8 2029.5003 JUL 54.8 26.4 5.7 17.5 12.7 6.6 2029.5837 AUG 52.5 25.2 5.6 17.7 12.8 6.6 2029.6670 SEP 50.0 23.8 5.3 18.1 12.8 6.4 2029.7503 OCT 47.0 22.5 4.3 18.0 12.7 6.3 2029.8337 NOV 42.6 21.3 3.8 17.7 12.5 6.3 2029.9170 DEC 37.4 19.7 3.5 17.4 12.2 6.1 2030.0003 JAN 34.4 18.0 2.8 16.3 11.8 6.0 2030.0837 FEB 32.4 16.4 2.0 14.9 11.2 6.0 2030.1670 MAR 31.8 15.1 1.6 13.7 10.8 6.1 2030.2503 APR 31.4 14.2 1.3 13.8 10.4 6.3 2030.3337 MAY 30.8 13.2 1.3 13.4 9.9 6.3 2030.4170 JUN 30.0 12.2 1.4 13.0 9.6 6.1 2030.5003 JUL 27.6 11.3 1.3 12.7 9.3 6.0 2030.5837 AUG 24.4 10.4 1.2 12.4 9.1 5.9 2030.6670 SEP 22.4 9.6 1.1 11.7 8.9 5.5 2030.7503 OCT 20.9 8.9 0.9 11.2 8.6 5.0 2030.8337 NOV 18.8 8.3 0.8 10.9 8.4 4.6 2030.9170 DEC 18.8 8.4 0.7 10.9 8.4 4.6 2031.0003 JAN 19.7 9.1 1.4 11.2 8.5 4.4 2031.0837 FEB 21.5 10.3 1.9 11.5 8.7 4.4 2031.1670 MAR 23.2 11.5 2.2 11.6 8.8 4.3 2031.2503 APR 25.8 12.6 2.8 11.8 8.9 4.0 2031.3337 MAY 28.6 13.8 2.9 12.0 9.0 3.8 2031.4170 JUN 33.2 15.4 3.5 12.1 9.0 3.7 2031.5003 JUL 36.7 17.2 4.6 12.2 9.1 3.6 2031.5837 AUG 40.4 19.1 5.2 12.5 9.3 3.5 2031.6670 SEP 45.8 21.3 5.7 12.9 9.6 3.5 2031.7503 OCT 52.8 23.7 6.2 13.3 10.0 3.8 2031.8337 NOV 63.0 26.6 6.1 13.8 10.4 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