TABLE 5 ESTIMATES OF 13-MONTH SMOOTH SOLAR ACTIVITY FOR BALANCE OF CYCLE 25 WITH A MEAN CYCLE GIVEN FOR CYCLE 26 TIME 10.7 CM SOLAR FLUX (F10.7) GEOMAGNETIC INDEX (Ap) PERCENTILE PERCENTILE 75.0% 50% 5.0% 95.0% 50% 5.0% 2021.6670 SEP 88.7 87.9 86.0 9.0 7.9 7.3 2021.7503 OCT 91.5 90.1 86.8 10.3 8.1 7.1 2021.8337 NOV 95.1 92.4 87.7 10.8 8.1 6.8 2021.9170 DEC 98.3 94.8 88.4 11.2 8.3 6.5 2022.0003 JAN 101.4 97.2 88.4 11.5 8.5 6.6 2022.0837 FEB 105.1 99.7 87.7 12.2 8.9 6.5 2022.1670 MAR 108.5 102.1 87.7 13.2 9.4 6.7 2022.2503 APR 111.1 104.8 87.1 14.0 9.9 6.9 2022.3337 MAY 114.4 107.5 87.2 14.7 10.3 7.2 2022.4170 JUN 118.6 110.3 87.3 15.1 10.6 7.6 2022.5003 JUL 122.8 112.8 86.9 14.8 10.7 7.7 2022.5837 AUG 125.5 114.8 88.1 15.0 10.7 7.4 2022.6670 SEP 126.8 116.6 87.4 14.8 10.9 7.2 2022.7503 OCT 129.9 118.8 85.5 14.2 11.1 7.1 2022.8337 NOV 135.7 121.1 83.4 14.7 11.2 6.6 2022.9170 DEC 141.1 123.5 80.8 15.0 11.2 6.2 2023.0003 JAN 144.2 125.5 78.3 15.0 11.4 5.8 2023.0837 FEB 145.7 127.3 77.2 15.4 11.6 5.5 2023.1670 MAR 146.7 129.0 77.1 15.4 11.5 5.3 2023.2503 APR 149.3 130.7 78.6 15.3 11.4 5.2 2023.3337 MAY 150.1 132.1 79.5 16.1 11.3 4.9 2023.4170 JUN 150.8 133.2 79.4 16.2 11.2 4.7 2023.5003 JUL 149.9 134.2 79.1 15.9 11.3 5.2 2023.5837 AUG 150.5 134.7 77.7 15.8 11.5 5.8 2023.6670 SEP 154.0 135.2 77.0 15.5 11.5 6.3 2023.7503 OCT 157.6 135.8 79.1 15.1 11.4 6.5 2023.8337 NOV 160.9 136.4 81.3 15.0 11.4 6.6 2023.9170 DEC 164.3 136.7 82.8 14.8 11.4 6.7 2024.0003 JAN 162.5 136.3 82.0 14.9 11.4 6.8 2024.0837 FEB 161.4 135.3 80.6 15.4 11.6 7.5 2024.1670 MAR 158.4 134.9 79.9 15.5 11.4 7.9 2024.2503 APR 156.9 135.0 78.9 15.9 11.1 7.2 2024.3337 MAY 156.5 135.5 77.6 16.7 11.0 7.5 2024.4170 JUN 157.9 136.1 76.1 18.1 11.2 7.9 2024.5003 JUL 160.1 136.3 74.7 19.3 11.4 8.0 2024.5837 AUG 161.5 136.5 72.3 20.0 11.6 8.0 2024.6670 SEP 162.1 136.5 70.4 21.0 11.8 7.7 2024.7503 OCT 159.5 136.3 68.3 21.4 11.9 7.2 2024.8337 NOV 160.4 136.3 67.4 20.7 11.9 7.2 2024.9170 DEC 160.4 136.1 67.0 20.7 12.0 7.1 2025.0003 JAN 157.8 135.5 65.9 19.9 12.0 6.8 2025.0837 FEB 155.0 134.5 65.4 18.0 11.9 6.4 2025.1670 MAR 151.6 133.3 65.1 16.4 12.1 6.3 2025.2503 APR 150.9 132.0 65.3 16.2 12.5 6.7 2025.3337 MAY 149.9 130.9 65.1 16.5 12.7 7.1 2025.4170 JUN 149.6 130.0 66.0 17.3 12.8 7.6 2025.5003 JUL 148.7 129.0 67.3 18.1 12.9 7.8 2025.5837 AUG 146.2 127.6 69.0 18.9 12.8 7.5 2025.6670 SEP 143.4 126.2 71.2 19.3 12.8 7.5 2025.7503 OCT 141.1 125.1 73.6 19.7 13.0 7.9 2025.8337 NOV 139.6 124.3 75.3 19.6 13.0 7.7 2025.9170 DEC 140.0 123.6 77.1 19.1 13.2 7.6 2026.0003 JAN 139.9 122.2 78.9 18.1 13.2 7.5 2026.0837 FEB 137.2 120.7 79.7 16.8 13.2 7.4 2026.1670 MAR 135.2 119.7 80.3 16.9 13.4 7.7 2026.2503 APR 134.4 118.8 80.2 17.2 13.7 8.2 2026.3337 MAY 133.1 117.7 79.3 17.6 13.9 9.0 2026.4170 JUN 130.1 116.3 79.0 17.7 14.0 9.6 2026.5003 JUL 126.8 114.8 79.2 18.1 14.2 9.8 2026.5837 AUG 124.9 113.4 79.4 19.3 14.3 10.1 2026.6670 SEP 124.1 111.9 78.8 20.4 14.4 10.4 2026.7503 OCT 122.9 110.1 78.0 21.0 14.4 10.9 2026.8337 NOV 122.1 108.4 77.5 21.1 14.6 11.5 2026.9170 DEC 120.5 106.8 77.5 20.7 14.6 10.9 2027.0003 JAN 117.8 105.3 77.6 20.1 14.7 10.3 2027.0837 FEB 117.2 103.9 77.7 19.3 14.6 9.7 2027.1670 MAR 115.3 102.6 78.2 18.3 14.4 9.3 2027.2503 APR 114.2 101.5 78.3 18.3 14.0 8.8 2027.3337 MAY 112.8 100.2 77.4 18.3 13.6 8.2 2027.4170 JUN 111.0 98.8 76.3 18.4 13.3 6.9 2027.5003 JUL 109.4 97.5 75.4 18.5 12.8 5.7 2027.5837 AUG 106.6 96.3 74.1 18.4 12.3 5.2 2027.6670 SEP 105.1 95.1 73.3 18.5 12.0 4.9 2027.7503 OCT 103.3 94.1 72.9 18.6 11.9 4.7 2027.8337 NOV 102.6 93.1 72.6 18.1 11.7 4.5 2027.9170 DEC 100.8 92.1 72.2 17.5 11.5 4.7 2028.0003 JAN 99.2 91.1 71.7 16.9 11.4 5.0 2028.0837 FEB 98.6 90.1 71.4 16.4 11.4 5.5 2028.1670 MAR 98.4 89.5 71.5 16.3 11.6 5.8 2028.2503 APR 97.9 88.7 71.6 16.1 11.8 6.0 2028.3337 MAY 97.5 87.6 71.2 17.1 12.1 5.6 2028.4170 JUN 97.0 86.6 70.9 17.4 12.3 5.6 2028.5003 JUL 95.7 85.9 70.6 17.7 12.4 6.1 2028.5837 AUG 94.8 85.1 70.5 18.1 12.4 6.6 2028.6670 SEP 93.1 84.3 70.1 18.4 12.4 7.0 2028.7503 OCT 91.2 83.3 69.6 18.6 12.2 7.0 2028.8337 NOV 89.5 82.2 69.5 18.4 12.2 7.1 2028.9170 DEC 88.3 81.4 69.4 18.1 12.3 7.2 2029.0003 JAN 86.8 80.8 69.4 17.8 12.4 7.4 2029.0837 FEB 85.9 80.0 69.3 17.2 12.5 7.5 2029.1670 MAR 85.2 79.2 69.2 16.9 12.5 7.4 2029.2503 APR 83.9 78.3 68.8 17.2 12.3 7.3 2029.3337 MAY 82.8 77.6 68.6 17.3 12.1 7.1 2029.4170 JUN 81.6 76.9 68.5 17.4 12.0 7.0 2029.5003 JUL 80.5 76.3 68.5 17.4 11.9 6.5 2029.5837 AUG 80.1 75.9 68.5 17.5 12.1 6.4 2029.6670 SEP 80.0 75.4 68.5 17.7 12.1 6.7 2029.7503 OCT 79.1 75.0 68.5 17.6 12.0 6.5 2029.8337 NOV 77.6 74.4 68.5 17.4 11.9 6.5 2029.9170 DEC 77.2 73.7 68.5 17.1 11.6 6.3 2030.0003 JAN 76.6 73.0 68.3 16.0 11.2 6.3 2030.0837 FEB 75.5 72.4 68.0 14.5 10.7 6.2 2030.1670 MAR 75.0 72.0 67.8 13.3 10.3 6.3 2030.2503 APR 74.3 71.7 67.7 13.4 10.0 6.4 2030.3337 MAY 73.0 71.4 67.6 13.0 9.6 6.4 2030.4170 JUN 72.8 71.0 67.4 12.6 9.3 6.2 2030.5003 JUL 72.0 70.6 67.4 12.4 9.0 6.1 2030.5837 AUG 71.7 70.3 67.4 12.1 8.8 5.8 2030.6670 SEP 71.4 70.0 67.3 11.3 8.5 5.2 2030.7503 OCT 71.3 69.8 67.0 11.0 8.3 4.7 2030.8337 NOV 71.2 69.6 66.9 10.6 8.1 4.4 2030.9170 DEC 71.2 69.6 66.9 10.6 8.1 4.4 2031.0003 JAN 71.5 69.7 66.9 10.9 8.2 4.2 2031.0837 FEB 72.0 70.1 67.0 11.2 8.4 4.2 2031.1670 MAR 72.8 70.5 67.1 11.4 8.6 4.1 2031.2503 APR 72.8 70.9 67.2 11.6 8.7 3.9 2031.3337 MAY 73.0 71.3 67.4 11.8 8.8 3.7 2031.4170 JUN 74.0 71.9 67.5 11.9 8.9 3.6 2031.5003 JUL 75.5 72.6 67.7 12.1 9.0 3.5 2031.5837 AUG 76.0 73.4 67.8 12.4 9.3 3.4 2031.6670 SEP 76.9 74.2 68.0 12.8 9.5 3.5 2031.7503 OCT 78.2 75.2 68.1 13.2 10.0 3.8 2031.8337 NOV 80.0 76.4 68.4 13.8 10.3 4.2 2031.9170 DEC 82.5 77.8 68.5 14.6 10.6 4.5 2032.0003 JAN 85.7 79.4 68.5 15.7 10.9 4.7 2032.0837 FEB 88.4 81.1 68.5 16.1 11.1 4.8 2032.1670 MAR 91.6 83.1 68.5 16.3 11.3 5.0 2032.2503 APR 94.6 85.2 68.4 16.9 11.4 5.1 2032.3337 MAY 97.2 87.5 68.6 18.0 11.6 5.3 2032.4170 JUN 99.1 89.9 68.7 18.9 11.9 5.4 2032.5003 JUL 103.2 92.5 69.0 19.1 12.1 5.6 2032.5837 AUG 108.1 95.3 69.3 19.2 12.3 5.8 2032.6670 SEP 112.2 98.1 69.4 19.0 12.6 6.0 2032.7503 OCT 116.5 100.9 69.6 18.6 12.7 6.1 2032.8337 NOV 120.0 103.7 70.1 18.5 12.7 6.1 2032.9170 DEC 122.7 106.7 70.8 18.9 12.8 6.1 2033.0003 JAN 125.5 109.8 71.0 18.8 12.9 6.3 2033.0837 FEB 129.4 113.0 71.4 17.8 13.0 6.5 2033.1670 MAR 133.2 116.2 71.7 17.9 13.2 6.7 2033.2503 APR 137.5 119.3 72.3 18.4 13.4 7.1 2033.3337 MAY 143.0 122.6 73.1 19.1 13.7 7.0 2033.4170 JUN 148.7 125.6 73.5 19.6 14.2 7.0 2033.5003 JUL 153.5 128.1 74.3 20.3 14.5 7.1 2033.5837 AUG 157.2 130.2 74.9 20.3 14.5 7.2 2033.6670 SEP 163.0 132.5 75.3 20.3 14.6 7.7 2033.7503 OCT 169.0 135.1 75.8 20.5 14.7 8.1 2033.8337 NOV 173.9 137.6 76.2 20.8 14.8 8.0 2033.9170 DEC 179.8 139.9 76.5 21.2 14.8 8.0 2034.0003 JAN 181.7 141.9 76.5 21.3 14.6 8.4 2034.0837 FEB 184.2 143.7 76.5 21.4 14.6 8.6 2034.1670 MAR 185.0 145.3 76.8 21.6 14.6 8.4 2034.2503 APR 184.8 146.8 77.3 22.0 14.5 8.4 2034.3337 MAY 184.0 147.9 77.8 22.7 14.4 8.6 2034.4170 JUN 183.8 148.7 78.5 22.4 14.1 8.6 2034.5003 JUL 185.2 149.3 79.8 21.3 13.8 8.5 2034.5837 AUG 186.7 149.6 80.6 20.6 13.7 8.3 2034.6670 SEP 187.4 149.9 81.6 20.1 13.6 8.0 2034.7503 OCT 187.1 150.2 83.1 19.7 13.5 7.6 2034.8337 NOV 186.0 150.3 84.6 19.6 13.5 7.5 2034.9170 DEC 186.2 150.3 86.2 19.3 13.5 7.8 2035.0003 JAN 184.1 149.6 87.0 19.1 13.7 7.7 2035.0837 FEB 179.8 148.5 88.2 18.9 13.9 7.6 2035.1670 MAR 176.9 147.7 89.8 18.9 14.0 7.5 2035.2503 APR 178.6 147.5 90.9 19.5 13.9 7.2 2035.3337 MAY 178.2 147.8 93.0 20.4 14.0 7.1 2035.4170 JUN 175.8 148.2 94.3 22.0 14.4 7.1 2035.5003 JUL 173.7 148.2 95.7 23.4 14.7 7.1 2035.5837 AUG 172.3 148.0 96.0 24.0 14.9 7.3 2035.6670 SEP 171.0 147.6 95.6 25.1 15.1 7.3 2035.7503 OCT 169.2 147.2 95.5 25.7 15.3 7.0 2035.8337 NOV 165.4 147.0 97.0 24.9 15.3 7.1 2035.9170 DEC 162.4 146.6 97.8 24.8 15.3 6.7 2036.0003 JAN 159.9 145.8 97.3 24.0 15.3 6.3 2036.0837 FEB 157.8 144.6 96.5 22.2 15.3 6.1 2036.1670 MAR 155.7 143.1 96.4 22.5 15.5 6.3 2036.2503 APR 155.3 141.4 96.9 23.2 15.7 6.5 2036.3337 MAY 155.2 140.0 96.4 23.2 15.7 6.7 2036.4170 JUN 153.7 138.7 95.7 22.7 15.7 7.1 2036.5003 JUL 150.5 137.2 96.3 22.0 15.6 7.6 2036.5837 AUG 146.7 135.5 97.2 21.9 15.7 7.7 2036.6670 SEP 143.8 133.5 96.3 22.7 15.9 8.1 2036.7503 OCT 140.4 131.8 94.6 23.6 16.2 8.7 2036.8337 NOV 137.4 130.4 93.8 23.8 16.4 8.9 2036.9170 DEC 136.7 129.2 93.6 23.8 16.6 9.3 2037.0003 JAN 136.0 127.5 91.8 23.8 16.6 9.7 2037.0837 FEB 134.8 125.7 88.5 23.4 16.6 10.1 2037.1670 MAR 133.8 124.4 88.0 22.5 16.5 10.5 2037.2503 APR 134.1 123.3 88.7 22.7 16.4 10.7 2037.3337 MAY 132.8 121.9 87.3 22.9 16.5 11.5 2037.4170 JUN 130.7 120.3 86.3 23.0 16.6 11.7 2037.5003 JUL 129.7 118.5 85.7 22.4 16.7 11.9 2037.5837 AUG 129.1 116.7 84.9 21.5 16.5 11.9 2037.6670 SEP 126.6 115.0 83.7 21.2 16.3 11.7 2037.7503 OCT 125.2 113.1 82.7 21.7 16.1 11.4 2037.8337 NOV 124.7 111.2 82.3 21.7 16.1 11.5 2037.9170 DEC 123.6 109.6 82.2 22.1 16.1 11.4 2038.0003 JAN 122.1 108.0 82.0 22.5 16.2 11.2 2038.0837 FEB 120.1 106.4 81.0 22.3 16.2 11.0 2038.1670 MAR 118.3 104.8 80.6 22.3 16.0 10.8 2038.2503 APR 116.2 103.4 80.6 22.7 15.8 10.7 2038.3337 MAY 114.3 101.8 80.0 22.9 15.5 10.6 2038.4170 JUN 111.1 100.2 79.1 23.4 15.3 10.3 2038.5003 JUL 109.5 98.7 77.7 24.0 15.0 10.1 2038.5837 AUG 107.9 97.5 75.6 24.7 14.9 10.1 2038.6670 SEP 106.4 96.3 74.6 25.3 14.8 10.1 2038.7503 OCT 104.4 95.2 74.1 25.4 14.8 10.5 2038.8337 NOV 103.0 94.3 73.8 25.3 14.7 10.4 2038.9170 DEC 102.0 93.3 73.5 24.8 14.5 10.2 2039.0003 JAN 100.5 92.1 73.1 23.9 14.3 10.0 2039.0837 FEB 98.9 91.0 72.7 23.0 14.1 9.4 2039.1670 MAR 98.2 90.0 72.0 22.5 14.2 8.8 2039.2503 APR 97.9 89.0 71.4 22.1 14.2 8.1 2039.3337 MAY 97.5 87.8 71.1 21.8 14.3 7.5 2039.4170 JUN 97.0 86.8 70.8 21.4 14.5 7.4 2039.5003 JUL 95.7 85.9 70.6 20.8 14.4 7.7 2039.5837 AUG 94.8 85.1 70.6 20.0 14.3 8.1 2039.6670 SEP 93.0 84.1 70.4 20.0 14.1 8.5 2039.7503 OCT 90.8 83.0 69.9 20.2 13.9 8.5 2039.8337 NOV 89.4 82.0 69.6 19.8 13.7 8.5 2039.9170 DEC 88.2 81.3 69.5 19.4 13.6 8.4 2040.0003 JAN 86.7 80.6 69.5 18.9 13.6 8.4 2040.0837 FEB 85.9 80.0 69.3 18.2 13.6 8.1 2040.1670 MAR 85.2 79.2 69.2 17.3 13.5 7.7 2040.2503 APR 83.9 78.5 68.8 17.3 13.3 7.1 2040.3337 MAY 82.8 77.8 68.6 17.4 13.2 6.8 2040.4170 JUN 81.8 77.2 68.4 17.5 13.1 6.6 2040.5003 JUL 81.2 76.6 68.4 17.5 12.9 6.5 2040.5837 AUG 80.7 76.1 68.5 17.7 12.9 6.6 2040.6670 SEP 80.5 75.6 68.5 18.0 12.7 6.5 2040.7503 OCT 79.2 75.1 68.5 17.9 12.6 6.4 2040.8337 NOV 77.9 74.6 68.4 17.6 12.3 6.4 2040.9170 DEC 77.2 73.9 68.3 17.3 12.0 6.2 2041.0003 JAN 76.7 73.2 68.0 16.3 11.7 6.1 2041.0837 FEB 75.8 72.6 67.8 14.9 11.2 6.0 2041.1670 MAR 75.3 72.1 67.7 13.8 10.9 6.1 2041.2503 APR 74.4 71.8 67.6 13.9 10.5 6.2 2041.3337 MAY 73.3 71.5 67.5 13.6 10.2 6.2 2041.4170 JUN 73.2 71.1 67.3 13.2 9.8 6.0 2041.5003 JUL 72.4 70.8 67.1 12.9 9.5 5.9 2041.5837 AUG 71.7 70.5 67.1 12.6 9.3 5.8 2041.6670 SEP 71.6 70.2 67.0 11.9 9.1 5.7 2041.7503 OCT 71.8 70.0 67.0 11.4 8.9 5.2