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% 2020.7503 OCT 75.9 75.7 74.9 6.7 6.0 5.7 2020.8337 NOV 77.5 77.0 75.6 7.6 6.3 5.6 2020.9170 DEC 79.4 78.5 76.5 8.0 6.4 5.5 2021.0003 JAN 81.4 80.1 77.4 8.1 6.5 5.2 2021.0837 FEB 83.8 82.0 78.1 8.8 6.5 4.9 2021.1670 MAR 87.1 84.1 78.4 9.4 6.6 4.4 2021.2503 APR 90.3 86.4 78.8 10.2 6.7 4.0 2021.3337 MAY 92.9 88.8 80.0 11.3 6.9 3.9 2021.4170 JUN 95.4 91.4 81.7 12.2 7.2 4.0 2021.5003 JUL 99.5 94.1 81.8 12.5 7.4 4.0 2021.5837 AUG 103.7 97.0 82.4 12.5 7.6 4.1 2021.6670 SEP 107.1 99.9 83.8 12.0 7.6 4.0 2021.7503 OCT 110.1 102.8 85.5 11.3 7.5 4.2 2021.8337 NOV 113.6 105.7 87.1 10.7 7.4 4.4 2021.9170 DEC 116.7 108.8 88.4 10.9 7.5 4.4 2022.0003 JAN 120.8 112.1 89.4 10.9 7.6 4.7 2022.0837 FEB 124.5 115.5 90.7 10.8 7.9 5.3 2022.1670 MAR 128.4 118.8 92.2 11.0 8.2 5.7 2022.2503 APR 131.7 121.9 93.8 10.9 8.5 6.3 2022.3337 MAY 134.4 125.3 95.9 11.0 8.7 6.6 2022.4170 JUN 138.3 128.4 98.0 11.6 9.0 6.2 2022.5003 JUL 141.6 130.9 99.2 12.4 9.2 5.9 2022.5837 AUG 144.5 133.1 99.6 12.6 9.4 5.8 2022.6670 SEP 148.3 135.5 100.1 13.0 9.7 5.9 2022.7503 OCT 155.3 138.1 101.9 13.9 10.1 6.1 2022.8337 NOV 160.0 140.6 103.2 14.6 10.3 5.8 2022.9170 DEC 163.6 143.0 103.6 15.1 10.5 5.6 2023.0003 JAN 167.2 144.9 103.8 15.5 10.8 5.3 2023.0837 FEB 169.9 146.7 105.8 16.0 10.9 4.9 2023.1670 MAR 171.5 148.3 108.6 16.3 11.0 4.9 2023.2503 APR 172.9 149.7 112.2 16.9 11.1 5.1 2023.3337 MAY 175.2 150.8 114.3 17.9 11.1 5.1 2023.4170 JUN 174.6 151.6 113.5 18.1 11.2 5.2 2023.5003 JUL 173.1 152.1 112.3 17.5 11.2 5.6 2023.5837 AUG 172.9 152.3 110.5 17.1 11.4 6.0 2023.6670 SEP 173.0 152.5 109.5 16.6 11.3 6.3 2023.7503 OCT 173.1 152.8 111.8 16.1 11.1 6.4 2023.8337 NOV 174.3 152.8 113.5 16.1 11.1 6.5 2023.9170 DEC 177.9 152.7 115.0 15.9 11.2 6.7 2024.0003 JAN 178.7 152.0 114.7 15.2 11.1 6.6 2024.0837 FEB 175.3 150.8 112.8 14.5 11.0 6.9 2024.1670 MAR 173.9 150.0 111.1 13.9 10.6 7.0 2024.2503 APR 176.7 149.7 108.7 13.4 10.1 6.4 2024.3337 MAY 175.2 150.0 106.5 13.5 10.0 6.1 2024.4170 JUN 174.1 150.4 105.2 14.4 10.0 5.8 2024.5003 JUL 175.5 150.3 103.8 15.3 10.1 5.6 2024.5837 AUG 175.3 150.1 100.2 15.8 10.2 5.7 2024.6670 SEP 173.1 149.7 96.9 16.6 10.2 5.6 2024.7503 OCT 170.2 149.3 93.3 16.7 10.2 5.6 2024.8337 NOV 169.6 149.1 91.5 16.2 10.4 6.3 2024.9170 DEC 167.9 148.7 90.4 15.9 10.3 6.9 2025.0003 JAN 167.7 147.9 88.9 14.9 10.1 6.9 2025.0837 FEB 167.4 146.7 88.0 15.0 10.1 6.9 2025.1670 MAR 165.3 145.0 86.5 15.0 10.4 7.5 2025.2503 APR 163.0 143.4 85.0 15.7 10.7 7.5 2025.3337 MAY 160.5 141.9 83.2 15.9 10.9 7.5 2025.4170 JUN 157.7 140.7 82.6 16.3 11.2 7.4 2025.5003 JUL 155.8 139.1 82.7 16.7 11.4 7.6 2025.5837 AUG 153.6 137.3 83.1 15.9 11.2 7.4 2025.6670 SEP 150.7 135.2 84.0 15.7 11.3 7.3 2025.7503 OCT 147.1 133.3 85.2 16.7 11.6 7.4 2025.8337 NOV 143.6 131.8 86.0 16.7 11.6 7.3 2025.9170 DEC 142.2 130.5 87.0 16.6 11.7 7.1 2026.0003 JAN 142.1 128.7 88.2 16.7 11.9 7.1 2026.0837 FEB 141.4 126.8 88.3 16.8 12.1 7.0 2026.1670 MAR 139.6 125.5 88.2 16.0 12.5 7.5 2026.2503 APR 137.5 124.4 88.1 16.1 12.8 8.0 2026.3337 MAY 134.9 123.0 87.5 16.8 13.1 8.9 2026.4170 JUN 133.1 121.3 86.8 17.2 13.4 9.1 2026.5003 JUL 131.9 119.4 86.5 17.1 13.7 9.6 2026.5837 AUG 130.3 117.5 86.0 17.2 13.8 9.7 2026.6670 SEP 129.1 115.8 85.1 18.4 13.8 9.7 2026.7503 OCT 128.0 113.8 83.9 19.0 13.7 9.7 2026.8337 NOV 124.9 111.9 82.9 19.2 13.8 10.0 2026.9170 DEC 122.8 110.3 82.7 19.2 14.0 10.0 2027.0003 JAN 121.8 108.7 82.7 19.5 14.1 10.3 2027.0837 FEB 120.6 107.1 82.3 19.2 13.9 9.8 2027.1670 MAR 117.6 105.5 82.4 19.2 13.8 9.5 2027.2503 APR 115.5 104.0 82.0 19.6 13.6 9.4 2027.3337 MAY 113.7 102.3 79.7 19.8 13.3 9.0 2027.4170 JUN 112.0 100.6 78.3 20.1 13.0 7.9 2027.5003 JUL 110.4 99.1 77.1 20.5 12.5 6.9 2027.5837 AUG 107.9 97.8 75.7 21.1 12.3 7.0 2027.6670 SEP 105.7 96.6 74.9 21.7 12.3 7.1 2027.7503 OCT 103.4 95.5 74.5 22.0 12.3 7.2 2027.8337 NOV 102.4 94.6 74.3 21.8 12.1 7.2 2027.9170 DEC 101.8 93.6 73.9 21.2 11.9 7.0 2028.0003 JAN 101.2 92.3 73.2 20.4 11.8 6.4 2028.0837 FEB 100.3 91.2 72.6 19.8 11.8 6.1 2028.1670 MAR 99.1 90.2 72.2 19.6 12.1 5.8 2028.2503 APR 98.9 89.1 72.0 19.3 12.2 5.2 2028.3337 MAY 98.2 87.9 71.6 19.2 12.4 4.8 2028.4170 JUN 97.5 86.8 71.2 19.0 12.7 4.9 2028.5003 JUL 96.1 86.0 70.9 18.5 12.8 5.4 2028.5837 AUG 94.9 85.1 70.7 18.6 12.6 5.8 2028.6670 SEP 92.9 84.1 70.3 18.8 12.5 6.2 2028.7503 OCT 90.8 83.0 69.8 18.9 12.3 6.2 2028.8337 NOV 89.4 82.0 69.7 18.7 12.3 6.4 2028.9170 DEC 88.2 81.3 69.7 18.5 12.5 6.7 2029.0003 JAN 86.8 80.7 69.8 18.3 12.7 7.2 2029.0837 FEB 86.0 80.0 69.8 17.7 13.0 7.5 2029.1670 MAR 85.3 79.3 69.7 16.9 13.0 7.7 2029.2503 APR 84.3 78.6 69.5 17.0 12.8 7.4 2029.3337 MAY 83.5 77.9 69.4 17.0 12.6 7.1 2029.4170 JUN 82.2 77.3 69.3 17.1 12.4 7.0 2029.5003 JUL 80.7 76.7 69.3 17.2 12.4 6.5 2029.5837 AUG 80.5 76.2 69.1 17.6 12.5 6.6 2029.6670 SEP 80.3 75.7 69.1 18.0 12.5 6.6 2029.7503 OCT 79.4 75.2 69.0 17.9 12.3 6.5 2029.8337 NOV 78.0 74.6 68.9 17.6 12.1 6.5 2029.9170 DEC 77.6 73.9 68.8 17.3 11.8 6.3 2030.0003 JAN 76.8 73.3 68.5 16.2 11.3 6.3 2030.0837 FEB 75.5 72.6 68.2 14.6 10.7 6.3 2030.1670 MAR 75.2 72.2 67.9 13.3 10.2 6.3 2030.2503 APR 74.5 71.8 67.8 13.3 9.8 6.1 2030.3337 MAY 73.2 71.5 67.7 12.9 9.3 5.9 2030.4170 JUN 73.0 71.2 67.6 12.6 9.0 5.8 2030.5003 JUL 72.5 70.9 67.6 12.4 8.9 5.7 2030.5837 AUG 72.1 70.6 67.6 12.1 8.7 5.3 2030.6670 SEP 71.7 70.3 67.6 11.4 8.5 4.8 2030.7503 OCT 71.6 70.1 67.4 10.9 8.3 4.4 2030.8337 NOV 71.5 69.9 67.3 10.7 8.1 4.1 2030.9170 DEC 71.5 69.9 67.3 10.8 8.2 4.1 2031.0003 JAN 71.7 70.0 67.2 11.0 8.3 4.0 2031.0837 FEB 72.3 70.3 67.3 11.4 8.5 4.0 2031.1670 MAR 73.0 70.7 67.4 11.5 8.6 4.0 2031.2503 APR 73.0 71.1 67.4 11.7 8.7 3.7 2031.3337 MAY 73.1 71.4 67.6 11.9 8.8 3.5 2031.4170 JUN 74.1 72.0 67.7 12.0 8.9 3.5 2031.5003 JUL 75.6 72.7 67.8 12.1 9.1 3.4 2031.5837 AUG 76.1 73.4 67.9 12.5 9.3 3.4 2031.6670 SEP 77.0 74.3 68.0 12.8 9.6 3.4 2031.7503 OCT 78.2 75.2 68.1 13.3 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