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% 2020.0837 FEB 69.9 69.8 69.4 5.8 5.6 5.3 2020.1670 MAR 70.4 70.2 69.4 5.9 5.5 5.2 2020.2503 APR 70.8 70.5 69.5 6.0 5.5 4.9 2020.3337 MAY 71.3 70.9 69.4 6.1 5.5 4.9 2020.4170 JUN 72.1 71.4 69.6 6.4 5.6 4.7 2020.5003 JUL 72.9 72.0 69.4 6.9 5.6 4.4 2020.5837 AUG 73.6 72.7 69.5 7.4 5.6 4.3 2020.6670 SEP 75.2 73.5 69.6 7.6 5.6 4.1 2020.7503 OCT 76.4 74.4 69.5 7.7 5.8 4.1 2020.8337 NOV 77.7 75.5 69.6 7.9 6.0 4.2 2020.9170 DEC 79.7 76.7 69.6 8.0 6.0 4.4 2021.0003 JAN 81.3 78.1 69.4 8.0 5.9 4.2 2021.0837 FEB 83.2 79.7 69.2 7.9 5.9 3.9 2021.1670 MAR 86.0 81.5 69.2 8.0 5.8 3.8 2021.2503 APR 88.5 83.4 68.7 8.2 5.8 3.2 2021.3337 MAY 90.8 85.5 68.2 9.1 5.9 3.0 2021.4170 JUN 93.0 87.7 68.1 9.9 6.1 2.9 2021.5003 JUL 95.2 90.0 68.5 10.0 6.2 2.9 2021.5837 AUG 98.0 92.6 69.3 9.9 6.3 2.9 2021.6670 SEP 101.9 95.2 69.7 9.4 6.4 2.9 2021.7503 OCT 105.4 97.8 69.8 8.9 6.4 3.1 2021.8337 NOV 107.9 100.5 70.6 8.3 6.3 3.3 2021.9170 DEC 112.2 103.3 71.8 8.3 6.4 3.4 2022.0003 JAN 115.9 106.2 72.3 9.2 6.6 3.8 2022.0837 FEB 120.3 109.1 73.2 10.4 7.0 4.7 2022.1670 MAR 124.4 112.0 74.5 10.8 7.5 5.2 2022.2503 APR 125.9 114.9 75.8 10.7 7.9 5.5 2022.3337 MAY 130.1 118.0 77.5 10.9 8.2 5.7 2022.4170 JUN 136.1 120.9 78.9 11.5 8.4 5.5 2022.5003 JUL 140.2 123.3 80.7 12.1 8.5 5.1 2022.5837 AUG 141.3 125.3 82.0 12.3 8.7 4.9 2022.6670 SEP 142.6 127.5 82.8 12.8 9.0 5.1 2022.7503 OCT 146.1 129.9 83.6 13.7 9.4 5.3 2022.8337 NOV 151.9 132.3 82.6 14.3 9.6 4.9 2022.9170 DEC 158.9 134.4 82.8 14.6 9.6 4.5 2023.0003 JAN 162.8 136.3 83.3 14.5 9.9 4.1 2023.0837 FEB 162.2 138.1 84.2 14.1 10.2 3.9 2023.1670 MAR 160.3 139.6 85.3 13.8 10.2 3.8 2023.2503 APR 159.3 141.1 87.3 14.1 10.1 3.8 2023.3337 MAY 160.9 142.2 88.3 14.9 10.0 3.5 2023.4170 JUN 165.2 142.9 87.7 15.0 10.0 3.4 2023.5003 JUL 168.9 143.6 86.6 14.7 10.1 3.9 2023.5837 AUG 171.4 143.9 86.3 14.6 10.3 4.5 2023.6670 SEP 171.1 144.2 86.9 14.2 10.3 4.8 2023.7503 OCT 167.6 144.5 87.9 13.6 10.1 4.9 2023.8337 NOV 164.6 144.7 89.7 13.5 10.1 5.0 2023.9170 DEC 163.1 144.8 91.7 13.5 10.2 5.1 2024.0003 JAN 164.6 144.3 93.0 13.1 10.0 5.0 2024.0837 FEB 165.4 143.2 93.9 12.9 9.9 5.3 2024.1670 MAR 164.5 142.5 94.9 12.7 9.6 5.6 2024.2503 APR 161.6 142.3 95.8 12.7 9.1 5.5 2024.3337 MAY 159.0 142.6 96.8 12.9 9.0 5.4 2024.4170 JUN 157.6 143.0 98.0 13.9 9.0 5.1 2024.5003 JUL 158.8 143.1 99.4 14.9 9.1 5.1 2024.5837 AUG 161.0 142.9 100.3 15.4 9.2 5.5 2024.6670 SEP 161.2 142.6 100.7 16.2 9.2 5.6 2024.7503 OCT 160.9 142.2 101.5 16.3 9.2 5.3 2024.8337 NOV 163.2 142.1 100.9 15.8 9.4 5.6 2024.9170 DEC 160.3 141.8 99.9 15.8 9.4 5.7 2025.0003 JAN 158.8 141.1 99.7 15.0 9.4 5.9 2025.0837 FEB 155.9 140.0 100.1 13.3 9.4 5.6 2025.1670 MAR 154.6 138.5 100.0 13.3 9.6 5.6 2025.2503 APR 153.0 136.9 99.3 13.7 10.0 5.8 2025.3337 MAY 152.6 135.4 98.1 14.0 10.2 6.0 2025.4170 JUN 152.6 134.1 97.5 15.1 10.6 6.7 2025.5003 JUL 152.0 132.8 97.2 16.0 10.8 7.1 2025.5837 AUG 149.7 131.1 96.8 16.8 10.7 6.9 2025.6670 SEP 146.9 129.3 96.9 17.2 10.7 7.1 2025.7503 OCT 145.0 127.9 97.3 17.6 11.0 7.2 2025.8337 NOV 144.2 126.8 96.8 17.6 11.0 7.1 2025.9170 DEC 143.6 125.7 96.7 16.9 11.0 6.9 2026.0003 JAN 141.3 124.2 96.8 15.9 11.0 6.7 2026.0837 FEB 137.4 122.4 95.5 14.6 11.1 6.6 2026.1670 MAR 134.5 121.3 94.6 14.1 11.5 7.1 2026.2503 APR 132.1 120.3 92.8 14.7 11.9 7.6 2026.3337 MAY 128.9 119.0 90.8 15.3 12.1 8.4 2026.4170 JUN 126.8 117.5 90.2 15.5 12.2 8.2 2026.5003 JUL 125.8 115.8 90.1 15.1 12.4 8.4 2026.5837 AUG 125.1 114.2 89.3 15.8 12.5 8.9 2026.6670 SEP 125.1 112.7 88.2 17.2 12.6 9.2 2026.7503 OCT 122.3 110.8 86.9 18.0 12.7 9.9 2026.8337 NOV 118.1 108.9 85.9 18.4 13.0 9.2 2026.9170 DEC 114.8 107.2 85.7 18.2 13.2 9.0 2027.0003 JAN 113.5 105.6 85.5 18.2 13.4 8.7 2027.0837 FEB 111.8 104.0 85.0 18.2 13.5 8.3 2027.1670 MAR 109.7 102.6 85.0 18.3 13.4 8.1 2027.2503 APR 108.2 101.2 84.6 18.8 13.3 8.1 2027.3337 MAY 109.1 99.8 83.2 19.1 13.0 7.8 2027.4170 JUN 106.1 98.3 81.4 19.5 12.8 6.8 2027.5003 JUL 103.6 96.9 80.3 19.9 12.3 5.8 2027.5837 AUG 101.8 95.8 78.9 20.2 11.9 5.5 2027.6670 SEP 101.1 94.7 78.0 20.5 11.7 5.3 2027.7503 OCT 99.9 93.6 77.4 20.8 11.7 5.3 2027.8337 NOV 100.2 92.8 77.2 20.5 11.4 5.1 2027.9170 DEC 99.8 91.8 76.6 19.7 11.1 5.1 2028.0003 JAN 98.6 90.7 75.7 18.8 11.0 5.3 2028.0837 FEB 97.5 89.7 74.8 18.1 10.9 5.7 2028.1670 MAR 96.1 88.9 73.8 17.9 11.2 6.0 2028.2503 APR 96.2 88.0 73.4 17.6 11.3 5.4 2028.3337 MAY 96.1 86.9 73.1 17.5 11.5 4.9 2028.4170 JUN 94.8 85.9 72.7 17.3 11.8 5.0 2028.5003 JUL 92.4 85.1 72.4 17.8 12.0 5.5 2028.5837 AUG 91.1 84.3 72.3 18.2 11.9 6.0 2028.6670 SEP 89.4 83.4 72.1 18.4 11.9 6.4 2028.7503 OCT 87.5 82.4 71.8 18.6 11.7 6.4 2028.8337 NOV 86.2 81.4 71.5 18.4 11.7 6.6 2028.9170 DEC 86.5 80.7 71.4 18.2 11.9 6.8 2029.0003 JAN 85.3 80.1 71.3 17.9 12.2 7.1 2029.0837 FEB 83.4 79.5 71.2 17.3 12.4 7.3 2029.1670 MAR 81.9 78.7 70.9 16.5 12.4 7.3 2029.2503 APR 81.6 77.9 70.5 16.7 12.1 7.1 2029.3337 MAY 81.3 77.3 70.2 16.7 11.8 7.0 2029.4170 JUN 80.4 76.6 70.1 16.7 11.6 6.6 2029.5003 JUL 79.9 76.1 70.0 16.8 11.5 6.1 2029.5837 AUG 79.9 75.7 69.9 17.0 11.7 6.0 2029.6670 SEP 79.5 75.2 69.8 17.4 11.7 6.3 2029.7503 OCT 79.1 74.7 69.4 17.4 11.6 6.6 2029.8337 NOV 78.5 74.2 69.4 17.1 11.5 6.6 2029.9170 DEC 77.5 73.5 69.2 16.8 11.2 6.4 2030.0003 JAN 75.7 72.9 68.8 15.7 10.7 6.4 2030.0837 FEB 74.4 72.3 68.4 14.2 10.1 6.3 2030.1670 MAR 73.9 71.9 68.1 12.9 9.7 6.2 2030.2503 APR 73.9 71.6 68.1 13.0 9.4 6.1 2030.3337 MAY 73.8 71.2 68.0 12.7 9.0 6.0 2030.4170 JUN 73.1 70.9 67.9 12.4 8.7 5.9 2030.5003 JUL 72.4 70.6 67.5 12.2 8.5 5.7 2030.5837 AUG 72.2 70.3 67.3 11.9 8.3 5.3 2030.6670 SEP 71.9 70.0 67.1 11.1 8.0 4.7 2030.7503 OCT 71.7 69.8 66.9 10.6 7.8 4.2 2030.8337 NOV 71.4 69.6 66.9 10.4 7.6 3.9 2030.9170 DEC 71.4 69.6 66.9 10.4 7.7 3.9 2031.0003 JAN 71.6 69.8 66.9 10.7 7.8 3.8 2031.0837 FEB 72.2 70.1 67.0 11.1 8.0 3.9 2031.1670 MAR 72.9 70.5 67.2 11.2 8.2 3.8 2031.2503 APR 72.9 70.9 67.2 11.5 8.4 3.6 2031.3337 MAY 73.1 71.3 67.4 11.7 8.5 3.4 2031.4170 JUN 74.1 71.9 67.5 11.9 8.7 3.4 2031.5003 JUL 75.6 72.6 67.7 12.0 8.9 3.4 2031.5837 AUG 76.1 73.4 67.8 12.4 9.1 3.3 2031.6670 SEP 77.0 74.2 68.0 12.8 9.5 3.4 2031.7503 OCT 78.2 75.2 68.1 13.2 9.9 3.7 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