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% 2020.5837 AUG 75.2 74.9 74.1 5.7 5.2 5.0 2020.6670 SEP 76.9 75.9 74.4 5.8 5.2 4.8 2020.7503 OCT 78.4 77.1 74.9 6.4 5.4 4.9 2020.8337 NOV 79.7 78.6 75.9 7.2 5.7 4.8 2020.9170 DEC 82.1 80.4 77.4 7.7 5.8 4.6 2021.0003 JAN 84.4 82.2 78.4 7.8 5.8 4.2 2021.0837 FEB 86.6 84.4 79.3 8.4 5.9 4.0 2021.1670 MAR 89.4 86.8 80.3 9.0 5.9 3.7 2021.2503 APR 93.0 89.4 81.1 9.8 6.0 3.2 2021.3337 MAY 96.9 92.3 82.5 10.9 6.2 3.1 2021.4170 JUN 100.1 95.3 84.6 11.9 6.5 3.2 2021.5003 JUL 104.7 98.4 85.3 12.1 6.7 3.2 2021.5837 AUG 109.3 101.6 86.0 12.1 6.9 3.2 2021.6670 SEP 113.5 104.8 87.5 11.5 6.9 3.2 2021.7503 OCT 117.0 107.9 89.3 10.9 6.7 3.3 2021.8337 NOV 119.3 111.1 91.1 10.3 6.6 3.5 2021.9170 DEC 120.8 114.5 92.6 9.9 6.7 3.5 2022.0003 JAN 125.7 118.3 93.8 9.9 6.8 3.8 2022.0837 FEB 131.7 122.0 95.3 9.9 7.1 4.7 2022.1670 MAR 135.5 125.7 96.6 10.2 7.5 5.3 2022.2503 APR 138.4 129.1 98.6 10.1 7.8 5.6 2022.3337 MAY 141.8 132.7 101.0 10.1 8.0 5.7 2022.4170 JUN 144.9 136.1 103.1 10.7 8.2 5.2 2022.5003 JUL 147.9 138.5 104.3 11.5 8.5 4.9 2022.5837 AUG 149.7 140.9 104.7 11.7 8.6 4.8 2022.6670 SEP 154.9 143.4 105.4 12.2 9.0 5.0 2022.7503 OCT 160.9 146.2 107.2 13.1 9.5 5.3 2022.8337 NOV 165.3 148.9 108.3 13.9 9.7 5.0 2022.9170 DEC 169.1 151.3 108.8 14.3 9.8 4.7 2023.0003 JAN 172.7 153.2 110.1 14.8 10.2 4.5 2023.0837 FEB 175.4 154.9 113.1 15.4 10.4 4.2 2023.1670 MAR 176.9 156.4 116.2 15.7 10.5 4.2 2023.2503 APR 179.6 157.8 119.5 16.2 10.5 4.4 2023.3337 MAY 182.3 158.9 123.2 17.2 10.6 4.4 2023.4170 JUN 184.1 159.6 123.2 17.4 10.6 4.5 2023.5003 JUL 181.3 159.9 121.6 16.8 10.7 4.9 2023.5837 AUG 180.0 159.9 120.2 16.5 10.8 5.3 2023.6670 SEP 178.5 160.0 119.0 16.0 10.8 5.5 2023.7503 OCT 178.7 160.2 120.7 15.4 10.5 5.5 2023.8337 NOV 179.3 160.0 121.8 15.3 10.6 5.7 2023.9170 DEC 180.1 159.6 122.6 15.1 10.6 5.9 2024.0003 JAN 180.8 158.8 122.6 14.4 10.4 5.6 2024.0837 FEB 178.2 157.5 120.7 13.6 10.3 5.9 2024.1670 MAR 179.9 156.6 118.9 12.8 9.8 6.0 2024.2503 APR 182.7 156.2 116.2 12.4 9.3 5.8 2024.3337 MAY 180.4 156.5 114.0 12.5 9.1 5.6 2024.4170 JUN 178.0 156.8 112.7 13.5 9.1 5.3 2024.5003 JUL 177.8 156.7 111.3 14.4 9.1 5.2 2024.5837 AUG 179.6 156.3 107.9 14.9 9.2 5.4 2024.6670 SEP 179.0 155.9 104.6 15.6 9.2 5.3 2024.7503 OCT 177.1 155.4 101.2 15.7 9.2 5.2 2024.8337 NOV 175.7 155.2 99.9 15.3 9.4 5.6 2024.9170 DEC 175.5 154.7 99.0 15.0 9.3 5.5 2025.0003 JAN 173.4 153.8 97.6 14.0 9.1 5.8 2025.0837 FEB 171.0 152.6 96.6 13.5 9.1 5.8 2025.1670 MAR 167.5 150.8 94.8 13.5 9.4 6.6 2025.2503 APR 165.4 149.2 94.0 14.4 9.7 6.8 2025.3337 MAY 163.7 147.8 91.9 14.6 9.9 7.0 2025.4170 JUN 163.0 146.5 91.0 15.0 10.3 6.9 2025.5003 JUL 161.7 144.7 90.7 15.5 10.5 7.2 2025.5837 AUG 158.8 142.7 90.7 14.7 10.3 7.0 2025.6670 SEP 155.4 140.3 91.0 15.0 10.4 6.8 2025.7503 OCT 152.2 138.1 91.6 15.6 10.7 6.9 2025.8337 NOV 150.5 136.2 91.8 15.6 10.8 6.8 2025.9170 DEC 149.3 134.6 92.3 15.4 10.8 6.7 2026.0003 JAN 146.6 132.6 93.1 15.5 10.9 6.6 2026.0837 FEB 144.3 130.5 92.9 15.6 11.2 6.5 2026.1670 MAR 142.6 129.1 92.6 14.9 11.6 7.1 2026.2503 APR 139.6 127.8 92.3 14.9 12.0 7.6 2026.3337 MAY 137.0 126.3 91.9 15.6 12.3 8.4 2026.4170 JUN 134.9 124.5 91.3 16.0 12.6 8.3 2026.5003 JUL 133.2 122.4 90.9 15.9 12.9 8.7 2026.5837 AUG 132.1 120.2 90.9 16.3 13.1 9.2 2026.6670 SEP 131.2 118.3 89.8 17.6 13.1 9.3 2026.7503 OCT 130.5 116.4 88.4 18.3 13.0 9.4 2026.8337 NOV 127.7 114.5 87.3 18.6 13.3 9.7 2026.9170 DEC 124.7 112.8 86.2 18.8 13.5 9.8 2027.0003 JAN 123.3 111.3 85.5 19.2 13.6 9.9 2027.0837 FEB 121.4 109.6 84.9 18.9 13.5 9.3 2027.1670 MAR 119.1 107.9 84.7 19.0 13.4 9.1 2027.2503 APR 116.7 106.2 83.6 19.5 13.3 9.1 2027.3337 MAY 114.3 104.4 82.2 19.7 13.1 8.6 2027.4170 JUN 112.5 102.4 80.7 20.0 12.7 7.6 2027.5003 JUL 110.5 100.8 79.7 20.5 12.3 6.7 2027.5837 AUG 108.0 99.5 78.3 21.1 12.1 6.7 2027.6670 SEP 106.9 98.2 77.4 21.6 12.0 6.8 2027.7503 OCT 105.4 97.0 76.8 22.0 12.1 6.8 2027.8337 NOV 104.1 96.1 76.6 21.7 11.8 6.8 2027.9170 DEC 103.7 94.9 76.0 21.1 11.6 6.9 2028.0003 JAN 102.9 93.6 75.1 20.2 11.4 6.4 2028.0837 FEB 101.5 92.3 74.3 19.5 11.4 6.0 2028.1670 MAR 100.4 91.1 73.4 19.4 11.7 5.8 2028.2503 APR 100.4 89.9 73.0 19.0 11.8 5.1 2028.3337 MAY 99.6 88.5 72.7 18.9 12.1 4.7 2028.4170 JUN 98.6 87.4 72.4 18.7 12.3 4.7 2028.5003 JUL 96.7 86.5 72.0 18.2 12.4 5.3 2028.5837 AUG 95.1 85.5 71.7 18.4 12.3 5.7 2028.6670 SEP 93.1 84.5 71.4 18.6 12.2 6.1 2028.7503 OCT 90.1 83.4 71.0 18.7 12.0 6.0 2028.8337 NOV 89.7 82.4 70.9 18.5 12.0 6.2 2028.9170 DEC 88.8 81.8 70.9 18.3 12.1 6.5 2029.0003 JAN 87.3 81.1 70.9 18.1 12.5 7.0 2029.0837 FEB 85.8 80.5 71.0 17.5 12.7 7.3 2029.1670 MAR 84.9 79.8 70.9 16.7 12.7 7.3 2029.2503 APR 84.0 79.1 70.8 16.7 12.4 7.1 2029.3337 MAY 83.2 78.5 70.6 16.7 12.1 6.9 2029.4170 JUN 81.9 77.8 70.5 16.7 11.9 6.5 2029.5003 JUL 81.4 77.2 70.3 16.8 11.8 6.0 2029.5837 AUG 80.9 76.6 70.1 17.3 12.0 6.0 2029.6670 SEP 80.6 76.0 70.0 17.7 12.0 6.4 2029.7503 OCT 79.9 75.5 69.7 17.6 11.9 6.6 2029.8337 NOV 78.5 74.9 69.6 17.3 11.7 6.6 2029.9170 DEC 78.0 74.2 69.3 17.0 11.4 6.4 2030.0003 JAN 76.6 73.5 68.9 15.9 10.9 6.4 2030.0837 FEB 75.3 72.9 68.5 14.3 10.3 6.3 2030.1670 MAR 75.0 72.4 68.3 13.0 9.8 6.0 2030.2503 APR 74.8 72.0 68.1 13.1 9.4 5.8 2030.3337 MAY 73.5 71.7 68.0 12.8 9.0 5.7 2030.4170 JUN 72.9 71.4 67.9 12.4 8.8 5.6 2030.5003 JUL 72.7 71.1 68.0 12.3 8.7 5.5 2030.5837 AUG 72.4 70.8 67.9 12.0 8.5 5.2 2030.6670 SEP 71.9 70.5 67.7 11.3 8.3 4.7 2030.7503 OCT 71.8 70.3 67.4 10.8 8.1 4.2 2030.8337 NOV 71.7 70.1 67.3 10.6 7.9 3.9 2030.9170 DEC 71.7 70.1 67.3 10.6 7.9 4.0 2031.0003 JAN 71.8 70.2 67.3 10.9 8.1 3.8 2031.0837 FEB 72.4 70.5 67.3 11.2 8.3 3.9 2031.1670 MAR 73.1 70.9 67.4 11.4 8.4 3.8 2031.2503 APR 73.1 71.2 67.5 11.6 8.6 3.6 2031.3337 MAY 73.2 71.6 67.6 11.8 8.7 3.4 2031.4170 JUN 74.2 72.1 67.7 11.9 8.8 3.4 2031.5003 JUL 75.7 72.8 67.8 12.1 9.0 3.4 2031.5837 AUG 76.1 73.5 67.9 12.4 9.2 3.3 2031.6670 SEP 77.0 74.3 68.0 12.8 9.5 3.4 2031.7503 OCT 78.2 75.3 68.1 13.2 10.0 3.7 2031.8337 NOV 80.0 76.4 68.4 13.8 10.4 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