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% 2020.9170 DEC 77.2 76.9 76.0 6.9 6.5 6.2 2021.0003 JAN 78.9 78.2 76.5 7.5 6.5 5.7 2021.0837 FEB 80.9 79.8 77.1 8.2 6.5 5.0 2021.1670 MAR 83.9 81.6 77.8 8.8 6.6 4.4 2021.2503 APR 86.2 83.5 78.1 9.2 6.6 3.9 2021.3337 MAY 88.7 85.6 79.2 9.6 6.8 3.7 2021.4170 JUN 90.5 87.7 79.6 10.4 7.0 3.8 2021.5003 JUL 92.7 90.1 79.2 10.6 7.2 4.1 2021.5837 AUG 95.7 92.7 79.3 10.8 7.4 4.5 2021.6670 SEP 98.5 95.4 80.6 11.0 7.5 4.5 2021.7503 OCT 102.7 98.0 82.2 10.8 7.4 4.6 2021.8337 NOV 105.9 100.7 83.7 10.7 7.4 4.9 2021.9170 DEC 108.9 103.6 84.9 11.1 7.5 5.0 2022.0003 JAN 112.1 106.6 85.8 11.1 7.6 5.3 2022.0837 FEB 116.1 109.6 86.9 10.9 7.9 5.6 2022.1670 MAR 120.7 112.6 88.2 11.3 8.3 5.9 2022.2503 APR 124.5 115.6 89.7 11.2 8.6 6.6 2022.3337 MAY 126.8 118.8 91.5 11.3 8.9 6.7 2022.4170 JUN 129.3 121.7 93.4 11.9 9.2 6.3 2022.5003 JUL 132.7 124.2 94.7 12.9 9.4 6.1 2022.5837 AUG 136.3 126.3 95.0 13.0 9.5 5.9 2022.6670 SEP 141.8 128.5 95.3 13.4 9.8 6.0 2022.7503 OCT 147.0 131.0 96.0 14.2 10.2 6.1 2022.8337 NOV 152.1 133.4 96.5 14.9 10.4 5.9 2022.9170 DEC 156.6 135.8 96.2 15.3 10.6 5.7 2023.0003 JAN 159.3 137.8 95.9 15.8 10.9 5.4 2023.0837 FEB 159.1 139.6 96.1 16.3 11.0 5.0 2023.1670 MAR 159.2 141.3 96.8 16.6 11.1 4.9 2023.2503 APR 162.1 142.8 99.3 17.1 11.1 5.1 2023.3337 MAY 164.0 144.1 100.1 18.1 11.2 5.1 2023.4170 JUN 163.3 144.9 99.3 18.3 11.2 5.2 2023.5003 JUL 162.8 145.7 99.0 17.7 11.3 5.6 2023.5837 AUG 165.5 146.1 97.9 17.4 11.5 6.1 2023.6670 SEP 168.5 146.4 97.6 17.0 11.5 6.5 2023.7503 OCT 170.9 146.8 100.2 16.4 11.3 6.6 2023.8337 NOV 173.1 147.1 102.4 16.4 11.3 6.8 2023.9170 DEC 175.6 147.2 104.4 16.2 11.3 6.9 2024.0003 JAN 173.7 146.6 104.4 15.5 11.2 6.7 2024.0837 FEB 172.7 145.5 102.4 14.9 11.1 7.1 2024.1670 MAR 171.2 144.8 101.1 14.2 10.8 7.4 2024.2503 APR 170.9 144.6 99.3 13.7 10.3 6.8 2024.3337 MAY 171.5 145.0 97.4 13.8 10.2 6.5 2024.4170 JUN 169.9 145.4 95.6 14.5 10.2 6.2 2024.5003 JUL 169.1 145.4 93.7 15.5 10.3 6.0 2024.5837 AUG 168.5 145.3 90.8 16.0 10.4 6.2 2024.6670 SEP 169.7 145.0 87.8 16.9 10.5 6.2 2024.7503 OCT 168.7 144.6 84.5 17.1 10.5 6.2 2024.8337 NOV 170.0 144.4 82.8 16.6 10.7 7.0 2024.9170 DEC 168.8 144.1 82.0 16.3 10.6 7.2 2025.0003 JAN 167.3 143.3 80.7 15.4 10.5 6.7 2025.0837 FEB 164.3 142.2 80.0 15.2 10.6 6.5 2025.1670 MAR 160.7 140.7 78.8 15.7 10.9 6.6 2025.2503 APR 158.6 139.1 77.8 16.7 11.2 6.7 2025.3337 MAY 156.4 137.7 76.2 16.9 11.4 7.0 2025.4170 JUN 153.6 136.5 75.8 16.8 11.7 7.5 2025.5003 JUL 151.4 135.1 76.3 16.9 11.9 7.7 2025.5837 AUG 149.3 133.4 77.0 16.1 11.7 7.5 2025.6670 SEP 146.6 131.5 78.3 16.6 11.7 7.3 2025.7503 OCT 143.4 130.0 80.2 17.6 12.1 7.4 2025.8337 NOV 139.9 128.8 81.6 17.5 12.1 7.2 2025.9170 DEC 139.0 127.7 83.3 17.4 12.2 7.1 2026.0003 JAN 139.0 126.1 84.9 17.5 12.3 7.0 2026.0837 FEB 138.7 124.4 85.2 17.5 12.4 6.9 2026.1670 MAR 137.5 123.2 84.8 16.6 12.8 7.4 2026.2503 APR 136.3 122.1 84.1 16.4 13.0 7.9 2026.3337 MAY 134.7 120.8 83.0 17.0 13.2 8.8 2026.4170 JUN 130.4 119.3 82.5 17.4 13.6 9.3 2026.5003 JUL 129.8 117.5 82.6 17.2 13.8 9.7 2026.5837 AUG 126.7 115.9 82.7 17.5 13.9 9.9 2026.6670 SEP 125.6 114.2 82.1 18.7 13.9 9.8 2026.7503 OCT 125.0 112.4 81.1 19.3 13.7 9.9 2026.8337 NOV 122.4 110.5 80.3 19.4 13.8 10.0 2026.9170 DEC 120.6 108.8 80.1 19.1 13.9 9.9 2027.0003 JAN 119.6 107.3 80.0 18.5 13.9 10.1 2027.0837 FEB 119.3 105.7 79.7 18.0 13.7 9.6 2027.1670 MAR 116.5 104.2 79.9 18.0 13.5 9.3 2027.2503 APR 114.6 102.8 79.7 18.4 13.3 9.1 2027.3337 MAY 113.6 101.3 78.7 18.4 13.0 8.6 2027.4170 JUN 111.9 99.7 77.5 18.6 12.5 7.4 2027.5003 JUL 110.5 98.3 76.5 18.9 12.0 6.3 2027.5837 AUG 108.0 97.1 75.1 19.3 11.7 6.3 2027.6670 SEP 105.4 95.9 74.3 19.7 11.6 6.3 2027.7503 OCT 103.0 94.8 73.9 20.1 11.7 6.3 2027.8337 NOV 101.8 93.9 73.6 19.9 11.4 6.3 2027.9170 DEC 101.2 93.0 73.3 19.3 11.3 6.3 2028.0003 JAN 100.6 91.8 72.7 18.7 11.2 5.8 2028.0837 FEB 99.4 90.8 72.3 18.1 11.3 5.5 2028.1670 MAR 98.6 89.9 72.0 18.1 11.6 5.3 2028.2503 APR 98.2 88.9 71.7 17.8 11.7 4.7 2028.3337 MAY 97.5 87.8 71.2 17.8 12.0 4.3 2028.4170 JUN 97.0 86.8 70.8 17.7 12.3 4.4 2028.5003 JUL 95.7 86.0 70.5 17.8 12.4 4.9 2028.5837 AUG 94.5 85.1 70.2 18.2 12.3 5.5 2028.6670 SEP 93.0 84.2 69.8 18.5 12.2 5.9 2028.7503 OCT 91.2 83.1 69.4 18.6 12.1 6.0 2028.8337 NOV 89.3 82.1 69.3 18.5 12.2 6.3 2028.9170 DEC 88.1 81.4 69.4 18.3 12.3 6.6 2029.0003 JAN 86.7 80.7 69.4 18.1 12.6 7.0 2029.0837 FEB 85.9 80.0 69.4 17.6 12.9 7.4 2029.1670 MAR 85.3 79.2 69.3 16.8 13.0 7.6 2029.2503 APR 84.1 78.4 69.1 17.1 12.8 7.4 2029.3337 MAY 83.0 77.7 68.9 17.1 12.6 7.1 2029.4170 JUN 81.9 77.1 68.8 17.2 12.4 6.9 2029.5003 JUL 80.8 76.5 68.8 17.3 12.4 6.6 2029.5837 AUG 80.5 76.0 68.7 17.6 12.6 6.7 2029.6670 SEP 80.4 75.6 68.7 18.0 12.5 6.6 2029.7503 OCT 79.2 75.1 68.6 17.9 12.4 6.4 2029.8337 NOV 77.8 74.5 68.6 17.6 12.1 6.5 2029.9170 DEC 77.3 73.9 68.5 17.3 11.8 6.3 2030.0003 JAN 76.7 73.2 68.2 16.2 11.3 6.3 2030.0837 FEB 75.7 72.6 67.9 14.6 10.7 6.3 2030.1670 MAR 75.3 72.1 67.7 13.3 10.2 6.3 2030.2503 APR 74.4 71.8 67.6 13.2 9.7 6.1 2030.3337 MAY 73.3 71.5 67.5 12.8 9.3 5.9 2030.4170 JUN 73.1 71.1 67.4 12.5 9.0 5.7 2030.5003 JUL 72.4 70.8 67.4 12.3 8.8 5.6 2030.5837 AUG 71.8 70.5 67.4 12.0 8.6 5.2 2030.6670 SEP 71.5 70.2 67.4 11.3 8.4 4.7 2030.7503 OCT 71.5 70.0 67.4 10.8 8.2 4.3 2030.8337 NOV 71.4 69.8 67.3 10.6 8.0 3.9 2030.9170 DEC 71.4 69.8 67.2 10.6 8.1 4.0 2031.0003 JAN 71.6 69.9 67.2 10.9 8.2 3.9 2031.0837 FEB 72.2 70.2 67.3 11.2 8.4 3.9 2031.1670 MAR 72.9 70.6 67.4 11.4 8.5 3.9 2031.2503 APR 72.9 71.0 67.4 11.6 8.6 3.6 2031.3337 MAY 73.1 71.4 67.6 11.8 8.8 3.5 2031.4170 JUN 74.1 72.0 67.7 11.9 8.9 3.4 2031.5003 JUL 75.6 72.7 67.8 12.1 9.0 3.4 2031.5837 AUG 76.1 73.4 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 75.2 68.1 13.2 10.0 3.8 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