TABLE 3 ESTIMATES OF 13-MONTH SMOOTH SOLAR ACTIVITY FOR BALANCE OF CYCLE 24 WITH A MEAN CYCLE GIVEN FOR CYCLE 25 TIME 10.7 CM SOLAR FLUX (F10.7) GEOMAGNETIC INDEX (Ap) PERCENTILE PERCENTILE 95.0% 50% 5.0% 95.0% 50% 5.0% 2017.9170 DEC 76.4 74.6 71.9 9.8 9.0 8.4 2018.0003 JAN 77.7 74.3 69.6 10.9 9.1 7.9 2018.0837 FEB 78.9 74.2 68.6 11.9 9.4 7.4 2018.1670 MAR 79.5 73.9 68.2 13.0 9.6 6.8 2018.2503 APR 79.9 73.7 68.0 13.8 10.0 6.5 2018.3337 MAY 79.9 73.3 67.9 14.5 10.5 6.8 2018.4170 JUN 79.3 73.0 67.8 14.8 10.7 7.0 2018.5003 JUL 78.8 72.8 67.7 15.1 10.9 7.5 2018.5837 AUG 78.3 72.5 67.7 15.7 11.2 7.9 2018.6670 SEP 77.8 72.2 67.6 16.1 11.1 7.8 2018.7503 OCT 77.3 72.0 67.5 16.0 10.9 7.7 2018.8337 NOV 76.8 71.7 67.5 15.6 10.6 7.7 2018.9170 DEC 76.4 71.5 67.4 15.1 10.4 7.6 2019.0003 JAN 75.9 71.3 67.3 14.6 10.2 7.5 2019.0837 FEB 75.5 71.0 67.3 14.1 10.0 7.4 2019.1670 MAR 75.1 70.8 67.2 13.6 9.8 7.4 2019.2503 APR 74.7 70.6 67.2 13.1 9.7 7.3 2019.3337 MAY 74.4 70.5 67.2 12.7 9.5 7.2 2019.4170 JUN 74.1 70.3 67.1 12.3 9.4 7.1 2019.5003 JUL 73.8 70.2 67.1 11.9 9.3 7.1 2019.5837 AUG 73.6 70.1 67.1 11.6 9.2 7.0 2019.6670 SEP 73.5 70.0 67.0 11.4 9.1 7.0 2019.7503 OCT 73.3 69.9 67.0 11.2 9.0 7.0 2019.8337 NOV 73.2 69.9 67.0 11.1 9.0 7.0 2019.9170 DEC 73.2 69.9 67.0 11.1 9.0 6.9 2020.0003 JAN 73.3 70.0 67.0 11.3 9.0 6.9 2020.0837 FEB 74.0 70.3 67.1 11.6 9.2 7.1 2020.1670 MAR 74.8 70.7 67.2 11.7 9.3 7.4 2020.2503 APR 75.6 71.0 67.2 11.9 9.4 7.5 2020.3337 MAY 76.7 71.5 67.4 12.0 9.5 7.5 2020.4170 JUN 78.2 72.0 67.5 12.1 9.6 7.3 2020.5003 JUL 79.6 72.6 67.6 12.2 9.7 7.2 2020.5837 AUG 81.0 73.3 67.8 12.5 9.9 7.1 2020.6670 SEP 83.3 74.1 67.9 12.8 10.1 7.0 2020.7503 OCT 86.3 75.1 68.0 13.2 10.5 7.2 2020.8337 NOV 91.0 76.3 68.3 13.7 10.8 7.6 2020.9170 DEC 95.4 77.7 68.4 14.5 11.1 7.9 2021.0003 JAN 98.8 79.2 68.4 15.7 11.4 7.7 2021.0837 FEB 103.9 80.9 68.4 16.1 11.6 7.7 2021.1670 MAR 109.8 82.9 68.4 16.3 11.8 7.6 2021.2503 APR 115.6 85.1 68.3 16.8 12.0 7.6 2021.3337 MAY 122.9 87.3 68.6 18.0 12.3 7.6 2021.4170 JUN 131.3 89.9 68.7 18.9 12.6 7.7 2021.5003 JUL 137.8 92.6 68.9 19.1 12.7 7.7 2021.5837 AUG 142.5 95.4 69.2 19.2 12.9 7.8 2021.6670 SEP 146.9 98.2 69.2 19.0 13.1 7.7 2021.7503 OCT 151.3 101.0 69.5 18.6 13.1 7.7 2021.8337 NOV 156.2 103.9 69.9 18.5 13.2 7.8 2021.9170 DEC 161.5 107.0 70.6 18.9 13.4 8.0 2022.0003 JAN 166.8 110.1 70.9 18.8 13.5 8.2 2022.0837 FEB 171.3 113.2 71.3 17.8 13.5 8.6 2022.1670 MAR 177.2 116.5 71.5 17.9 13.7 8.7 2022.2503 APR 184.7 119.7 72.1 18.5 13.9 8.7 2022.3337 MAY 189.7 122.9 72.9 19.1 14.2 9.0 2022.4170 JUN 192.2 125.7 73.3 19.6 14.6 9.4 2022.5003 JUL 194.8 128.2 74.1 20.3 14.9 9.6 2022.5837 AUG 197.9 130.5 74.7 20.3 15.1 9.6 2022.6670 SEP 202.4 132.6 75.1 20.3 15.1 9.8 2022.7503 OCT 208.5 135.1 75.6 20.5 15.2 10.0 2022.8337 NOV 212.6 137.7 75.9 20.8 15.4 10.5 2022.9170 DEC 215.4 140.3 76.1 21.2 15.4 11.1 2023.0003 JAN 219.9 142.4 76.1 21.3 15.3 11.6 2023.0837 FEB 224.3 144.3 76.0 21.4 15.1 11.3 2023.1670 MAR 226.4 146.0 76.1 21.6 15.0 11.2 2023.2503 APR 227.3 147.7 76.6 22.0 15.0 10.7 2023.3337 MAY 229.2 149.0 76.9 22.8 14.9 10.2 2023.4170 JUN 231.4 149.9 77.6 22.5 14.7 9.9 2023.5003 JUL 234.2 150.8 78.9 21.3 14.5 10.1 2023.5837 AUG 237.3 151.2 79.7 20.6 14.3 10.1 2023.6670 SEP 238.6 151.4 80.6 20.1 14.2 10.3 2023.7503 OCT 236.8 151.7 82.2 19.6 14.1 10.6 2023.8337 NOV 234.8 151.9 83.8 19.5 14.0 10.6 2023.9170 DEC 235.8 152.0 85.6 19.3 14.0 10.5 2024.0003 JAN 236.3 151.2 86.4 19.1 14.2 10.5 2024.0837 FEB 234.1 149.7 87.8 18.9 14.6 10.5 2024.1670 MAR 230.9 148.7 89.5 18.9 14.7 10.3 2024.2503 APR 227.3 148.4 90.7 19.5 14.6 9.8 2024.3337 MAY 225.6 148.5 93.0 20.4 14.7 10.2 2024.4170 JUN 226.0 148.9 94.2 22.0 15.0 10.7 2024.5003 JUL 226.2 149.0 95.5 23.4 15.3 10.7 2024.5837 AUG 225.0 148.7 95.8 24.0 15.4 10.9 2024.6670 SEP 223.5 148.1 95.4 25.1 15.7 11.1 2024.7503 OCT 223.0 147.5 95.4 25.6 15.9 11.3 2024.8337 NOV 223.0 147.3 96.9 24.9 15.9 11.5 2024.9170 DEC 222.6 147.2 97.7 24.8 15.9 11.7 2025.0003 JAN 221.7 146.4 97.2 23.9 15.8 11.9 2025.0837 FEB 219.4 145.1 96.4 22.1 15.8 11.8 2025.1670 MAR 216.2 143.5 96.3 22.4 15.9 12.0 2025.2503 APR 213.5 141.8 96.8 23.1 16.0 11.8 2025.3337 MAY 210.9 140.1 96.3 23.1 16.0 11.1 2025.4170 JUN 207.5 138.8 95.5 22.6 16.0 10.8 2025.5003 JUL 206.4 137.4 96.1 22.0 15.8 10.8 2025.5837 AUG 204.4 135.6 97.1 21.9 15.8 10.8 2025.6670 SEP 201.0 133.7 96.2 22.7 16.1 10.8 2025.7503 OCT 197.5 132.2 94.5 23.7 16.5 10.8 2025.8337 NOV 195.1 130.9 93.8 23.9 16.7 10.8 2025.9170 DEC 193.0 129.5 93.6 23.9 17.0 10.7 2026.0003 JAN 189.1 127.8 91.7 23.9 17.1 10.6 2026.0837 FEB 184.5 125.9 88.3 23.5 17.2 10.3 2026.1670 MAR 180.1 124.6 87.9 22.5 17.2 10.5 2026.2503 APR 176.3 123.5 88.7 22.7 17.2 10.7 2026.3337 MAY 174.0 122.3 87.3 23.0 17.4 11.4 2026.4170 JUN 172.1 121.0 86.3 23.1 17.6 11.9 2026.5003 JUL 167.8 119.3 85.7 22.5 17.8 12.0 2026.5837 AUG 161.4 117.4 84.8 21.7 17.6 12.1 2026.6670 SEP 155.5 115.6 83.6 21.2 17.4 12.3 2026.7503 OCT 151.9 113.7 82.5 21.7 17.0 12.5 2026.8337 NOV 149.6 111.7 82.1 21.7 16.9 13.3 2026.9170 DEC 147.1 110.0 82.1 22.1 16.9 13.1 2027.0003 JAN 144.1 108.6 82.0 22.6 17.0 12.8 2027.0837 FEB 141.1 107.0 80.9 22.3 16.8 13.1 2027.1670 MAR 137.5 105.5 80.5 22.4 16.5 12.7 2027.2503 APR 133.8 104.0 80.6 22.7 16.2 12.5 2027.3337 MAY 129.6 102.5 80.0 22.9 15.8 12.1 2027.4170 JUN 123.6 100.9 79.1 23.5 15.6 11.2 2027.5003 JUL 119.4 99.4 77.7 24.1 15.4 10.5 2027.5837 AUG 118.6 98.2 75.6 24.8 15.3 10.7 2027.6670 SEP 118.7 97.1 74.5 25.3 15.3 10.8 2027.7503 OCT 119.2 96.1 74.0 25.6 15.3 10.6 2027.8337 NOV 119.6 95.2 73.6 25.4 15.3 10.8 2027.9170 DEC 118.8 94.2 73.4 24.9 15.2 11.0 2028.0003 JAN 117.4 92.9 73.0 24.0 15.0 11.1 2028.0837 FEB 115.8 91.7 72.7 23.0 14.9 11.3 2028.1670 MAR 113.7 90.7 71.9 22.5 15.0 11.2 2028.2503 APR 110.2 89.6 71.4 22.1 15.1 11.1 2028.3337 MAY 105.8 88.4 71.0 21.8 15.2 11.2 2028.4170 JUN 103.2 87.3 70.7 21.4 15.3 11.4 2028.5003 JUL 101.6 86.5 70.4 20.7 15.2 11.5 2028.5837 AUG 100.2 85.6 70.5 19.9 14.9 11.3 2028.6670 SEP 98.1 84.7 70.3 20.0 14.7 11.1 2028.7503 OCT 96.6 83.5 69.8 20.1 14.6 10.8 2028.8337 NOV 94.6 82.4 69.6 19.9 14.3 10.1 2028.9170 DEC 93.5 81.7 69.5 19.5 14.2 9.6 2029.0003 JAN 93.2 81.0 69.4 19.0 14.1 9.1 2029.0837 FEB 92.3 80.3 69.3 18.3 14.1 8.6 2029.1670 MAR 91.3 79.6 69.1 17.3 14.0 8.0 2029.2503 APR 90.5 78.9 68.8 17.4 13.8 7.5 2029.3337 MAY 89.7 78.2 68.5 17.5 13.7 7.6 2029.4170 JUN 88.7 77.5 68.3 17.6 13.7 7.8 2029.5003 JUL 87.7 77.0 68.4 17.5 13.6 8.3 2029.5837 AUG 86.9 76.5 68.4 17.7 13.5 8.6 2029.6670 SEP 85.5 75.9 68.5 18.1 13.4 8.5 2029.7503 OCT 84.1 75.4 68.4 17.9 13.2 8.6 2029.8337 NOV 82.2 74.9 68.4 17.6 12.9 8.5 2029.9170 DEC 79.9 74.2 68.3 17.3 12.6 8.5 2030.0003 JAN 78.4 73.5 68.0 16.3 12.2 8.4 2030.0837 FEB 77.5 72.8 67.8 14.8 11.8 8.4 2030.1670 MAR 77.0 72.3 67.6 13.8 11.4 8.3 2030.2503 APR 76.9 72.0 67.6 13.9 11.0 8.2 2030.3337 MAY 76.6 71.6 67.5 13.6 10.6 8.2 2030.4170 JUN 76.5 71.2 67.2 13.2 10.3 7.9 2030.5003 JUL 76.1 70.9 67.1 12.9 9.9 7.4 2030.5837 AUG 75.1 70.6 67.1 12.6 9.7 7.1 2030.6670 SEP 74.2 70.3 67.0 11.9 9.5 7.3 2030.7503 OCT 74.0 70.1 67.0 11.4 9.4 7.1