TABLE 5 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 75.0% 50% 5.0% 95.0% 50% 5.0% 2018.3337 MAY 70.7 70.3 69.5 8.1 7.5 6.4 2018.4170 JUN 70.7 70.1 68.6 8.7 7.6 6.0 2018.5003 JUL 70.8 70.0 68.2 9.2 7.8 6.3 2018.5837 AUG 70.5 69.8 67.5 9.7 7.9 6.1 2018.6670 SEP 70.5 69.6 67.5 10.2 7.9 6.1 2018.7503 OCT 70.6 69.7 67.1 10.5 8.0 6.4 2018.8337 NOV 70.8 69.8 66.7 10.7 8.1 6.1 2018.9170 DEC 70.8 69.7 66.6 10.9 8.1 6.0 2019.0003 JAN 70.5 69.6 66.3 10.6 8.2 6.0 2019.0837 FEB 70.5 69.3 66.1 10.0 8.3 6.1 2019.1670 MAR 70.4 69.2 66.0 10.4 8.5 6.4 2019.2503 APR 70.4 69.0 65.6 10.7 8.6 6.4 2019.3337 MAY 70.1 68.9 65.2 10.9 8.6 6.4 2019.4170 JUN 69.7 68.7 65.2 10.6 8.3 6.1 2019.5003 JUL 69.7 68.7 65.6 10.1 7.9 5.8 2019.5837 AUG 69.8 68.7 66.0 9.7 7.6 5.4 2019.6670 SEP 70.0 68.6 66.2 9.6 7.7 5.3 2019.7503 OCT 69.9 68.5 66.3 9.5 7.7 5.4 2019.8337 NOV 69.6 68.3 66.2 9.2 7.7 5.3 2019.9170 DEC 69.6 68.3 66.2 9.2 7.7 5.3 2020.0003 JAN 70.1 68.4 66.2 9.5 7.8 5.3 2020.0837 FEB 70.3 68.8 66.3 9.8 7.9 5.5 2020.1670 MAR 71.0 69.1 66.4 9.9 8.1 5.8 2020.2503 APR 70.7 69.5 66.5 10.1 8.2 5.9 2020.3337 MAY 71.1 69.9 66.6 10.2 8.2 5.9 2020.4170 JUN 71.5 70.5 66.7 10.3 8.3 5.7 2020.5003 JUL 72.0 71.1 66.9 10.4 8.4 5.6 2020.5837 AUG 73.3 71.7 67.0 10.7 8.6 5.4 2020.6670 SEP 74.9 72.6 67.1 11.0 8.9 5.3 2020.7503 OCT 76.3 73.5 67.2 11.4 9.3 5.5 2020.8337 NOV 78.1 74.8 67.5 11.9 9.6 5.9 2020.9170 DEC 80.2 76.2 67.6 12.7 9.9 6.2 2021.0003 JAN 83.4 77.6 67.6 13.9 10.2 6.0 2021.0837 FEB 86.4 79.4 67.6 14.3 10.4 6.0 2021.1670 MAR 88.4 81.4 67.6 14.5 10.5 5.9 2021.2503 APR 90.4 83.5 67.5 15.0 10.7 5.9 2021.3337 MAY 93.8 85.8 67.8 16.2 11.0 6.0 2021.4170 JUN 97.3 88.3 67.9 17.1 11.3 6.0 2021.5003 JUL 101.7 91.0 68.2 17.3 11.4 6.0 2021.5837 AUG 106.7 93.9 68.4 17.4 11.7 6.1 2021.6670 SEP 110.2 96.7 68.5 17.2 11.8 6.0 2021.7503 OCT 114.7 99.5 68.7 16.8 11.9 6.0 2021.8337 NOV 119.0 102.4 69.2 16.7 12.0 6.1 2021.9170 DEC 122.3 105.5 69.8 17.1 12.1 6.3 2022.0003 JAN 124.9 108.5 70.1 17.0 12.2 6.5 2022.0837 FEB 127.4 111.7 70.5 16.0 12.3 6.9 2022.1670 MAR 131.5 115.0 70.7 16.1 12.5 7.0 2022.2503 APR 136.4 118.2 71.4 16.7 12.7 7.1 2022.3337 MAY 141.0 121.4 72.2 17.3 12.9 7.4 2022.4170 JUN 146.5 124.2 72.6 17.8 13.4 7.8 2022.5003 JUL 151.1 126.6 73.4 18.5 13.7 7.9 2022.5837 AUG 155.9 128.9 74.0 18.5 13.8 7.9 2022.6670 SEP 161.9 131.1 74.3 18.5 13.9 8.2 2022.7503 OCT 167.6 133.6 74.8 18.7 13.9 8.4 2022.8337 NOV 172.8 136.2 75.1 19.0 14.1 8.9 2022.9170 DEC 178.4 138.7 75.3 19.4 14.1 9.5 2023.0003 JAN 181.7 140.8 75.3 19.5 14.0 10.0 2023.0837 FEB 183.8 142.8 75.3 19.6 13.8 9.7 2023.1670 MAR 183.9 144.5 75.4 19.8 13.8 9.6 2023.2503 APR 183.4 146.1 75.8 20.2 13.7 9.0 2023.3337 MAY 182.4 147.5 76.2 21.0 13.6 8.6 2023.4170 JUN 182.8 148.3 76.9 20.7 13.4 8.3 2023.5003 JUL 185.5 149.2 78.2 19.5 13.2 8.4 2023.5837 AUG 188.3 149.7 78.9 18.8 13.1 8.5 2023.6670 SEP 189.9 149.9 79.9 18.3 13.0 8.7 2023.7503 OCT 190.0 150.2 81.4 17.8 12.8 8.9 2023.8337 NOV 189.6 150.4 83.0 17.7 12.7 8.9 2023.9170 DEC 188.0 150.5 84.8 17.5 12.8 8.8 2024.0003 JAN 184.7 149.6 85.7 17.3 13.0 8.8 2024.0837 FEB 180.4 148.1 87.0 17.1 13.3 8.8 2024.1670 MAR 175.6 147.2 88.7 17.1 13.4 8.6 2024.2503 APR 172.1 146.8 90.0 17.7 13.3 8.2 2024.3337 MAY 175.2 146.9 92.2 18.6 13.4 8.6 2024.4170 JUN 174.8 147.3 93.4 20.2 13.8 9.0 2024.5003 JUL 172.0 147.5 94.7 21.6 14.0 9.1 2024.5837 AUG 170.9 147.1 95.0 22.2 14.2 9.3 2024.6670 SEP 169.9 146.5 94.6 23.3 14.4 9.4 2024.7503 OCT 168.8 146.0 94.7 23.8 14.6 9.6 2024.8337 NOV 165.3 145.7 96.1 23.1 14.6 9.8 2024.9170 DEC 162.0 145.6 97.0 23.0 14.6 10.1 2025.0003 JAN 159.4 144.8 96.4 22.1 14.6 10.2 2025.0837 FEB 156.9 143.6 95.7 20.3 14.5 10.2 2025.1670 MAR 154.1 142.0 95.6 20.6 14.6 10.4 2025.2503 APR 153.9 140.2 96.1 21.3 14.7 10.1 2025.3337 MAY 154.6 138.6 95.6 21.3 14.8 9.4 2025.4170 JUN 153.1 137.3 94.7 20.8 14.7 9.1 2025.5003 JUL 149.4 135.9 95.4 20.2 14.6 9.1 2025.5837 AUG 145.3 134.1 96.3 20.1 14.6 9.1 2025.6670 SEP 142.4 132.2 95.5 20.9 14.9 9.1 2025.7503 OCT 143.1 130.7 93.8 21.9 15.2 9.2 2025.8337 NOV 140.5 129.3 93.0 22.1 15.5 9.2 2025.9170 DEC 135.2 128.0 92.8 22.1 15.7 9.1 2026.0003 JAN 132.5 126.2 90.9 22.1 15.9 8.9 2026.0837 FEB 133.1 124.4 87.5 21.7 15.9 8.7 2026.1670 MAR 132.2 123.0 87.1 20.7 16.0 8.8 2026.2503 APR 132.5 122.0 87.9 20.9 15.9 9.0 2026.3337 MAY 131.1 120.8 86.5 21.2 16.1 9.7 2026.4170 JUN 129.7 119.5 85.5 21.3 16.4 10.2 2026.5003 JUL 128.6 117.8 84.9 20.7 16.5 10.4 2026.5837 AUG 127.9 115.8 84.1 19.8 16.4 10.5 2026.6670 SEP 125.0 114.0 82.8 19.4 16.1 10.6 2026.7503 OCT 123.9 112.1 81.8 19.9 15.8 10.8 2026.8337 NOV 124.1 110.2 81.4 19.9 15.6 11.6 2026.9170 DEC 122.3 108.5 81.4 20.3 15.7 11.4 2027.0003 JAN 120.6 107.1 81.2 20.8 15.7 11.2 2027.0837 FEB 119.0 105.5 80.2 20.5 15.5 11.4 2027.1670 MAR 117.1 103.9 79.8 20.6 15.3 11.1 2027.2503 APR 114.6 102.5 79.8 20.9 15.0 10.9 2027.3337 MAY 113.4 101.0 79.2 21.1 14.6 10.4 2027.4170 JUN 112.4 99.4 78.3 21.6 14.3 9.6 2027.5003 JUL 110.1 97.9 76.9 22.3 14.1 8.8 2027.5837 AUG 106.3 96.7 74.8 23.0 14.0 9.0 2027.6670 SEP 104.8 95.6 73.8 23.5 14.0 9.1 2027.7503 OCT 103.2 94.6 73.2 23.7 14.1 9.0 2027.8337 NOV 102.5 93.7 72.9 23.6 14.0 9.1 2027.9170 DEC 100.7 92.6 72.7 23.1 13.9 9.3 2028.0003 JAN 99.0 91.4 72.3 22.2 13.7 9.5 2028.0837 FEB 97.3 90.2 71.9 21.2 13.6 9.6 2028.1670 MAR 96.5 89.2 71.2 20.7 13.8 9.5 2028.2503 APR 96.5 88.1 70.6 20.3 13.8 9.4 2028.3337 MAY 96.1 86.8 70.3 20.0 14.0 9.5 2028.4170 JUN 95.2 85.8 69.9 19.6 14.0 9.8 2028.5003 JUL 93.9 84.9 69.7 18.9 13.9 9.8 2028.5837 AUG 93.2 84.1 69.7 18.1 13.7 9.6 2028.6670 SEP 91.5 83.1 69.5 18.2 13.5 9.4 2028.7503 OCT 89.2 82.0 69.1 18.3 13.3 9.1 2028.8337 NOV 87.8 80.9 68.9 18.1 13.1 8.5 2028.9170 DEC 86.4 80.1 68.7 17.7 12.9 8.0 2029.0003 JAN 84.9 79.4 68.7 17.2 12.9 7.5 2029.0837 FEB 84.2 78.8 68.5 16.5 12.8 7.0 2029.1670 MAR 83.6 78.0 68.3 15.5 12.7 6.3 2029.2503 APR 82.5 77.3 68.0 15.6 12.5 5.9 2029.3337 MAY 81.1 76.7 67.8 15.7 12.4 6.0 2029.4170 JUN 80.0 76.0 67.6 15.8 12.4 6.2 2029.5003 JUL 79.5 75.4 67.6 15.7 12.3 6.6 2029.5837 AUG 79.2 74.9 67.7 15.9 12.3 6.9 2029.6670 SEP 79.0 74.4 67.7 16.2 12.1 6.9 2029.7503 OCT 77.6 73.9 67.7 16.1 11.9 6.9 2029.8337 NOV 76.2 73.3 67.6 15.8 11.7 6.8 2029.9170 DEC 75.6 72.6 67.6 15.5 11.4 6.8 2030.0003 JAN 75.0 71.9 67.3 14.5 10.9 6.7 2030.0837 FEB 74.0 71.3 67.0 13.0 10.5 6.7 2030.1670 MAR 73.8 70.8 66.8 12.0 10.1 6.6 2030.2503 APR 72.8 70.4 66.8 12.1 9.7 6.5 2030.3337 MAY 71.6 70.0 66.7 11.8 9.4 6.5 2030.4170 JUN 71.7 69.7 66.5 11.4 9.0 6.2 2030.5003 JUL 70.8 69.4 66.3 11.1 8.7 5.7 2030.5837 AUG 70.5 69.1 66.3 10.8 8.5 5.4 2030.6670 SEP 70.4 68.7 66.3 10.1 8.3 5.7 2030.7503 OCT 70.1 68.5 66.3 9.6 8.1 5.5