TABLE 4 ESTIMATES OF 13-MONTH SMOOTH SOLAR ACTIVITY FOR BALANCE OF CYCLE 24 AND CYCLE 25 TIME SUNSPOT NUMBERS GEOMAGNETIC INDEX (Ap) PERCENTILE PERCENTILE 95.0% 50% 5.0% 95.0% 50% 5.0% 2013.2503 APR 61.9 58.8 55.9 8.1 7.4 6.4 2013.3337 MAY 63.9 59.6 53.5 8.7 7.3 6.1 2013.4170 JUN 66.4 59.8 50.5 9.4 7.0 5.3 2013.5003 JUL 68.9 59.9 49.1 10.2 6.9 4.5 2013.5837 AUG 70.6 60.2 46.0 10.7 7.0 4.4 2013.6670 SEP 72.2 60.4 42.7 11.3 6.9 4.0 2013.7503 OCT 73.6 60.6 39.8 11.4 6.8 3.5 2013.8337 NOV 73.4 60.3 38.4 11.4 7.3 3.6 2013.9170 DEC 76.2 60.3 37.0 12.1 7.8 3.8 2014.0003 JAN 76.5 60.3 36.6 12.3 8.4 4.4 2014.0837 FEB 77.0 59.6 35.1 12.5 8.9 4.9 2014.1670 MAR 76.9 58.1 33.1 12.7 9.3 5.5 2014.2503 APR 76.9 56.9 31.7 12.9 9.6 6.1 2014.3337 MAY 77.9 56.3 30.9 13.3 9.8 6.6 2014.4170 JUN 80.1 55.9 30.4 14.0 10.5 7.7 2014.5003 JUL 82.2 55.0 30.3 15.3 11.1 8.5 2014.5837 AUG 83.2 53.9 30.3 16.3 11.3 8.7 2014.6670 SEP 83.2 53.5 30.4 17.0 11.5 8.8 2014.7503 OCT 83.1 53.4 30.7 17.3 11.7 8.3 2014.8337 NOV 83.1 53.3 30.9 17.3 11.7 8.1 2014.9170 DEC 84.8 52.3 29.6 17.7 11.8 8.4 2015.0003 JAN 86.0 51.2 28.3 18.5 12.1 8.4 2015.0837 FEB 84.9 50.5 27.4 18.8 12.6 8.6 2015.1670 MAR 83.1 49.9 25.9 19.3 13.3 8.9 2015.2503 APR 80.7 49.5 24.7 20.1 14.1 9.4 2015.3337 MAY 78.7 49.0 24.3 21.2 15.1 10.5 2015.4170 JUN 76.3 48.3 23.6 21.6 15.9 11.2 2015.5003 JUL 73.4 47.5 22.4 21.2 16.2 11.4 2015.5837 AUG 72.9 46.6 21.1 20.9 16.6 11.8 2015.6670 SEP 72.7 45.4 20.2 21.0 17.0 12.1 2015.7503 OCT 72.2 44.0 19.8 21.7 17.0 12.4 2015.8337 NOV 71.0 42.9 20.1 22.1 17.3 13.5 2015.9170 DEC 68.6 41.3 19.7 23.5 18.0 14.5 2016.0003 JAN 66.6 40.0 19.3 24.1 18.2 14.5 2016.0837 FEB 66.5 39.5 19.2 23.5 17.7 14.4 2016.1670 MAR 67.4 38.8 17.8 23.1 17.1 13.7 2016.2503 APR 68.1 37.7 14.8 22.9 16.4 12.8 2016.3337 MAY 69.0 36.9 12.6 22.7 15.7 11.8 2016.4170 JUN 69.3 36.1 11.1 23.3 15.5 11.0 2016.5003 JUL 68.0 35.0 10.2 23.7 15.1 10.0 2016.5837 AUG 67.4 33.8 9.2 23.8 14.4 9.3 2016.6670 SEP 66.0 32.6 8.0 23.9 14.1 8.9 2016.7503 OCT 63.3 31.2 7.4 24.1 14.2 8.8 2016.8337 NOV 60.9 29.7 6.8 24.3 14.3 9.3 2016.9170 DEC 59.3 28.3 5.7 24.0 14.5 9.9 2017.0003 JAN 58.9 27.3 4.8 23.6 14.7 10.7 2017.0837 FEB 58.6 26.9 4.4 23.5 15.3 11.9 2017.1670 MAR 57.3 26.3 4.4 24.0 16.2 12.4 2017.2503 APR 55.2 25.5 4.7 24.2 16.8 12.4 2017.3337 MAY 52.6 24.4 5.2 24.5 17.3 12.9 2017.4170 JUN 49.8 23.5 5.4 24.1 17.5 13.2 2017.5003 JUL 48.9 22.8 5.1 23.5 17.4 13.5 2017.5837 AUG 47.9 22.1 5.3 22.9 17.3 13.0 2017.6670 SEP 46.6 21.2 5.8 22.2 17.4 13.0 2017.7503 OCT 44.5 20.2 5.1 21.2 17.3 12.8 2017.8337 NOV 42.5 19.7 5.0 20.9 17.1 12.2 2017.9170 DEC 41.7 19.2 5.8 20.5 16.9 11.7 2018.0003 JAN 39.7 18.3 5.7 20.1 16.8 11.2 2018.0837 FEB 36.7 17.4 5.1 20.1 16.5 10.5 2018.1670 MAR 33.9 16.3 4.4 19.8 16.2 9.6 2018.2503 APR 32.0 15.3 3.8 19.0 15.5 8.8 2018.3337 MAY 30.5 14.6 3.5 18.5 15.1 8.6 2018.4170 JUN 29.1 13.9 3.2 18.6 15.1 8.9 2018.5003 JUL 27.6 13.3 2.9 19.2 15.4 9.5 2018.5837 AUG 26.2 12.6 2.7 19.6 15.4 9.9 2018.6670 SEP 24.8 11.9 2.4 20.0 15.3 10.0 2018.7503 OCT 23.4 11.3 2.1 20.0 15.2 10.1 2018.8337 NOV 22.1 10.7 1.9 19.6 14.9 9.9 2018.9170 DEC 20.8 10.1 1.6 18.6 14.3 9.6 2019.0003 JAN 19.6 9.5 1.4 17.7 13.6 9.3 2019.0837 FEB 18.4 9.0 1.2 16.7 12.9 8.9 2019.1670 MAR 17.4 8.5 1.0 15.8 12.3 8.6 2019.2503 APR 16.4 8.0 0.8 14.9 11.7 8.3 2019.3337 MAY 15.5 7.6 0.6 14.1 11.1 8.0 2019.4170 JUN 14.7 7.2 0.5 13.4 10.6 7.8 2019.5003 JUL 14.0 6.9 0.3 12.7 10.1 7.5 2019.5837 AUG 13.4 6.6 0.2 12.1 9.7 7.3 2019.6670 SEP 12.9 6.4 0.1 11.7 9.4 7.2 2019.7503 OCT 12.6 6.2 0.1 11.3 9.2 7.0 2019.8337 NOV 12.4 6.1 0.0 11.1 9.0 7.0 2019.9170 DEC 12.3 6.1 0.0 11.1 9.0 6.9 2020.0003 JAN 12.9 6.5 0.4 11.3 9.0 6.9 2020.0837 FEB 14.2 7.2 0.9 11.6 9.2 7.1 2020.1670 MAR 15.4 7.8 1.2 11.7 9.3 7.4 2020.2503 APR 16.6 8.5 1.7 11.9 9.4 7.5 2020.3337 MAY 18.1 9.3 1.8 12.0 9.5 7.5 2020.4170 JUN 20.6 10.2 2.3 12.1 9.6 7.3 2020.5003 JUL 23.0 11.2 2.9 12.2 9.7 7.2 2020.5837 AUG 25.1 12.3 3.1 12.5 9.9 7.1 2020.6670 SEP 28.3 13.6 3.2 12.8 10.1 7.0 2020.7503 OCT 32.2 15.1 3.5 13.2 10.5 7.2 2020.8337 NOV 38.2 16.9 3.5 13.7 10.8 7.6 2020.9170 DEC 43.7 19.0 3.5 14.5 11.1 7.9 2021.0003 JAN 47.9 21.0 4.2 15.7 11.4 7.7 2021.0837 FEB 54.1 23.4 4.3 16.1 11.6 7.7 2021.1670 MAR 60.7 25.9 4.3 16.3 11.8 7.6 2021.2503 APR 66.8 28.4 4.8 16.8 12.0 7.6 2021.3337 MAY 74.4 31.2 4.8 18.0 12.3 7.6 2021.4170 JUN 83.1 34.5 5.2 18.9 12.6 7.7 2021.5003 JUL 89.9 37.8 5.8 19.1 12.7 7.7 2021.5837 AUG 95.1 41.3 6.8 19.2 12.9 7.8 2021.6670 SEP 100.0 44.8 7.7 19.0 13.1 7.7 2021.7503 OCT 105.0 48.2 9.1 18.6 13.1 7.7 2021.8337 NOV 110.5 51.5 9.8 18.5 13.2 7.8 2021.9170 DEC 116.5 54.9 9.9 18.9 13.4 8.0 2022.0003 JAN 122.0 58.5 11.2 18.8 13.5 8.2 2022.0837 FEB 126.8 62.1 12.4 17.8 13.5 8.6 2022.1670 MAR 134.1 65.8 13.4 17.9 13.7 8.7 2022.2503 APR 141.4 69.4 14.6 18.5 13.9 8.7 2022.3337 MAY 146.1 72.7 15.1 19.1 14.2 9.0 2022.4170 JUN 147.9 75.6 15.6 19.6 14.6 9.4 2022.5003 JUL 151.0 78.5 16.2 20.3 14.9 9.6 2022.5837 AUG 154.7 80.9 16.7 20.3 15.1 9.6 2022.6670 SEP 158.4 83.0 17.1 20.3 15.1 9.8 2022.7503 OCT 163.8 85.3 17.1 20.5 15.2 10.0 2022.8337 NOV 167.3 87.7 16.7 20.8 15.4 10.5 2022.9170 DEC 169.1 90.1 16.4 21.2 15.4 11.1 2023.0003 JAN 172.9 92.3 16.8 21.3 15.3 11.6 2023.0837 FEB 177.6 94.2 17.5 21.4 15.1 11.3 2023.1670 MAR 180.4 96.2 18.7 21.6 15.0 11.2 2023.2503 APR 182.4 98.4 20.6 22.0 15.0 10.7 2023.3337 MAY 185.0 100.2 21.8 22.8 14.9 10.2 2023.4170 JUN 187.4 101.3 23.1 22.5 14.7 9.9 2023.5003 JUL 189.5 102.2 25.4 21.3 14.5 10.1 2023.5837 AUG 190.7 102.4 28.1 20.6 14.3 10.1 2023.6670 SEP 192.2 102.8 30.7 20.1 14.2 10.3 2023.7503 OCT 192.5 103.6 32.1 19.6 14.1 10.6 2023.8337 NOV 192.1 104.1 33.4 19.5 14.0 10.6 2023.9170 DEC 193.4 104.4 35.7 19.3 14.0 10.5 2024.0003 JAN 193.9 103.6 37.4 19.1 14.2 10.5 2024.0837 FEB 190.8 102.1 39.6 18.9 14.6 10.5 2024.1670 MAR 186.3 101.2 41.2 18.9 14.7 10.3 2024.2503 APR 181.9 100.7 42.7 19.5 14.6 9.8 2024.3337 MAY 179.6 100.4 43.9 20.4 14.7 10.2 2024.4170 JUN 178.9 100.1 43.8 22.0 15.0 10.7 2024.5003 JUL 177.8 99.7 43.3 23.4 15.3 10.7 2024.5837 AUG 176.5 99.1 44.0 24.0 15.4 10.9 2024.6670 SEP 175.3 98.5 45.9 25.1 15.7 11.1 2024.7503 OCT 174.5 98.0 46.0 25.6 15.9 11.3 2024.8337 NOV 173.4 97.4 45.1 24.9 15.9 11.5 2024.9170 DEC 172.3 96.6 44.4 24.8 15.9 11.7 2025.0003 JAN 170.7 95.7 44.9 23.9 15.8 11.9 2025.0837 FEB 168.1 94.1 45.4 22.1 15.8 11.8 2025.1670 MAR 164.2 92.1 44.3 22.4 15.9 12.0 2025.2503 APR 161.0 90.3 43.7 23.1 16.0 11.8 2025.3337 MAY 157.9 89.1 44.7 23.1 16.0 11.1 2025.4170 JUN 153.9 87.8 45.7 22.6 16.0 10.8 2025.5003 JUL 150.5 86.2 44.6 22.0 15.8 10.8 2025.5837 AUG 146.4 84.3 42.6 21.9 15.8 10.8 2025.6670 SEP 142.9 82.9 41.6 22.7 16.1 10.8 2025.7503 OCT 142.0 81.8 41.3 23.7 16.5 10.8 2025.8337 NOV 138.7 80.3 39.3 23.9 16.7 10.8 2025.9170 DEC 136.4 78.4 35.0 23.9 17.0 10.7 2026.0003 JAN 135.3 76.6 34.1 23.9 17.1 10.6 2026.0837 FEB 132.3 74.9 35.4 23.5 17.2 10.3 2026.1670 MAR 128.8 73.5 34.6 22.5 17.2 10.5 2026.2503 APR 124.8 72.3 32.7 22.7 17.2 10.7 2026.3337 MAY 120.7 71.1 31.7 23.0 17.4 11.4 2026.4170 JUN 117.2 69.7 30.9 23.1 17.6 11.9 2026.5003 JUL 114.8 68.0 29.4 22.5 17.8 12.0 2026.5837 AUG 110.8 66.0 27.7 21.7 17.6 12.1 2026.6670 SEP 104.4 63.7 26.7 21.2 17.4 12.3 2026.7503 OCT 97.6 61.3 26.3 21.7 17.0 12.5 2026.8337 NOV 93.7 59.4 26.6 21.7 16.9 13.3 2026.9170 DEC 92.5 57.7 25.8 22.1 16.9 13.1 2027.0003 JAN 91.4 56.1 24.3 22.6 17.0 12.8 2027.0837 FEB 88.9 54.7 24.4 22.3 16.8 13.1 2027.1670 MAR 86.8 53.1 23.8 22.4 16.5 12.7 2027.2503 APR 83.1 51.4 22.7 22.7 16.2 12.5 2027.3337 MAY 79.8 49.8 21.9 22.9 15.8 12.1 2027.4170 JUN 76.3 48.2 20.4 23.5 15.6 11.2 2027.5003 JUL 71.0 46.4 18.9 24.1 15.4 10.5 2027.5837 AUG 69.8 44.7 16.7 24.8 15.3 10.7 2027.6670 SEP 70.1 43.5 14.9 25.3 15.3 10.8 2027.7503 OCT 69.7 42.3 13.7 25.6 15.3 10.6 2027.8337 NOV 69.6 41.1 11.9 25.4 15.3 10.8 2027.9170 DEC 68.8 39.7 10.4 24.9 15.2 11.0 2028.0003 JAN 66.8 38.2 9.5 24.0 15.0 11.1 2028.0837 FEB 64.1 36.8 8.7 23.0 14.9 11.3 2028.1670 MAR 60.9 35.5 7.9 22.5 15.0 11.2 2028.2503 APR 56.4 34.1 7.8 22.1 15.1 11.1 2028.3337 MAY 52.1 32.5 7.9 21.8 15.2 11.2 2028.4170 JUN 49.0 31.3 7.6 21.4 15.3 11.4 2028.5003 JUL 49.8 30.5 7.5 20.7 15.2 11.5 2028.5837 AUG 49.0 29.5 7.4 19.9 14.9 11.3 2028.6670 SEP 46.4 28.2 7.1 20.0 14.7 11.1 2028.7503 OCT 44.0 26.8 6.5 20.1 14.6 10.8 2028.8337 NOV 42.0 25.7 6.5 19.9 14.3 10.1 2028.9170 DEC 40.9 24.9 6.1 19.5 14.2 9.6 2029.0003 JAN 39.5 23.8 5.5 19.0 14.1 9.1 2029.0837 FEB 38.8 22.8 5.2 18.3 14.1 8.6 2029.1670 MAR 38.1 21.9 4.6 17.3 14.0 8.0 2029.2503 APR 37.7 21.0 3.8 17.4 13.8 7.5 2029.3337 MAY 36.9 20.0 3.6 17.5 13.7 7.6 2029.4170 JUN 35.9 19.2 3.5 17.6 13.7 7.8 2029.5003 JUL 34.7 18.3 3.3 17.5 13.6 8.3 2029.5837 AUG 33.3 17.4 3.2 17.7 13.5 8.6 2029.6670 SEP 31.6 16.5 2.6 18.1 13.4 8.5 2029.7503 OCT 29.7 15.5 2.0 17.9 13.2 8.6 2029.8337 NOV 27.1 14.8 1.6 17.6 12.9 8.5 2029.9170 DEC 24.5 13.8 1.6 17.3 12.6 8.5 2030.0003 JAN 22.1 12.6 1.3 16.3 12.2 8.4 2030.0837 FEB 20.3 11.5 0.9 14.8 11.8 8.4 2030.1670 MAR 19.2 10.5 0.6 13.8 11.4 8.3 2030.2503 APR 18.9 9.7 0.6 13.9 11.0 8.2 2030.3337 MAY 18.5 9.1 0.5 13.6 10.6 8.2 2030.4170 JUN 18.2 8.5 0.4 13.2 10.3 7.9 2030.5003 JUL 16.8 8.0 0.3 12.9 9.9 7.4 2030.5837 AUG 15.9 7.5 0.2 12.6 9.7 7.1 2030.6670 SEP 15.8 7.0 0.1 11.9 9.5 7.3 2030.7503 OCT 15.0 6.5 0.0 11.4 9.4 7.1