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Solar flares in December 1999
C-class169
M-class9
X-class0
LargestM5.31999-12-22
Sunspot number123.5NOAA SWPC
Flares per day (C and above)
M/X flares per day
Same month a year earlier
| Month | C | M | X | Largest |
|---|---|---|---|---|
| December 1998 | 194 | 12 | 0 | M8.0 |
| December 1999 | 169 | 9 | 0 | M5.3 |
Top 15 flares
| Date | Begin | Peak | Min | Class | Location | Region |
|---|---|---|---|---|---|---|
| 1999-12-22 | 18:52 | 19:04 | 16 | M5.3 | N24E19 | 8806 |
| 1999-12-28 | 00:39 | 00:48 | 13 | M4.5 | N20W56 | 8806 |
| 1999-12-27 | 11:54 | 12:06 | 15 | M2.0 | N22W42 | 8806 |
| 1999-12-22 | 01:50 | 02:16 | 42 | M1.8 | N10E30 | 8807 |
| 1999-12-18 | 19:09 | 19:12 | 6 | M1.5 | N20E69 | 8806 |
| 1999-12-21 | 17:12 | 17:19 | 10 | M1.1 | N24E34 | 8806 |
| 1999-12-07 | 21:15 | 21:20 | 8 | M1.0 | S13E66 | 8791 |
| 1999-12-17 | 21:35 | 21:41 | 23 | M1.0 | – | – |
| 1999-12-27 | 01:46 | 01:54 | 23 | M1.0 | N24W36 | 8806 |
| 1999-12-18 | 01:21 | 01:29 | 17 | C9.4 | N19E82 | 8806 |
| 1999-12-29 | 09:22 | 09:27 | 9 | C8.8 | N22W66 | 8806 |
| 1999-12-07 | 01:07 | 01:12 | 7 | C8.7 | – | – |
| 1999-12-06 | 07:00 | 07:18 | 34 | C8.4 | N10E43 | 8788 |
| 1999-12-24 | 09:28 | 09:34 | 15 | C8.4 | – | – |
| 1999-12-17 | 00:13 | 00:21 | 11 | C7.0 | – | – |
All times UTC. Until June 2017 classes are NOAA's reports of the time (GOES-15 and earlier included a 0.7 scaling factor); later classes come from calibrated GOES-16/18 data, so the same flare reads about 1.4× larger. Do not compare the two periods directly.
About this page
178 flares of class C or larger in December 1999; by M/X count it ranks 255 of 565 months.