Sun · flares

A Sun that bursts

Flares are sudden releases of magnetic energy above active regions. The flashes in this view recall the classes of the strongest flares in the GOES catalogue (X, M); their positions are illustrative.

Latest catalogued flare

B7.5

2026-10-24 02:11 UTC

Strongest in the catalogue

X28

2003-11-04

X-class flares

558

1975 → 2026

GOES X-ray flare lists (NOAA SWPC/NGDC events, yearly compilations by NASA GSFC) · U.S. Government work, public domain (NOAA/NASA) · 10/24/26

Illustrative rendering: procedural prominence loops and flashes; classes from the GOES catalogue below.

Catalogued flares

94,033

1975 → 2026-10-24

GOES X-ray flare lists (NOAA SWPC/NGDC events, yearly compilations by NASA GSFC) · U.S. Government work, public domain (NOAA/NASA) · 10/24/26

X-class flares

558

7954 M-class

GOES X-ray flare lists (NOAA SWPC/NGDC events, yearly compilations by NASA GSFC) · U.S. Government work, public domain (NOAA/NASA) · 10/24/26

Latest catalogued flare

B7.5

2026-10-24 02:11 UTC · AR 14560

GOES X-ray flare lists (NOAA SWPC/NGDC events, yearly compilations by NASA GSFC) · U.S. Government work, public domain (NOAA/NASA) · 10/24/26

Strongest in the catalogue

X28

2003-11-04 18:29 UTC · S19W83

GOES X-ray flare lists (NOAA SWPC/NGDC events, yearly compilations by NASA GSFC) · U.S. Government work, public domain (NOAA/NASA) · 10/24/26

X- and M-class flares per year GOES X-ray flare lists (NOAA SWPC/NGDC events, yearly compilations by NASA GSFC) · U.S. Government work, public domain (NOAA/NASA) · 10/24/26 GOES X-ray flare lists (NOAA SWPC/NGDC events, yearly compilations by NASA GSFC) · U.S. Government work, public domain (NOAA/NASA) · 10/24/26

Show the data as a table

Number of flares per calendar year in the GOES catalogue (NOAA). The current year is provisional; 2020 is marked “instrument change”: since December 2019 the flux is no longer reduced by the 0.7 factor, which raises classes by about 40%.

C-class flares per year GOES X-ray flare lists (NOAA SWPC/NGDC events, yearly compilations by NASA GSFC) · U.S. Government work, public domain (NOAA/NASA) · 10/24/26

Show the data as a table

Detection of C-class flares depends on the background level, hence on the cycle phase and the instrument; these counts are less homogeneous than those of M and X classes.

Ten strongest flares (peak flux derived from the class)

#	Class	Start (UTC)	Peak	Peak flux (W/m²)	Position	Active region
1	X28	2003-11-04 18:29	18:50	3E-3	S19W83	10486
2	X20	1989-08-15 23:08	23:17	2E-3	S18W84	5629
3	X20	2001-04-02 19:32	19:51	2E-3	—	—
4	X17	2003-10-28 08:51	10:10	2E-3	—	10486
5	X17	2005-09-07 15:17	15:40	2E-3	S11E77	10808
6	X15	1989-03-06 12:54	13:10	2E-3	N35E69	5395
7	X14	2001-04-15 11:19	11:50	1E-3	S20W85	9415
8	X13	1984-04-24 21:56	22:01	1E-3	S12E43	4474
9	X13	1989-10-19 11:29	11:55	1E-3	S27E10	5747
10	X12	1982-06-06 14:30	14:54	1E-3	S09E25	3763

The peak flux (0.1–0.8 nm, W/m²) is derived from the published class, e.g. X28 = 28 × 10⁻⁴ W/m²; the GOES detectors saturated above X17 before 2003, so the 4 November 2003 flare is an estimate.

Filterable catalogue GOES X-ray flare lists (NOAA SWPC/NGDC events, yearly compilations by NASA GSFC) · U.S. Government work, public domain (NOAA/NASA) · 10/24/26

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Start (UTC)	Peak	End	Duration	Class	Peak flux (W/m²)	Position	Active region
2021-10-26 00:40	00:47	00:54	14 min	M1.3	1E-5	—	—
2021-10-09 04:19	04:38	04:53	34 min	M1.6	2E-5	N17E09	12882
2021-09-23 02:35	02:42	02:50	15 min	M2.8	3E-5	S27E21	12871
2021-08-28 03:39	04:11	04:23	44 min	M4.7	5E-5	S28W01	12860
2021-07-04 03:01	03:09	03:15	14 min	M1.5	2E-5	N00W00	12838
2021-07-03 14:59	15:03	15:14	15 min	M1	1E-5	N24W82	12838
2021-07-03 12:18	12:29	12:34	16 min	X1.5	2E-4	N24W81	12838
2021-07-03 05:04	05:17	05:22	18 min	M2.7	3E-5	N23W78	12838
2021-05-23 09:00	09:08	09:14	14 min	M1.1	1E-5	—	12824
2021-05-22 19:30	19:36	19:43	13 min	M1.4	1E-5	N19E15	12824
2021-05-22 15:03	15:11	15:16	13 min	M1.1	1E-5	N17E20	12824
2021-05-07 16:43	17:04	17:19	36 min	M3.9	4E-5	N17E78	12822
2021-04-19 21:19	21:42	21:59	40 min	M1.1	1E-5	S24E25	12816
2020-11-29 11:34	12:11	12:41	67 min	M4.4	4E-5	—	—
2020-05-29 05:13	05:24	05:28	15 min	M1.1	1E-5	—	—
2017-10-20 21:10	21:28	21:37	27 min	M1.1	1E-5	—	12685
2017-09-10 13:35	14:06	14:31	56 min	X8.2	8E-4	—	12673
2017-09-09 20:04	21:53	22:41	157 min	M1.1	1E-5	S07W74	12673
2017-09-09 08:50	09:04	09:42	52 min	M3.7	4E-5	—	12673
2017-09-09 02:14	02:28	02:43	29 min	M1.1	1E-5	S13W69	12673
2017-09-08 21:33	21:45	21:56	23 min	M2.1	2E-5	—	12673
2017-09-08 13:09	13:47	14:04	55 min	M2.9	3E-5	S08W68	12673
2017-09-08 05:40	05:49	05:58	18 min	M8.1	8E-5	S10W57	12673
2017-09-08 01:39	01:43	01:45	6 min	M1.2	1E-5	S06W55	12673
2017-09-08 00:19	00:24	00:29	10 min	M1.3	1E-5	S09W54	12673
2017-09-07 21:50	21:59	22:14	24 min	M3.9	4E-5	—	12673
2017-09-07 12:20	12:36	12:55	35 min	X1.3	1E-4	S11W49	12673
2017-09-07 08:11	08:15	08:18	7 min	M7.3	7E-5	—	12673
2017-09-07 07:49	07:54	07:58	9 min	M1.4	1E-5	—	12673
2017-09-07 02:59	03:02	03:08	9 min	M2.4	2E-5	—	12673
2017-09-06 21:33	21:39	21:44	11 min	M1.2	1E-5	—	—
2017-09-06 17:21	17:30	17:35	14 min	M1.4	1E-5	—	12673
2017-09-06 13:51	13:56	14:03	12 min	M2.5	2E-5	S09W38	12673
2017-09-06 09:53	10:02	10:10	17 min	X9.3	9E-4	S08W33	12673
2017-09-06 06:57	07:10	07:17	20 min	X2.2	2E-4	S07W33	12673
2017-09-05 15:37	15:43	15:51	14 min	M2.3	2E-5	S09W24	12673
2017-09-05 04:33	04:40	04:43	10 min	M3.8	4E-5	—	12673
2017-09-05 02:33	02:53	03:07	34 min	M3.2	3E-5	—	12673
2017-09-05 01:42	01:51	02:04	22 min	M1	1E-5	—	12673
2017-09-04 23:03	23:08	23:11	8 min	M4.2	4E-5	—	12673
2017-09-04 20:10	20:14	20:19	9 min	M2.1	2E-5	—	12673
2017-09-04 18:28	18:33	18:37	9 min	M5.5	6E-5	S11W16	12673
2017-09-04 17:59	18:02	18:06	7 min	M1.5	2E-5	—	12673
2017-09-04 16:46	17:37	17:52	66 min	M1.7	2E-5	—	12673
2017-09-04 16:05	16:22	16:31	26 min	M1	1E-5	—	12673
2017-09-04 13:11	13:30	13:33	22 min	M1.5	2E-5	S06W13	12673
2017-09-04 03:36	03:49	04:05	29 min	M1.2	1E-5	S10W04	12673
2017-08-19 23:36	23:52	00:03	27 min	M1.1	1E-5	—	12672
2017-07-13 23:07	00:09	01:24	137 min	M2.4	2E-5	S06W29	12665
2017-07-09 01:09	01:18	01:37	28 min	M1.3	1E-5	S08E37	12665

Method and sources

The catalogue reproduces the NOAA (SWPC/NGDC) GOES event lists compiled yearly by the NASA GSFC Hesperia centre: start, peak and end (UT), class, heliographic position and active region when known. The class encodes the peak flux in the 0.1–0.8 nm band: C = 10⁻⁶ W/m², M = 10⁻⁵, X = 10⁻⁴, times the number (M2.3 = 2.3 × 10⁻⁵ W/m²).

Lines without an X-ray class (optical or sub-threshold events) are not imported. The last two years are re-read on each import; duplicates are rejected by start time and class. Yearly counts are computed from the imported catalogue.

Reading these data

Until December 2019 NOAA applied a 0.7 factor to the XRS-B flux of GOES 8 to 15; since GOES-16 became the primary satellite the raw flux is used. For the same physical flux, a class after 2020 is therefore about 1.4 times higher (Janssens et al., 2025). Counts before and after 2020 are not directly comparable.

SOURCES OF THIS PAGE

GOES X-ray flare lists (NOAA SWPC/NGDC events, yearly compilations by NASA GSFC): NOAA SWPC/NGDC GOES X-ray flare event lists (1975–), yearly compilations by K. Tolbert, NASA GSFC Hesperia. Flare classes as reported by NOAA at the time: until December 2019 the XRS-B flux carried a 0.7 scaling factor (Janssens et al., 2025). · source page ↗
Licence : U.S. Government work, public domain (NOAA/NASA) · retrieved on Oct 24, 2026 · SHA-256 775bfeb19587…
Janssens (2025): Janssens, J., et al. (2025). Solar flare rates and probabilities based on the McIntosh classification: impacts of GOES/XRS rescaling and recalibration. Journal of Space Weather and Space Climate. · doi:10.1051/swsc/2025007
Licence : Published literature; cited

Solar flares GOES X-ray flare catalogue since 1975

A Sun that bursts