GFZ definitive record · 3-hour UTC intervals · 1932 → 2026-10-13
September January February March April May June July August September October November December 1938 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 this month's page → Storm nights
7
Time at storm level
11.3%
intervals at Kp ≥ 5−
M T W T F S S
1 2 3 4 5 6 7 8 9 10 11 12 13 G1 14 G2 15 G3 16 17 18 19 20 21 22 23 24 25 26 G1 27 G3 28 G4 29 30 G3
Tap a day — its eight intervals open here.
Highlights
1938 · the year at a glance — storm nights by month · year peak Kp 9.0
number = storm nights
All-time record: Kp 9.0 — reached on 27 days, most recently 2024-05-11.
The hall of storms — the ten greatest since 1932
01 Kp 9.0 The Halloween storms↑ open in the calendar 29–30 Oct 2003 · peak 06:00 UTC · 9.0 ×3
Europe & North America — aurora to the Mediterranean and Florida; Malmö lost power
this storm’s page → 02 Kp 9.0 The Gannon storm↑ open in the calendar 10–11 May 2024 · peak 00:00 UTC · 9.0 ×2
worldwide — aurora photographed on every continent, the strongest storm in two decades
this storm’s page → 03 Kp 9.0 04 Kp 9.0 The Quebec blackout storm↑ open in the calendar 13–14 Mar 1989 · peak 21:00 UTC · 9.0 ×2
North America — Hydro-Québec's grid collapsed in 90 seconds, six million in the dark; aurora to Florida and Cuba
this storm’s page → 05 Kp 9.0 The Easter Sunday storm↑ open in the calendar 24–25 Mar 1940 · peak 15:00 UTC · 9.0 ×2
North America — telegraph and power disturbances across the US
this storm’s page → 06 Kp 9.0 The near-war storm↑ open in the calendar 25–26 May 1967 · peak 21:00 UTC · 9.0 ×2
North America — jammed US early-warning radars, briefly read as an attack
this storm’s page → 07 Kp 9.0 13–14 Jul 1982↑ open in the calendar peak 21:00 UTC · 9.0 ×2
Europe — Swedish railway signalling disrupted
this storm’s page → 08 Kp 9.0 18–19 Sep 1941↑ open in the calendar peak 03:00 UTC
North America & Europe — aurora over wartime blackouts
this storm’s page → 09 Kp 9.0 10 Kp 9.0 Ranked from the data: peak Kp, then intervals spent at 9.0. Nicknames and reach notes only where documented.
Solar Cycle 25 beside the last three maxima → The latest archived week — Kp day by day → The book's frames and that hour's Kp → Kp data: GFZ German Research Centre for Geosciences · CC BY 4.0 ↗