This index of geomagnetic storm strength is valuable but doesn't seem to be very available except as html pages or more recent but equally absurd wc format.
This repository instead does some rudimentary parsing to be able to query their data.
The unix stack: bash, sed, grep, make, gnu parallel, gnuplot
Modify the scripts, or use the dst.txt file, which has an line for each hour. See some potential recipes in the makefile.
$ cat dst.txt | sort -h | head -n 20
-472
-429
-427
-426
-425
-422
-422
-418
-413
-405
-402
-396
-391
-387
-383
-382
-382
-374
-374
-373
$ grep -r -- "-4[0-9][0-9]" downloads
downloads/195709.html:13 4 35 -1 -54-125-124-177-299 -329-374-427-373-330-287-269-255 -231-200-177-162-152-142-130-120
downloads/195907.html:15 -6 -14 -19 -29 -30 -21 -21 -20 17 -75 -89-119-112-117-128-180 -255-326-391-429-382-336-338-301
downloads/200311.html:20 -4 -6 -5 -7 -15 -26 -32 -34 -17 -38 -68 -58 -49-102-162-171 -229-329-396-413-422-422-405-343
downloads/195802.html:11 -48 -26 -21 -5 -23-114-217-251 -333-402-425-426-373-360-328-309 -293-255-213-213-208-194-191-189
downloads/198903.html:13 -38 -17 -40 -64 -91 -96-128-138 -143 -88-101-231-246-160-183-221 -210-257-257-255-302-382-418-472
downloads/198903.html:14 -583-589-463-386-346-343-252-238 -193-134-126-119-175-156-144-135 -130-122-137-140-115-124-129-114
$ grep -r -- "-3[0-9][0-9]" downloads
downloads/195709.html:13 4 35 -1 -54-125-124-177-299 -329-374-427-373-330-287-269-255 -231-200-177-162-152-142-130-120
downloads/195907.html:15 -6 -14 -19 -29 -30 -21 -21 -20 17 -75 -89-119-112-117-128-180 -255-326-391-429-382-336-338-301
downloads/200311.html:20 -4 -6 -5 -7 -15 -26 -32 -34 -17 -38 -68 -58 -49-102-162-171 -229-329-396-413-422-422-405-343
downloads/195802.html:11 -48 -26 -21 -5 -23-114-217-251 -333-402-425-426-373-360-328-309 -293-255-213-213-208-194-191-189
downloads/198903.html:13 -38 -17 -40 -64 -91 -96-128-138 -143 -88-101-231-246-160-183-221 -210-257-257-255-302-382-418-472
downloads/198903.html:14 -583-589-463-386-346-343-252-238 -193-134-126-119-175-156-144-135 -130-122-137-140-115-124-129-114
$ cat dst.txt | gnuplot -p -e "plot '<cat'"
Contributions are welcome. Maybe an easy next step would be to produce a csv with the day an hour, rather than just a file with datapoints
MIT, see LICENSE.txt