Unless you're using a fairly old version of MATLAB, I recommend using readtable and datetimes. It might go something like this:
>> t = readtable('Climatology.xls');
In the version I'm using, DATE came in as a datetime automatically. You may have to tell readtable to do that, using detectimportoptions, or you may have to convert from text to datetime by hand after reading. Still I think you'll be happier. You will need to fix the two-digit issue (which is the file, not really readtable's fault -- although you could probably specify a format using detectimportoptions), and then split DATE into components:
>> t.DATE = t.DATE + calyears(100);
>> [t.YEAR,t.MONTH,t.DAY] = ymd(t.DATE);
>> t = t(:,{'STATION' 'NAME' 'LATITUDE' 'LONGITUDE' 'ELEVATION' 'DATE' 'YEAR' 'MONTH' 'DAY' 'PRCP' 'SNOW' 'TAVG'});
Also recommended to use categorical for repeated text:
>> t.STATION = categorical(t.STATION);
>> t.NAME = categorical(t.NAME);
>> head(t)
ans =
8×12 table
STATION NAME LATITUDE LONGITUDE ELEVATION DATE YEAR MONTH DAY PRCP SNOW TAVG
___________ _______________ ________ _________ _________ ___________ ____ _____ ___ ____ ____ ____
USC00291469 CARLSBAD, NM US 32.348 -104.22 951 01-Jan-2010 2010 1 1 2.4 5 8
USC00291469 CARLSBAD, NM US 32.348 -104.22 951 01-Feb-2010 2010 2 1 0 0 8.7
USC00291469 CARLSBAD, NM US 32.348 -104.22 951 01-Mar-2010 2010 3 1 1 0 16.3
USC00291469 CARLSBAD, NM US 32.348 -104.22 951 01-Apr-2010 2010 4 1 3 0 18
USC00291469 CARLSBAD, NM US 32.348 -104.22 951 01-May-2010 2010 5 1 5.1 0 22.4
USC00291469 CARLSBAD, NM US 32.348 -104.22 951 01-Jun-2010 2010 6 1 999 0 999
USC00291469 CARLSBAD, NM US 32.348 -104.22 951 01-Jul-2010 2010 7 1 23.1 0 28.9
USC00291469 CARLSBAD, NM US 32.348 -104.22 951 01-Aug-2010 2010 8 1 39.4 0 28.5
