> Thanks Jinx. I don't really need it to be too accurate

Hehe, don't fret. Inaccurate is the easy bit ;-)

> This is really just a learning activity for me. I've been on
> winter break, but a new semester begins Tuesday, so I've
> been learning as much PIC stuff as possible over break

That's good to have a project and have to write the code to
make it work

As I mentioned, WDT is temperature-sensitive, because the
timing component is a resistor, the same as IntRC. The problem
with it as a time-base is that it's a "nominal" value, but without
knowing the temperature you can't say for sure how close to
"nominal" it is. If you want another project, try a thermometer.
WDT is pretty linear. The figures here (as measured with a
100us TMR1 interrupt) are

Temp (degC), WDT period, % of expected

82  2.9716  100.00      80  2.9573   99.99
78  2.9332   99.96      76  2.9050  100.08
74  2.8769  100.19      72  2.8489  100.31
70  2.8201  100.45      68  2.8081   99.99
66  2.7818  100.05      64  2.7624   99.86
62  2.7382   99.84      60  2.7210   99.56
58  2.6830  100.04      56  2.6635   99.84
54  2.6436   99.65      52  2.6232   99.48
50  2.5922   99.71      48  2.5618   99.93
46  2.5346   99.98      44  2.5103  100.12
42  2.4942   99.65      40  2.4675   99.72
38  2.4395   99.85      36  2.4136   99.89
34  2.3882   99.70      32  2.3522  100.39
30  2.3324  100.18      28  2.3029  100.38
26  2.2767  100.45      24  2.2562  100.26
22  2.2356  100.08      20  2.2125  100.00
18  2.1902   99.89      16  2.1592  100.17
14  2.1432  100.24      12  2.1133  100.00
10  2.0846   99.82       5  2.0311  100.77
 0  1.9601   99.86      -3  1.9284  100.04
-7  1.8809  100.12     -10  1.8581  100.34
-13 1.8067  100.13     -15  1.7782  100.00

That will combine WDT, timer, table, and output to a
display. Maybe a bit of maths too

Crystal-based oscillators are more stable but they too
will drift if not compensated. You may get lucky and
set the frequency for what turns out to be a long-term
average, but the chances are you won't

It's an interesting exercise for you though, good luck
and happy PIC'ing

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