No surprise there in the difference in tire pressure, there is a difference of 30° between the two readings and you can reasonably expect about 1-PSI increase/decrease with every 10-degrees difference in temperature… And I’m not blowing Hot Air… 
If you are using the same size stock tires as recommended for your vehicle, the tag on the Door Jam will be your best source for information. Get yourself a good quality tire pressure gauge and set it to the specs on the door jam.
As has already been noted, temperature matters… Your tire pressure will also go up after your 50-mile commute… The manufacturer establishes the recommended tire pressure based on the "Standard Day – 59°…).
When you adjust the tire pressure, for every 10-degrees above 59°, reduce the pressure by one-pound, for every 10-degrees below 59°, add one extra pound…
But for all intents and purposes, unless you are at the extremes of your local temperature range (20° to 100°), just fill the tires to the recommended pressure