Is it o.k. to keep my betas tank water temperature at 70 degrees?

This is the temperature that my non heated 3 gallon tank has adjusted to over a weeks time period. Between 69.2 and 70.2 is the temperature fluctuation difference . I am using a digital water thermometer to know it's exact temp. It suctions on the side and you drop in the meter part n cord into the tank trying to get a center of the tank water reading. Thanks for your advice,answer and help. Tom