Some diagnostic questions for you:

1) Assuming you located the hole(s) in the tube, are they on the tire or rim side?

2) Do you pump up your tires to the recommended minimum pressure?

3) Did you inspect the tire to see if there is a thorn/nail/staple in the tire that is causing the repeated flats?

4) How many holes in the tube per flat? (Look close, often two holes can me a few mm apart, referred to as a snakebite) .

5) Are goat heads or other thorny plants ubiquitous to the area? (LBS or other local riders would know).

6) To help future diagnostics, you might want to index the rim's valve stem hole to a fixed feature on the tire, like the center of the tire's label. Then, in the future, you notice a pattern like "the flat is always at the 3:00 position", and item #3 may apply.