First, look up the maximum wind speed for your location. Any flagged flagpole not rated for this wind speed will be removed from the results.
Maximum wind speed is generally between 85 - 170 mph. This is also known as the nominal design wind speed as determined by the ASCE 7-22 Standard. Wind speeds correspond to approximately a 7% probability of exceedance in 50 years (annual exceedance probability = 0.00143, MRI = 700 years).
Next, choose the type of flagpole you're looking for.