Asphalt shingles resist wind uplift by small deposits of asphalt between the courses that seal each shingle to the one below it. The deposits have to get hot enough to soften and adhere to the lower shingle therefore in a high wind area it is wise to shingle a roof in warm weather.

What wind loads are your shingles rated for? Are they 30 yr, 40 yr, or lifetime? Some of the 40 and lifetime shingles can be installed to withstand up to 130 mph winds, although the guarantees are limited (ours are guaranteed for 10 years).

I would think that it would be too costly to redo the roof at this point. I would wait and see how the shingles hold up through the summer. Replacing the asphalt with a higher grade asphalt would probably run you $150-$200 per square. Metal would be somewhere around $300/sq and I hear that the metal that looks like shingle is even higher.

They are 30 year AR rated for wind resistance to 110 mph.

Back in the old asphalt 3-tab shingle days in the winter here in the mojave desert, we put dabs of henrys roof cement out of a caulking tube to get the shingles to stick as it was too cold for the seal tabs to adhere as mentioned above.

I doubt any roofer would be willing to do that theses days unless you open your wallet, but you might consider doing it diy in order to keep the remainig shingles on your roof as well as replacing the missing.