Preferred time to visit Portugal

I have been in mid to late February and in September. September the weather is better, anymore I suppose it can get into the 80's. February was pleasant, some rain (a few days in 3 weeks), warm enough to sit on the beach, but not swim. February may also coincide with Carnival (Mardi Gras), but it is not widely celebrated with big events, so you can choose to seek out something, or avoid easily. May would also be pleasant, weather wise.

As for crowds, September and late May would be the busiest of the options, January/February much less so...but anymore, the big cities seem to busy year round.

I was in Portugal from mid-May to early June just before Covid. The weather was mild and mostly sunny. I don't remember any rain, not too hot for walking tours (I too dislike hot weather). The only places that were crowded were the Pena Palace in Sintra and Obidos in mid-morning. I believe both of them are always crowded.

Our trip there was in September 2023 and the weather and temperatures were great. Honestly, I’d go whenever I could get a good deal and adjust my activities accordingly.

After living here for almost 11 years, the first two weeks of October is ideal. It’s still warm but not hot, the rains haven’t started and the tourists have decreased. The other advantage of October is that the sea is as warm as it gets during the year - if swimming is something you enjoy. My second favorite would be late May.

January and February are the wettest and coolest months, but the lowest tourist crowds. The sunny days in winter are pretty spectacular, but you could get several or none.

Thank you all for the insight. I'm definitely leaning towards late September/ early October. That would also lessen the chances of winter weather impacts affecting my departing flights from home. How far in advance should I look for hotels? I usually start about 6 months ahead. My budget for hotels in the US is usually about $200-250 per night. So looking for something similar in that range. Lower would be nice of course but I want to be realistic.

Booking six months in advance is pretty ideal to me. You would have a better choice of places. I like booking with places that I can cancel, just in case. The price range you mention should get you lots of nice options.