Was wondering what month would be the most pleasant weather wise in Spain/Portugal as one considered destination, Vienna/Budapest as an alternative. Ideally not a lot of rain(but hard to predict of course) and temperatures 15-25 degrees.
Weather questions are the hardest to answer because no one can really predict what a particular month in a particular year will bring. Go online and check the historical data for the countries you're interested in paying particular attention to the amount of precipitation. People on here can only give you their own anecdotal experience but that's nothing I would depend on.
For example, I was in Vienna and Budapest last July and it was HOT, so I would not recommend those cities in high summer (mid-June to late Aug) to anyone who doesn't want hot weather, although it was also sunny and dry - for a total of 10 days, only one day with some sprinkles in Vienna. Spring and Fall would be better if you want temps between 15-25, but of course those periods also usually bring a greater possibility of rain - not to say you couldn't find plenty of nice dry days.
I'm not familiar with Spain or Portugal personally but for the temps you're looking for I would think Spring or later in the Fall (late Sept-Oct) would be best.
When were you planning to go??
Vienna, Budapest in order of my preference of favorite times of year to visit
- September 15 to October 15
- October 15 to October 31
- May 15 to June 1
- March 15 to April 30
December 15 to January 2 is also great if you want a Christmas and snow experience. Great time for cultural events as well. Worst times are June, July, August For All Sorts Of Reasons
Spain - the center and south are great in spring and fall, but avoid Easter time (maybe a week or more before to a week after) unless you specifically want to see the Easter processions and religious festivals. Prices go up and it's super crowded. I'd vote for late September to October. Summer is extremely hot. Winter will be cool, and more things will be closed. So April/early May (but not Easter) or fall would get my vote for Spain and southern Portugal. I have not been north of Lisbon, or in the NW of Spain, so these may be different.
I generally favor shoulder seasons to avoid crowds and take advantage of better flight and lodging prices.
Spain can be really cold in the winter in the northern mountain areas - most people don't realize that. Spain, especially south, gets really hot in the summer. With that in mind, I'd want to visit the south in April or October (May or September if you're hoping for beach weather). Northern Spain may be better for May or September. If you want to visit the areas along the northern coast of Spain (San Sebastian, Bilbao, etc.), it's best seen in July and August; outside of high summer months, it's likely to be rainy and chilly.
I loved Spain in April because Holy Thursday in Zaragosa and April Fair in Seville were outstanding cultural experiences. We weren't lucky, we were there in April 2012 and the cold winter hadn't quite let go - so it was very chilly almost the whole trip.
Vienna/Budapest are great in September. The weather is still nice, generally comfortable warm days and cool evenings (all in your 15-25 range), and there are lots of harvest festivals that time of year. Anywhere from May on will be decent if you can't make it in September.