Trying to decide about what time of year to go to Poland in ‘27.

We went on this tour in early to mid June and the weather was great. I had kept an eye on the weather in Gdansk Warsaw and Krakow to see when I wanted to go. Weather can be so unpredictable of course, but I think going too early in spring you would be at risk of some pretty cold temperatures, especially in Gdansk. If you want to go early or late I would lean toward late (Fall) but that’s just my opinion. I felt that the RS Poland tour was exceptional. Everything about it was great. We went to the WWII museum on our own before the tour started. Fantastic. We stayed 2 extra nights in Krakow and went to Auschwitz, the salt mine, and also did go to see the Lady with an Ermine!

One other thing to add is that I never felt that things were overrun with tourists in Poland. Any crowds were because school kids take field trips to historic and cultural sites in June. Lots of kids!

I'd go in May or September. And no it's nowhere near as busy as Paris or Rome. I'd look at day length when you're considering when to go, too.

I'm actually headed to Poland in early September this year (solo trip, not with a tour group). I picked the date because it worked well with my work schedule, my child school schedule and childcare, and because I read it's good weather-wise. Most European kids would have just started school so I don't anticipate many field trips during first week of school year.
The focus for my trip is WWII as well, and I'll be doing a full day study guide tour at Auschwitz. This will be my first trip to Poland. I was going to Gdansk initially before Krakow, but had to rearrange travel schedule because of other cities I added.

From Krakow I'll fly to Budapest (first time there) for a few days, then fly to Amsterdam for a day layover before flying back to the US. I've been to Amsterdam before but never to Ann Frank's house, so that's my priority (and I have scheduled on my calendar to log on when tickets become available for my day there).
I've been to Vienna and Paris, and would vote for Vienna if you are looking for another city nearby. Prague is also a fantastic city.

I've booked Krakow for the third week of September this year. I debated between September and October and looked through historical weather for the past few years on timeanddate.com. Obviously it's not an exact science, but as pbscd mentioned, there's more daylight hours in September.

We went on the last RS Poland tour in fall of 2025. The weather was fine. We wore fall jackets and/ or a light puffy.

The RS Poland Tour was absolutely fantastic. Highly recommend.

No advice on the time of year question, other than to confirm that your bucket list item is well worth the trip. I had the massive good fortune to see "Lady with an Ermine" in 2012 not too long after it had been partially restored and was on solo display. A tourmate and I got to the museum when it opened and we had her and the room all to ourselves (and the security guy, of course). She is stunning in person and I was definitely overcome (and I don't generally do that). Like the Mona Lisa, she's smaller than you expect but just as beautiful as you could ever hope.

If you have not watched the documentary "Rape of Europa" or read the book Monuments Men by Robert Edsel, both are worth a look. She's one of the rescued paintings.