Iceland - go in summer or autumn

[problem1234567]

Have decided that I'd like to visit Iceland (say for 4 full days) inspired by some of the stunning scenery on the travel blogs.

I know one of the big things is viewing the Northern Lights though understand this is only possible September onward.
I could not go till the early Oct (not allowed leave from work in the last two weeks of Aug or September).
But I worry it would be just too cold to be comfortable by the time it gets to Oct.

Or is it best to go in July/ or early to mid Aug when it would be much more pleasant temperature wise but zero chance of seeing the NL.

Any experiences of visiting in either of those time periods?

Thanks

Average temp doesn’t seem that cold in October?

Personally I would want to go in the winter. Can’t you just wear appropriate clothing?

I did see N-Lights (in Iceland) in Late August. not great view, though.
Sounds like N-Lights is important to you so September must be.

I went in July - midnight sun etc. It was amazing even without the northern lights. Temperature was around 14 - 18 so pleasant but not overly warm.

If you want best chance for aurora and amazing experience I recommend late January and early February.
Swimming outside in -23 degrees is an incredible experience. Aurora truly awesome. Blizzards and Pingvella in winter fabulous. Wear thermals and waterproofs. Hire a 4x4.

Go in Jan/Feb and wrap up warm. You need to see it in glorious snowy weather

I took my eldest DD one October - it was much colder than the UK and my DD kept asking if we could go to Sunland next time (she was 6). Outside of Reykavik it was especially cold as the landscapes are open to the elements with few trees and houses. I'd go one extreme or the other and either go in Summer or deep winter (with lots of thermals!). I know from an Icelandic friend that even in Summer though there isn't much need to break out the sunscreen!