3 weeks of travel in Iran in August

Check the report of my trip to Iran in August 2011:
http://www.molon.de/travelogues/Iran/2011/

Doable, but in the hottest hours of the day you should take a rest in a cool place.

BTW, if you are fit, you could climb Mt Damavand which will be snow-free in August.

Your plan is actually vary good. don't miss your travel to north and Chalus road. It'll help to relieve from the heat and see some greenery and maybe trekking. But also Kashan - Isfahan - Meybod - Yazd - Kerman - Shiraz is essential part of experiencing Iran (not sure if Izeh is great since the heat )
some of my friend has launched a site to help tourists. (visitouriran.com) use their help. specially to travel north and finding natural sites in there.

Regards
Pi

Around Azerbaijan is nice this time of the year also. I just came back from Babak and Kaleybar which was beautiful. https://www.sfiran.com/travel/iran-destination-guide/kaleybar-babak-castle
https://www.lonelyplanet.com/iran/kaleybar-babak-castle.

Sari and Chalus isn't so great. Maybe Tehrani's love the mountain road, but the beach and activities are nothing special compared to other parts of the world. But if you were thinking Castle of Assasins, Soltanieh, Takht-e Soleiman, Urmia, Kandovan, Ardabil, Sarein, Rasht, Masouleh. Then there's many things to see along the way. The north west is ideal during summer anyway, however I agree with the others you can't miss Shiraz and Yazd. Just find somewhere comfortable to sleep with aircon. The Trip Adviser recommendations are very useful.
Good luck and have a great trip!

Go more to the north. Sabalan region (Sarein), Chalus region so on. But, as you said you will go anyway from Isfahan to Yazd, you would enjoy stopping by in Varzaneh: http://wikitravel.org/en/Varzaneh

If you are fan of mountain villages, go to Kouhrang, Chehelgard! These places are not touched very much!

I don't think I will be heading north too much this trip unfortunately. Unless you say the rest of Iran is not doable due to the weather and temperatures. Varzaneh looks beautiful indeed! I will add it to my list, thank you! Have you been here yourself? Do you maybe have some tips?

Thank you so much in advance!

Thank you for your advice! There are too many must sees in Iran. I don't think I will be heading as far north as Kaleybar during this particular trip. I was mainly looking forward to the mountain road indeed but if there is nothing 'special' to do on the coast it might be best not to waste my time there this time.

Did you mainly use tripadvisor for your accommodations or perhaps some other useful sites? I am looking into couchsurfing in particular at the moment so I can meet people along the way.

Thank you Mahdi! Izeh was a maybe anyway so perhaps better to just skip it this time. The essentials are what I am looking into mostly now indeed, I hope the temperatures will be manageable..

Well, I would say, definitely south-er than Shiraz is not doable, cities such as Qeshm so on is not bearable I believe. As for Varzaneh, as you asked for some tips, Yes, I have lived a big part of my life in Varzaneh. I could suggest including salt lake, Gavkhuni wetland, sand dune desert. There are basically two guests houses there, Yasna and Chapaker guest house.

You always can spend days in that area! Not connected to central deserts of Iran, it is not that hot! Still, I would say as hot as Isfahan city. So, basically you need to take rest, from 12 until 4 p.m.

Thank you very much Sinasina! You've been very helpful!