Chiang Mai in July?

Got a coin? Flip it ;-)
Seriously it can be quite rainy or hardly at all, varies day by day. For example last week it rained here in CM almost 4 days straight and this week hardly any at all. During rainy season between Bangkok and CM there can be localised flooding and in the past it has affected train lines temporarily. The big one was in 2011 but that's the exception not the norm. In the unlikely event that transport is affected by flooding in the next few weeks, no one will know about it much in advance. Check back later, but in general it is not worth worrying about. July can be hot and sunny too.

wondering how much the monsoon season disrupted train/buses up to Chiang Mai or if there will likely be flooding there?
Not at all, unless there is a catastrophe, and that could happen any time of year.

Thanks for your replies :) I don't really mind about rain when I'm there as I am taking the risk of going in the cheaper/wetter season, I just wasn't sure how much of a possibility it would be to be stranded there! Sorry if this is slightly off topic but do you guys have any recommendations for hostels/guest houses in Chiang Mai which are good for solo travellers?

#2 it is quite possible that trains could be disrupted but given they are usually late anyway then you might not notice (although to be fair the Northern line has been much better since the repairs)

Being stranded very unlikely but if you are not planing on breaking the journey in Bangkok on the way south do at least allow enough time for delays

I'm thinking of spending a few days in Bangkok in between and visiting Ayutthaya then as well :)

Sure! Although I've never travelled before so I won't really know what I'm doing!

you can get off the train on the way south in Ayutthaya and then continue to BKK

thanks for the tip :) do you know if a ticket from CH to BKK will work for this journey or will I two separate tickets?