Two questions...

Firstly I have a question about Japan and bugs. I know this has been covered on here before and I've been researching the big spiders in Japan but I just wondered if it is the same up in Hokkaido, is the climate cooler there hence less spiders? or is it just the same as the rest of Japan?

Second question is about weather, I've been to Japan twice before in the Spring both times but next time I'd like to go in Autumn but when it's still warm... when is the best time (I'm thinking of staying for a month) to enjoy warm weather without too much humidity or heat but warm enough to just wear short sleeves or thin cardigan? also how early do the autumn leaves come out?

Thanks!

There are no poisonous spiders in Japan. And they are not numerous except in autumn (but they stick to their nets in the bushes). So, Japan is generally a comfortable destination for people who do not like spiders.

Second question is about weather, I've been to Japan twice before in the Spring both times but next time I'd like to go in Autumn but when it's still warm... when is the best time

The month of October is very comfortable in most of Japan:
http://www.japan-guide.com/e/e2273.html

also how early do the autumn leaves come out?

It is explained here (as a rule of thumb, you will need a jacket by the time the autumn leaves come out):
http://www.japan-guide.com/e/e2014_when.html

As Uji-san says there are no poisonous spiders in Japan. I have visited the Kiso valley in October & there were many spiders in the trees & bushes but they stay on their webs out of the way and do not come into buildings. As for the weather October is lovely but the temperature will vary depending on where you are. For instance Hiroshima was still very Hot & humid while Magome & Tokyo were comfortably warm when I was there.

Thanks. It wasn't the poison I was really thinking about... I have a very serious phobia of spiders of any size so I just wondered if they were smaller up north.

Also... is there a particular time they would be found inside? just the summer? I might stay with someone for a while but I'm scared they'll be inside.