ummmmm ..... it's still not Sept. and your high temp is predicted to be over 105 deg every day in the next ten days. (Sheesh!!) That is still not planting weather. I think you just have to be patient for a little while and wait for your weather to break. You only want to soak your seeds 24 hrs or so.
(how did you get to yes you can plant tomatoes and cukes in Sept, to I'm soaking seeds now?
(The schedules give ranges, because the weather isn't the same every year, so you can't just plant by the calendar)