Sentence:  By early <WSD>summer</WSD> , he wrote from Laramie that he was suffering from the wound inflicted in the ambush and was in a bad way financially , so Pels sent him a draft for $ 100 , warning that it was still not wise for him to return . 
Meaning of the word marked with <WSD> tags:  the warmest season of the year; in the northern hemisphere it extends from the summer solstice to the autumnal equinox