The 2 largest cities in Idaho are Boise with a population of  145,987 and Nampa with 81,557. The next 3 largest cities are  Meridian with 75,092, Idaho Falls with 56,813 and â¦ Pocatello with  54,255.
Averages for Washington DC in September. The weather in September in Washington DC is very attractive for those that want to avoid the peak heat of summer, yet still enjoy lots of warm days on their visit. On average, peak temperatures during the day in September still reach up to 27Â°C.
On a few of the warmer days you should expect highs reaching up into the mid-90s F (34-35C) or more. On average, about 6-7 days this month will likely reach or exceed 90F (32C). During past Junes the temperature Washington, DC has seen temperature extremes from 47F (8.3C) to 104F (40C). Washington, DC usually sees sunny or at least partly sunny skies on about 18 days this month with rain occurring on about 9 or 10 days with thunderstorms likely on 6 days.