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.
Most / Least Educated Cities in DC. The average temperature of Washington is 54.72Â°F, which is about the same as the District of Columbia average temperature of 54.73Â°F and is about the same as the national average temperature of 54.45Â°F.