Boise

Idaho Weather in September

Average temperatures, rainfall, sunshine and the best places to visit in Idaho, the United States of America in September.

Thinking about venturing to Idaho, the United States of America this September and curious about the weather conditions to expect? This page holds all the key information you seek, responding to your question:

What to Expect in Idaho in September

Idaho, the United States of America is a region in the United States of America. September in Idaho generally has temperatures that range from pleasant to warm, with precipitation levels ranging from low to moderate.

Temperatures

The average highest temperatures fluctuate between pleasant in Wallace at 20°C (68°F) to warm in Hagerman at 28°C (82°F). Nighttime temperatures generally drop to 8°C (46°F) in Hagerman and 7°C (45°F) in Wallace.

To learn more about the conditions in specific areas of Idaho, the United States of America, check out the map below.

Precipitation

In September, precipitation varies across different areas. From low rainfall in Hagerman with an average of 8.6 mm (0.3 in) to moderate rainfall in Victor with 47 mm (1.9 in).

Average sunshine

Many locations offer abundant sunshine during this month. For instance, Boise enjoys approximately 303 hours of sunlight, ideal for those seeking sunny weather.

Explore Idaho by month

Pick a month to see the average temperature, rainfall and sunshine in Idaho — and find the best time to visit. (based on Boise)

Best Places to Visit in Idaho in September

Click on a destination dot for more details. Toggle the map to compare temperatures or precipitation across Idaho.

perfect weather
pleasant
tolerable
unpleasant
poor

Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).

Popular Destinations in Idaho

What is the weather like in September for some of the most popular destinations in Idaho, the United States of America?

Temperature range in Idaho (September)

Precipitation variation in Idaho (September)

Boise

In September Boise generally has high temperatures with maximum daytime temperatures around 27°C (81°F), minimum nighttime temperatures around 10°C (50°F) and low monthly rainfall. So on average the conditions are perfect that month.

August
September
October
Max temperature
32°C (90°F)
27°C (81°F)
19°C (66°F)
Min temperature
14°C (57°F)
10°C (50°F)
4°C (39°F)
Monthly sun hours
358 hours
303 hours
238 hours
Monthly rainfall
8.3 mm (0.3 in)
13 mm (0.5 in)
28 mm (1.1 in)
Monthly rainy days
4 days
5 days
8 days
Weather conditions

Coeur d'Alene

In September Coeur d'Alene generally has high temperatures with maximum daytime temperatures around 23°C (73°F), minimum nighttime temperatures around 8°C (46°F) and low monthly rainfall. So on average the conditions are perfect that month.

August
September
October
Max temperature
29°C (84°F)
23°C (73°F)
15°C (59°F)
Min temperature
12°C (54°F)
8°C (46°F)
3°C (37°F)
Monthly sun hours
340 hours
272 hours
192 hours
Monthly rainfall
20 mm (0.8 in)
23 mm (0.9 in)
45 mm (1.8 in)
Monthly rainy days
5 days
7 days
12 days
Weather conditions

Idaho Falls

In September Idaho Falls generally has high temperatures with maximum daytime temperatures around 24°C (75°F), minimum nighttime temperatures around 6°C (43°F) and low monthly rainfall. So on average the conditions are perfect that month.

August
September
October
Max temperature
30°C (86°F)
24°C (75°F)
16°C (61°F)
Min temperature
10°C (50°F)
6°C (43°F)
1°C (34°F)
Monthly rainfall
16 mm (0.6 in)
26 mm (1 in)
32 mm (1.3 in)
Monthly rainy days
5 days
5 days
7 days
Weather conditions

Ketchum

In September Ketchum generally has pleasant temperatures with maximum daytime temperatures around 21°C (70°F), minimum nighttime temperatures around 4°C (39°F) and moderate monthly rainfall. So on average the conditions are perfect that month.

August
September
October
Max temperature
26°C (79°F)
21°C (70°F)
13°C (55°F)
Min temperature
8°C (46°F)
4°C (39°F)
-1°C (30°F)
Monthly rainfall
19 mm (0.7 in)
31 mm (1.2 in)
46 mm (1.8 in)
Monthly rainy days
6 days
6 days
10 days
Weather conditions

Pocatello

In September Pocatello generally has high temperatures with maximum daytime temperatures around 25°C (77°F), minimum nighttime temperatures around 8°C (46°F) and moderate monthly rainfall. So on average the conditions are perfect that month.

August
September
October
Max temperature
31°C (88°F)
25°C (77°F)
17°C (63°F)
Min temperature
13°C (55°F)
8°C (46°F)
3°C (37°F)
Monthly rainfall
27 mm (1.1 in)
31 mm (1.2 in)
32 mm (1.3 in)
Monthly rainy days
6 days
6 days
7 days
Weather conditions

Is your destination not in the list? Have a look at all destinations in Idaho, in the United States of America.

Popular cities in September

Day & night temperatures, rainfall and average weather in Idaho in September.

City Weather Day temp Night temp Rainfall
Boise 27°C (81°F) 10°C (50°F) 13 mm (0.5 in)
Coeur d'Alene 23°C (73°F) 8°C (46°F) 23 mm (0.9 in)
Idaho Falls 24°C (75°F) 6°C (43°F) 26 mm (1 in)
Ketchum 21°C (70°F) 4°C (39°F) 31 mm (1.2 in)
Pocatello 25°C (77°F) 8°C (46°F) 31 mm (1.2 in)
Island Park 21°C (70°F) 1°C (34°F) 41 mm (1.6 in)

Idaho weather in September: frequently asked questions

What is the weather like in Idaho, the United States of America in September?

September in Idaho, the United States of America brings perfect weather. In Boise, daytime temperatures are typically around 27°C (81°F) and nighttime lows hover near 10°C (50°F).

What is the average temperature in Idaho, the United States of America in September?

Average temperatures in Idaho, the United States of America during September range from a nighttime low near 10°C (50°F) to a daytime high around 27°C (81°F) in Boise.

Does Idaho, the United States of America get a lot of rain in September?

Not particularly. Boise averages just 13 mm (0.5 in) of rain in September, making it a mostly dry month for Idaho, the United States of America.

Is September a Good Time to Visit Idaho, the United States of America?

We consider September to be one of the best times to travel to Idaho, the United States of America. Typically, the climate in Boise is perfect.

On average, the best time to visit Idaho, the United States of America is in May, June, September and October with generally perfect weather in Boise. On the other hand, the weather in January, July, November and December tend to be poor.

Interested in more climate information?

We have much more information about the climate in Idaho.

Weather and climate has detailed information for every country in the world. Are you going to the United States of America? Get detailed historical weather averages for many cities in the United States of America.

Not sure yet where to go? We now have a tool which recommends destinations that suit your ideal travel conditions. Find out where to go with our weather planner.

Bucket list

Need travel inspiration? Check out our bucket list articles and be inspired.