Boise, Idaho Weather
Thunder retreats as the monsoon dies. Day 93 of summer. Read this microseason across nine climate regions →
Boise weather forecast — hour by hour, 7-day outlook, NOAA radar
Conditions updated 8:24 AM MDT · Open-Meteo
- TodaySep 21Clear——86°53°—
- TuesdaySep 22Overcast——86°57°0°
- WednesdaySep 23Overcast——88°59°+2°
- ThursdaySep 24Overcast——93°68°+5°
- FridaySep 25Overcast——80°59°-13°
- SaturdaySep 26Overcast——72°51°-8°
- SundaySep 27Overcast——72°59°0°
Air quality now AQI 17 · Good
AQI 17 (Good), driven by PM2.5. AQI projected to climb to 44 over the next 6 hours.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion during the projected peak around 8 PM.
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).
September dries up ditches or breaks down bridges.
- Moonrise
- 5:31 PM
- Moonset
- 1:58 AM
- In sign
- ♑︎ Capricorn
Thunder retreats as the monsoon dies
Read this microseason across nine climate regions →
All 72 microseasons on the year wheel →
Boise at a glance
- Today vs. normal: Today averages 70°F (high 86°F, low 53°F), 6°F above the 64°F normal for Sep 21
- Last frost: April 24 (1991–2020 median, NOAA station 4 km away)
- Microseason: Sep 21–25
- Planting calendar: September — plant garlic (overwinter); harvest tomatoes, peppers, beans, summer squash, winter squash
16-Day Forecast — Boise
- Mon86°53°1%
- Tue86°57°4%
- Wed88°59°0%
- Thu93°68°1%
- Fri80°59°7%
- Sat72°51°7%
- Sun72°59°2%
- Mon70°53°3%
- Tue71°49°2%
- Wed79°58°3%
- Thu83°63°4%
- Fri77°58°10%
- Sat71°50°13%
- Sun81°57°3%
- Mon71°57°0%
- Tue77°59°3%
Forecast data from Open-Meteo (CC BY 4.0).
Live wind & temperature near Boise
Interactive wind and temperature map centered on Boise — it loads in your browser. Open the full weather map.
Right now in the garden
Fall planting + final harvests
As of September 21, the season's first frost (typically October 21) is approaching. Pick what frost-tender plants still carry before the next cold front. This city's planting calendar for September: plant garlic (overwinter); harvest tomatoes, peppers, beans, summer squash, and winter squash.
SPC Convective Outlook
Storm Prediction Center — Boise
SPC includes Boise in the general thunderstorm area today — no severe risk, but storms are possible.
- TODAYTSTMGeneral Thunderstorms
- TOMORROWTSTMGeneral Thunderstorms
- DAY 3NONENo severe risk
Thunderstorms possible. Not severe, but capable of producing lightning and brief heavy rain.
Source: NOAA / NWS Storm Prediction Center categorical convective outlook.
Sun & seasons in Boise
Boise sits in Ada County, where the year’s longest day runs 15h 26m of daylight and its shortest just 8h 56m — a swing of +6h 30m between the June and December solstices. Clocks spring forward on Sunday, March 8, 2026 and fall back on Sunday, November 1, 2026.
Boise is the state’s largest city. The nearest town Boise tracks is Meridian, roughly 8 miles to the W.
Air quality in Boise
Air quality in Boise’s county has trended cleaner since 2020; its cleanest year on record was 2025 (median AQI 42). See the full air-quality history for Boise.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| April | lettuce, peas, spinach, radishes | radishes |
| May | lettuce, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, spinach, radishes |
| June | tomatoes, peppers, beans, squash | lettuce, peas, spinach, radishes |
| July | tomatoes, peppers, beans, squash | lettuce, peas, spinach, beans, summer squash, garlic |
| August | beans, squash, fall brassicas, carrots | tomatoes, peppers, beans, summer squash, winter squash |
| September | garlic (overwinter) | tomatoes, peppers, beans, summer squash, winter squash |
| October | garlic (overwinter) | tomatoes, peppers, beans, summer squash, winter squash, fall brassicas, carrots |
| November | — | fall brassicas, carrots |
A year in weather
Boise's warmest month is July (~77°F mean) and its coldest is December (~32°F). Rainfall peaks in December (1.5 inches) and bottoms out in August (0.2 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 32° | 1.4″ | 5 |
| February | 38° | 1.0″ | 4 |
| March | 45° | 1.3″ | 5 |
| April | 51° | 1.2″ | 4 |
| May | 60° | 1.4″ | 4 |
| June | 68° | 0.8″ | 2 |
| July | 77° | 0.2″ | 1 |
| August | 76° | 0.2″ | 0 |
| September | 66° | 0.4″ | 1 |
| October | 53° | 0.8″ | 2 |
| November | 40° | 1.2″ | 4 |
| December | 32° | 1.5″ | 5 |
Regional context
Similar climates Garden City, ID, Hidden Springs, ID, Meridian, ID
Per NOAA NCEI 1991-2020 normals, Boise runs from a 32°F January mean to 77°F in July, a 45°F seasonal spread, with near 11.5 inches of precipitation across about 38 wet days.
Boise's moisture rides winter storm tracks: December brings 1.5 inches over 4.8 wet days, while August sees only 0.2 inches across 0.4 days in the dry warm season. It is a winter-storm rhythm Boise shares with places like Garden City, ID, Hidden Springs, ID and Meridian, ID.
Once Boise passes April 24, freezes fade and Boise's beds take peas, lettuce, spinach, and radishes. Tomatoes and peppers do best set out two weeks later in Boise, once nights clear the mid-40s°F. By October 21, frost is back in Boise — protect or harvest anything tender. Open lawns in Boise whiten first when frost returns.
Similar climates: Garden City, ID, Hidden Springs, ID, Meridian, ID, Kuna, ID, Eagle, ID.
Frequently asked
- When does it freeze in Boise?
- In Boise, expect the last spring frost near April 24; Boise's first autumn frost comes around October 21.
- What is the rainy season in Boise?
- December is the wettest month in Boise, about 1.5 inches on average; the year totals roughly 12 inches.
- What is the warmest month in Boise?
- Boise peaks in July, when the mean runs near 77°F.
- What is the coldest month in Boise?
- December is Boise's coldest month, averaging about 32°F.
- When can I start a vegetable garden in Boise?
- Around April 24, start frost-hardy crops in Boise; tomatoes and basil belong a fortnight later.
- How many rainy days does Boise get?
- Expect roughly 38 wet days a year in Boise.
- What hardiness zone is Boise?
- With December around 32°F, Boise's zone reflects that minimum — the USDA ZIP map confirms Boise's band.
- What is the 10-day forecast for Boise?
- Boise's extended outlook — daily high and low temperatures and precipitation chances for each upcoming day — is in the daily forecast above.
- Will it rain this week in Boise?
- See this week's day-by-day rain chances for Boise in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Boise?
- Current conditions for Boise and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Boise forecast updated?
- The Boise forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Boise?
- Today's sunrise and sunset times for Boise are in the Almanac section above, along with civil dawn, civil dusk, and day length. Day length is longest near the summer solstice and shortest near the winter solstice.
- How accurate is the weather forecast for Boise?
- The next few days in Boise's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Boise sits at 43.6°N; its climate zone is warm-summer Mediterranean (Köppen approximation).
ZIP codes in Boise
- 83701
- 83702
- 83703
- 83704
- 83705
- 83706
- 83708
- 83709
- 83712
- 83713
- 83715
- 83716
- 83717
- 83720
- 83722
- 83724
- 83725
- 83728
- 83729
- 83735
- 83756
- 83799