Meridian, Idaho Weather
Summer heat breaks with monsoon. Day 43 of summer. Read this microseason across nine climate regions →
Meridian weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayAug 2Mostly Clear——86°61°—
- MondayAug 3Clear——82°54°-4°
- TuesdayAug 4Overcast——93°54°+11°
- WednesdayAug 5Overcast——98°59°+5°
- ThursdayAug 6Clear——106°67°+8°
- FridayAug 7Clear——108°72°+2°
- SaturdayAug 8Clear——102°66°-6°
AQI 139 (Unhealthy for Sensitive Groups), driven by PM2.5. AQI down 17 over the last 6 hours — air quality is improving sharply. PM2.5 at 49.6 µg/m³, PM10 at 51.9 µg/m³ — typical background levels with no transport signature.
CAUTION Sensitive groups (children, elderly, respiratory conditions) should limit prolonged outdoor exertion, especially during the projected peak around 5 PM.
What's driving it
Ozone × UV × Sky
Ozone at AQI 43 now. With UV 1.7 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 10.
- Present
- AQI 43
- UV peak
- 1.7 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 10
PM × Wind × Precip
PM2.5 at 49.6 µg/m³, PM10 at 51.9 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.96
- Wind
- light
- Recent rain
- 0h in last 6h
- Pattern
- background
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).








































Red sky at night, sailor's delight.
- Moonrise
- 10:32 PM
- Moonset
- 10:57 AM
- In sign
- ♓︎ Pisces
Summer heat breaks with monsoon
Meridian at a glance
- Today vs. normal: 5°F above the seasonal normal for this latitude
- Last frost: May 8 (climatological average for this latitude)
- Microseason: Aug 1–5
- Planting window: Sow fall peas. Start kale and collard seedlings for fall.
ZIP codes: 83642, 83646
16-Day Forecast — Meridian
- Sun86°61°0%
- Mon82°54°0%
- Tue93°54°0%
- Wed98°59°0%
- Thu106°67°0%
- Fri108°72°0%
- Sat102°66°0%
- Sun101°64°1%
- Mon99°63°1%
- Tue102°60°2%
- Wed101°64°0%
- Thu94°64°3%
- Fri94°58°6%
- Sat101°68°9%
- Sun101°66°17%
- Mon98°61°15%
Forecast data from Open-Meteo (CC BY 4.0).
Live wind & temperature near Meridian
Right now in the garden
Peak growing season
As of August 2, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.
Sun & seasons in Meridian
Meridian 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, the state’s largest city, lies about 8 miles to the E. The nearest town Meridian tracks is Boise, roughly 8 miles to the E.
Air quality in Meridian’s county has trended cleaner since 2020; its cleanest year on record was 2025 (median AQI 42). See the full air-quality history for Meridian.
Microseason · August 1–5
Summer heat breaks with monsoon
Late summer monsoon surge; southern reaches drench under Gulf moisture; northern peaks cool rapidly as monsoon remnants push north.
Day 214 of 365 · Wedge 43 of 72
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | — | — |
| February | — | — |
| March | — | — |
| April | — | — |
| May | lettuce, peas, spinach, radishes | lettuce, peas, radishes |
| June | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | tomatoes, peppers, beans, squash | tomatoes, beans, summer squash |
| August | tomatoes, peppers, beans, squash, fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| September | fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| October | — | winter squash, tomatoes (last) |
| November | — | — |
| December | — | — |
A year in weather
The year in Meridian tops out in July (~75°F) and dips lowest in January (~31°F), with December wettest at 1.4 inches and August driest at 0.2 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 31° | 1.4″ | 5 |
| February | 37° | 1.0″ | 4 |
| March | 45° | 1.3″ | 4 |
| April | 50° | 1.1″ | 4 |
| May | 59° | 1.4″ | 4 |
| June | 67° | 0.7″ | 2 |
| July | 75° | 0.3″ | 1 |
| August | 74° | 0.2″ | 1 |
| September | 64° | 0.4″ | 1 |
| October | 52° | 0.8″ | 3 |
| November | 40° | 1.2″ | 4 |
| December | 31° | 1.4″ | 5 |
Regional context
Drawing on NOAA NCEI 1991-2020 normals, Meridian's January averages 31°F and July 75°F — 44°F apart — while precipitation totals roughly 11 inches over some 37 days.
Precipitation in Meridian peaks in the cool season: December averages 1.4 inches across 4.7 storm-fed days, while August bottoms out at 0.2 inches over just 0.7 rainy days. It is a winter-storm rhythm Meridian shares with places like Garden City, ID, Eagle, ID and Star, ID.
The cool-season window in Meridian starts at late-May, when nights stop freezing — think peas, lettuce, spinach, and radishes. In Meridian, warm-season transplants — tomatoes, peppers, basil — wait two weeks past Meridian's frost date. Around early-October, freezing nights resume in Meridian and tender crops must come in. In Meridian, low spots run 4-7°F colder than nearby slopes, nudging Meridian's frost dates a week.
Similar climates: Garden City, ID, Eagle, ID, Star, ID, Boise, ID, Nampa, ID.
Naturalist notes
By late May, western tanagers return to the cottonwood corridors along the Boise River, their breeding song carrying through the lengthening evenings.
Common lilac leaf-out is well underway by mid-May, a phenological marker that often aligns with the last spring frost in this part of the Treasure Valley.
Frequently asked
- When does it freeze in Meridian?
- In Meridian, expect the last spring frost near mid-May; Meridian's first autumn frost comes around mid-October.
- What is the rainy season in Meridian?
- Meridian sees its heaviest rain in December (around 1.4 inches), part of roughly 11 inches a year.
- What is the warmest month in Meridian?
- July is Meridian's warmest month, averaging about 75°F.
- What is the coldest month in Meridian?
- Meridian bottoms out in January, with a mean near 31°F.
- When can I start a vegetable garden in Meridian?
- Meridian's last frost (mid-May) cues hardy greens; in Meridian, hold heat-lovers two weeks past.
- How many rainy days does Meridian get?
- Meridian records around 37 days of measurable precipitation annually.
- What hardiness zone is Meridian?
- Meridian's USDA zone comes from its January mean (31°F); enter the ZIP on the USDA lookup for the number.
- What is the 10-day forecast for Meridian?
- Meridian'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 Meridian?
- See this week's day-by-day rain chances for Meridian in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Meridian?
- Current conditions for Meridian and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Meridian forecast updated?
- The Meridian forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Meridian?
- Today's sunrise and sunset times for Meridian 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 Meridian?
- The next few days in Meridian's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Climate
Meridian's warm-summer Mediterranean climate in Idaho pairs 31°F Januarys with 75°F Julys, 44°F apart across the seasons.
Across the year, Meridian collects about 11 inches of precipitation over roughly 37 days with measurable rain or snow.
At 43.6°N, Meridian's 44°F summer-to-winter swing sets when Meridian's gardens wake and when frost returns.
ZIP codes in Meridian
- 83646
- 83642
- 83680