Meridian, Idaho Weather
Pikas hayfeeding in granite peaks. Day 77 of spring. Read this microseason across nine climate regions →
Meridian weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 4Overcast——80°57°—
- FridayJun 5Overcast——88°51°+8°
- SaturdayJun 6Overcast——72°52°-16°
- SundayJun 7Overcast——70°46°-2°
- MondayJun 8Light Drizzle—0.04″64°57°-6°
- TuesdayJun 9Light Drizzle44%0.04″66°53°+2°
- WednesdayJun 10Light Drizzle28%0.05″54°47°-12°
PM2.5 at 10.5 µg/m³, PM10 at 14.0 µg/m³ — typical background levels with no transport signature. AQI flat over the last 6 hours (within ±3 points).
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
Ozone × UV × Sky
Ozone at AQI 39 now. With UV 5.4 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 28 by mid-afternoon.
- Present
- AQI 39
- UV peak
- 5.4 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 28
PM × Wind × Precip
PM2.5 at 10.5 µg/m³, PM10 at 14.0 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.75
- 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).
A summer fog for fair, a winter fog for rain.
- Moonrise
- 6:30 AM
- Moonset
- 3:40 PM
- In sign
- ♒︎ Aquarius
Pikas hayfeeding in granite peaks
Meridian at a glance
- Today vs. normal: 5°F below the seasonal normal for this latitude
- Last frost: May 8 (climatological average for this latitude)
- Microseason: Jun 1–5
- Planting window: Harvest spring lettuce before it bolts. Sow heat-tolerant greens.
Right now in the garden
Warm-season window is open
As of June 4, the last spring frost has passed for most years. Transplant tomatoes, peppers, eggplants, basil, and cucurbits (cucumbers, squash, melons) now. Direct-sow beans and corn into warm soil.
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
Meridian's warmest month is July (~75°F mean) and its coldest is January (~31°F). Rainfall peaks in December (1.4 inches) and bottoms out in August (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
Meridian belongs to a warm-summer Mediterranean climate region — a cohort of cities with comparable temperature ranges, seasonal patterns, and growing conditions.
Similar climates: Boise, ID, Nampa, ID, Coeur d'Alene, ID, Caldwell, ID, Post Falls, 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?
- Meridian's last spring frost typically falls around mid-May, and the first fall frost arrives around mid-October.
- What is the rainy season in Meridian?
- December is the wettest month with about 1.4 inches of rain on average; the city receives roughly 11 inches annually.
- What is the warmest month in Meridian?
- July is typically warmest, averaging about 75°F.
- What is the coldest month in Meridian?
- January is typically coldest, averaging about 31°F.
- When can I start a vegetable garden in Meridian?
- Cool-season crops (peas, lettuce) can be sown around the last spring frost (mid-May); warm-season crops (tomatoes, peppers) wait until 1–2 weeks after.
- How many rainy days does Meridian get?
- Meridian averages about 37 rainy days per year.
- What hardiness zone is Meridian?
- Meridian's USDA hardiness zone is determined by its lowest average winter temperature; check the USDA's online lookup with the city ZIP for the current zone designation.
Climate
Meridian, Idaho has a warm-summer Mediterranean climate. January averages 31°F and July averages 75°F — a 44°F swing between seasons.
The city receives about 11 inches of precipitation spread over roughly 37 rainy days per year.
Latitude (43.6°N), distance from large water bodies, and elevation all set the rhythm of the year — shaping what grows, when frost arrives, and how daily weather unfolds.