Weather in Nampa, Idaho
High country wildflowers peak. Day 59 of spring. Read this microseason across nine climate regions →
When the dew is on the grass, rain will never come to pass.
- Moonrise
- 12:24 PM
- Moonset
- 3:45 AM
- In sign
- ♊︎ Gemini
High country wildflowers peak
Nampa at a glance
- Today vs. normal: NaN°F below the seasonal normal for this latitude
- Last frost: May 8 (climatological average for this latitude)
- Microseason: 28 of 72, May 16–20
- Planting window: Direct sow okra, melons, and southern peas. Thin carrot rows.
Right now in the garden
Cool-season window is open
As of May 17, the cool-season window is open or about to open. Direct-sow peas, lettuce, spinach, radishes, and brassicas now. Hold off on warm-season crops until 1–2 weeks after the last spring frost (around May).
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
July brings Nampa's warmest temperatures (~75°F mean) while January delivers the coldest (~31°F). December sees peak rainfall at 1.4 inches, with August receiving the least 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
Nampa falls within a warm-summer Mediterranean climate region. This places it among nearby cities that share similar temperature ranges, seasonal patterns, and growing conditions.
Similar climates: Boise, ID, Coeur d'Alene, ID, Meridian, ID, Caldwell, ID, Post Falls, ID.
Naturalist notes
By late May, western meadowlarks establish their territories across Nampa's grasslands, their distinctive yellow breasts visible as they perch on fence posts.
Serviceberry bushes bloom throughout the Treasure Valley in April, their white clusters appearing just as the last frost risk passes.
Frequently asked
- When does it freeze in Nampa?
- Spring's last frost typically occurs around mid-May in Nampa, while the first fall frost arrives around mid-October.
- What is the rainy season in Nampa?
- December brings the most precipitation with about 1.4 inches of rain on average. The city receives roughly 11 inches annually.
- What is the warmest month in Nampa?
- July typically brings the warmest weather, averaging about 75°F.
- What is the coldest month in Nampa?
- January typically brings the coldest temperatures, averaging about 31°F.
- When can I start a vegetable garden in Nampa?
- Cool-season crops like peas and lettuce can be planted around the last spring frost in mid-May. Warm-season crops such as tomatoes and peppers should wait until 1–2 weeks after.
- How many rainy days does Nampa get?
- Nampa experiences about 37 rainy days per year on average.
- What hardiness zone is Nampa?
- Nampa's USDA hardiness zone depends on its lowest average winter temperature. Check the USDA's online lookup tool with the city ZIP code for the current zone designation.
Climate
Nampa, Idaho experiences a warm-summer Mediterranean climate zone. January temperatures hover near 31°F while July averages 75°F — a 44°F seasonal swing.
Throughout the year, Nampa receives about 11 inches of precipitation spread over roughly 37 rainy days.
Local weather patterns depend on latitude (43.6°N), proximity to large water bodies, and elevation. These factors determine what grows here, when frost strikes, and the daily weather patterns.