Altoona, Iowa Weather
Prairie lightning bugs rise. Day 78 of spring. Read this microseason across nine climate regions →
Altoona weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 5Thunderstorm77%0.26″81°66°—
- SaturdayJun 6Thunderstorm33%—85°68°+4°
- SundayJun 7Light Showers69%0.01″80°68°-5°
- MondayJun 8Heavy Drizzle69%—80°66°0°
- TuesdayJun 9Thunderstorm24%—87°69°+7°
- WednesdayJun 10Thunderstorm11%—89°73°+2°
- ThursdayJun 11Light Drizzle15%—88°71°-1°
AQI 38 (Good), driven by PM2.5. AQI down 10 over the last 6 hours (steady decline since this morning). PM scrubbed by 2 hours of recent rain — PM2.5 down to 8.3 µg/m³, PM10 to 8.8 µg/m³.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
PM × Wind × Precip
PM scrubbed by 2 hours of recent rain — PM2.5 down to 8.3 µg/m³, PM10 to 8.8 µg/m³.
- PM2.5/PM10
- 0.94
- Wind
- breezy
- Recent rain
- 2h in last 6h
- Pattern
- washed out
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).
The higher the clouds, the finer the weather.
- Moonrise
- 5:19 AM
- Moonset
- 3:17 PM
- In sign
- ♒︎ Aquarius
Prairie lightning bugs rise
Altoona at a glance
- Today vs. normal: 7°F below the seasonal normal for this latitude
- Last frost: April 26 (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
Peak growing season
As of June 5, 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.
SPC Convective Outlook
Storm Prediction Center — Altoona
SPC has placed Altoona in the Slight Risk category for severe thunderstorms tomorrow.
- TODAYMRGLMarginal Risk
- TOMORROWSLGTSlight Risk
- DAY 3TSTMGeneral Thunderstorms
Scattered severe storms possible. A few tornadoes, hail, and damaging wind gusts possible.
Source: NOAA / NWS Storm Prediction Center categorical convective outlook. Outlooks are re-issued multiple times per day; this page reflects the most recent SPC polygons covering the city’s coordinates.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | — | — |
| February | — | — |
| March | — | — |
| April | lettuce, peas, spinach, radishes | — |
| May | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| June | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | tomatoes, peppers, beans, squash | tomatoes, beans, summer squash |
| August | — | tomatoes, beans, summer squash |
| September | fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| October | fall brassicas, garlic (overwinter), carrots | winter squash, tomatoes (last) |
| November | — | — |
| December | — | — |
A year in weather
Altoona's warmest month is July (~75°F mean) and its coldest is January (~21°F). Rainfall peaks in June (5.4 inches) and bottoms out in January (1.0 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 21° | 1.0″ | 3 |
| February | 25° | 1.0″ | 3 |
| March | 37° | 2.0″ | 5 |
| April | 50° | 4.0″ | 7 |
| May | 61° | 5.3″ | 9 |
| June | 71° | 5.4″ | 8 |
| July | 75° | 4.2″ | 6 |
| August | 73° | 4.7″ | 7 |
| September | 65° | 3.6″ | 5 |
| October | 52° | 2.7″ | 5 |
| November | 38° | 1.9″ | 4 |
| December | 26° | 1.4″ | 3 |
Regional context
Altoona's baseline climate, derived from NOAA NCEI 1991-2020 normals at the nearest reporting station, swings from a January mean of 21°F to a July mean of 75°F — a 55°F seasonal arc typical of the mid-latitude bands. Annual precipitation runs about 37.1 inches spread across roughly 64 days with measurable rain or snow each year.
Precipitation runs summer-dominant here: June averages 5.4 inches across 7.5 days with measurable rain, driven mostly by warm-season storms and thunderstorm activity, while January drops to just 1.0 inches across 2.5 rainy days under drier cool-season air. That wet-warm-summer pattern groups Altoona with places like Bondurant, IA, Pleasant Hill, IA and Mitchellville, IA — a regional cohort where summer thunderstorm season carries more than half the annual moisture.
The frost-sensitive growing window opens around mid-April, when overnight lows reliably clear freezing for cool-season crops like kale, peas, spinach, and parsnips. Warm-season transplants — tomatoes, peppers, and basil — typically wait two weeks past that date to avoid late spring cold snaps. The window closes around mid-November, when overnight lows resume dipping below freezing and frost-tender plants need protection or harvest. The dates above are 1991-2020 normals; in a given year either bookend can move 1-2 weeks either direction. Within Altoona, low-lying parcels along drainage features typically lose 4-7°F of overnight low temperature versus the bench positions on calm clear nights, which shifts the working last-frost date by a week or more.
Similar climates: Bondurant, IA, Pleasant Hill, IA, Mitchellville, IA, Saylorville, IA, Ankeny, IA.
Frequently asked
- When does it freeze in Altoona?
- Altoona's last spring frost typically falls around mid-April, and the first fall frost arrives around mid-November.
- What is the rainy season in Altoona?
- June is the wettest month with about 5.4 inches of rain on average; the city receives roughly 37 inches annually.
- What is the warmest month in Altoona?
- July is typically warmest, averaging about 75°F.
- What is the coldest month in Altoona?
- January is typically coldest, averaging about 21°F.
- When can I start a vegetable garden in Altoona?
- Cool-season crops (peas, lettuce) can be sown around the last spring frost (mid-April); warm-season crops (tomatoes, peppers) wait until 1–2 weeks after.
- How many rainy days does Altoona get?
- Altoona averages about 64 rainy days per year.
- What hardiness zone is Altoona?
- Altoona'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
Altoona, Iowa sits in a warm-summer humid continental climate zone. January means hover near 21°F while July averages 75°F — a 55°F seasonal swing.
Across the year, Altoona receives about 37 inches of precipitation spread over roughly 64 rainy days.
The rhythm of the year is set by latitude (41.6°N), proximity to large water bodies, and elevation — all of which shape what grows here, when frost is likely, and what the weather story looks like day to day.