Vandalia, Missouri Weather
Fireflies pulse through the magnolias. Day 77 of spring. Read this microseason across nine climate regions →
Vandalia weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 4Overcast——85°57°—
- FridayJun 5Overcast20%—85°69°0°
- SaturdayJun 6Drizzle20%—85°68°0°
- SundayJun 7Showers54%0.04″82°69°-3°
- MondayJun 8Showers61%0.32″81°69°-1°
- TuesdayJun 9Thunderstorm36%—86°67°+5°
- WednesdayJun 10Thunderstorm15%—90°74°+4°
Ozone at AQI 33. AQI down 30 over the last 6 hours — air quality is improving sharply. Overcast through the UV peak window (cloud cover ~61%) — afternoon ozone should stay flat.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion during the projected peak around 7 AM.
What's driving it
Ozone × UV × Sky
Ozone at AQI 33. Overcast through the UV peak window (cloud cover ~61%) — afternoon ozone should stay flat.
- Present
- AQI 33
- UV peak
- 3.3 at 1 PM
- Sky at peak
- overcast
- Projected peak
- AQI 7
PM × Wind × Precip
PM2.5 at 5.0 µg/m³ (AQI 28) with a 0.94 fine-to-coarse ratio and 6 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.94
- Wind
- light
- Recent rain
- 0h in last 6h
- Pattern
- stagnant smoke
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
- 4:33 AM
- Moonset
- 2:10 PM
- In sign
- ♑︎ Capricorn
Fireflies pulse through the magnolias
Vandalia at a glance
- Today vs. normal: 14°F below the seasonal normal for this latitude
- Last frost: April 12 (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 4, 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 — Vandalia
SPC has placed Vandalia in the General Thunderstorms category for severe thunderstorms today.
- TODAYTSTMGeneral Thunderstorms
- TOMORROWTSTMGeneral Thunderstorms
- DAY 3TSTMGeneral Thunderstorms
Thunderstorms possible. Not severe, but capable of producing lightning and brief heavy rain.
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
Vandalia's warmest month is July (~76°F mean) and its coldest is January (~27°F). Rainfall peaks in June (5.1 inches) and bottoms out in December (2.0 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 27° | 2.2″ | 4 |
| February | 32° | 2.3″ | 4 |
| March | 42° | 3.4″ | 7 |
| April | 53° | 4.2″ | 7 |
| May | 63° | 5.0″ | 8 |
| June | 73° | 5.1″ | 7 |
| July | 76° | 4.6″ | 7 |
| August | 75° | 3.4″ | 5 |
| September | 67° | 3.7″ | 5 |
| October | 55° | 2.8″ | 6 |
| November | 43° | 2.7″ | 5 |
| December | 32° | 2.0″ | 5 |
Regional context
Vandalia's baseline climate, derived from NOAA NCEI 1991-2020 normals at the nearest reporting station, swings from a January mean of 27°F to a July mean of 76°F — a 49°F seasonal arc typical of the mid-latitude bands. Annual precipitation runs about 41.3 inches spread across roughly 71 days with measurable rain or snow each year.
Precipitation runs summer-dominant here: June averages 5.1 inches across 7.2 days with measurable rain, driven mostly by warm-season storms and thunderstorm activity, while December drops to just 2.0 inches across 4.5 rainy days under drier cool-season air. That summer-storm-driven distribution puts Vandalia in a cohort with places like Farber, MO, Curryville, MO and Laddonia, MO, all of which depend on warm-season convective activity for the bulk of their 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-soil crops — tomatoes, peppers, eggplant — wait until soil temperatures reach the mid-50s°F, usually two weeks past the last-frost date. 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 Vandalia, 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: Farber, MO, Curryville, MO, Laddonia, MO, Perry, MO, Middletown, MO.
Frequently asked
- When does it freeze in Vandalia?
- Vandalia's last spring frost typically falls around mid-April, and the first fall frost arrives around mid-November.
- What is the rainy season in Vandalia?
- June is the wettest month with about 5.1 inches of rain on average; the city receives roughly 41 inches annually.
- What is the warmest month in Vandalia?
- July is typically warmest, averaging about 76°F.
- What is the coldest month in Vandalia?
- January is typically coldest, averaging about 27°F.
- When can I start a vegetable garden in Vandalia?
- 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 Vandalia get?
- Vandalia averages about 71 rainy days per year.
- What hardiness zone is Vandalia?
- Vandalia'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
Vandalia, Missouri sits in a humid subtropical climate zone. January means hover near 27°F while July averages 76°F — a 49°F seasonal swing.
Across the year, Vandalia receives about 41 inches of precipitation spread over roughly 71 rainy days.
The rhythm of the year is set by latitude (39.3°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.