Concrete Pouring Weather in Bloomington, IN: 10-Day Windows & Best Months
In Bloomington, the label math works from April through October: that's the stretch with 8+ workable days a month against typical concrete pouring rules. The single best month is August, averaging 23 days that clear every check — highs of 84°F, lows near 64°F, and a 26% daily rain chance. The strip above runs Bloomington's live forecast; the table below ranks all 12 months.
GOOD — clears every rule MARGINAL — exactly one soft miss NO — a hard fail, or two soft
The rules this check uses
Every verdict above applies this table to Bloomington's hours. DIY scope only: the freeze row outranks everything, and structural work belongs to engineer/ACI specifications.
| Check | Threshold | Why it matters |
|---|---|---|
| Air temperature | 40–90°F — ideal 50–85°F | Checked across the working day, 8 a.m.–6 p.m., against Bloomington's hourly forecast — not just the daily high. |
| Overnight low | ≥40°F during the first 48 h | The engine reads every overnight hour in the cure window, not just Bloomington's forecast low. |
| Dry before | no soaking (≥1.0") in the prior 24 h | Rain before the pour only matters if the ground is soaked or standing in water. |
| Dry after | <0.1" rain for 6 h after (12 h light rain after finishing still risks surface marks) | A downpour in the first 6 hours can wash the surface; after final set, rain actually helps curing. |
| Wind | ≤20 mph (rapid surface drying up to 28 mph) | Wind wrecks application first (drift, lap marks) and carries debris into wet work second. |
Always follow your product label — formulas vary. These rows are the industry-typical range; the can in your Bloomington garage is the contract.
Best months for concrete pouring in Bloomington
| Month | Avg high | Avg low | Rain odds/day | Workable days | |
|---|---|---|---|---|---|
| January | 37°F | 21°F | 36% | 0 | |
| February | 42°F | 23°F | 34% | 0 | |
| March | 52°F | 32°F | 35% | 0 | |
| April | 64°F | 42°F | 41% | 12 | |
| May | 74°F | 53°F | 42% | 18 | |
| June | 82°F | 62°F | 37% | 19 | |
| July | 85°F | 65°F | 31% | 21 | |
| August | 84°F | 64°F | 26% | 23 | |
| September | 78°F | 56°F | 24% | 23 | |
| October | 66°F | 44°F | 29% | 21 | |
| November | 53°F | 34°F | 32% | 0 | |
| December | 41°F | 26°F | 36% | 0 |
Figure 137 workable days a year in Bloomington, spread across April through October. Shoulder months turn on the overnight rule: an afternoon at 64°F passes, but the 40°F night floor is what actually opens the season in April. For the statewide picture, the Indiana page compares peak months city by city.
Sealing the same driveway later? Sealcoating in Bloomington wants warmer nights (50°F+) than the pour did.
Numbers above come from NOAA's 1991–2020 normals for Bloomington Indiana Univ, In Us, 1.2 km from the city center — close enough that neighborhood microclimates (shade lines, river valleys, urban heat) matter more than station distance. See how these day counts are scored.
Bloomington by the numbers
- July is Bloomington's heat peak: 85°F typical high, 0 days over 90°F.
- Coldest month: January — 37°F highs over 21°F nights.
- Wet-to-dry spread: 42% rain days in May versus 24% in September.
- Overnight lows clear 40°F from April to October in a normal year.
- Add it up and Bloomington banks 137 workable days a year for concrete pouring.
Prep checklist
- Clear the 48-hour rule first: two nights over 40°F. April opens that door in Bloomington; January (21°F average lows) slams it.
- Set the stage first: forms braced, subgrade compacted and lightly damp, every tool within reach, help confirmed.
- Cut plastic sheeting and weight it at the pour's edge — Bloomington sees rain on 26% of August days, and the 6-hour rule doesn't negotiate.
- Keep the mix stiff (oatmeal, not soup) — every extra quart of water is permanent surface strength lost.
- Screed while it sheens, float when the sheen dulls, and never trowel bleed water back in.
- Edge and joint with an edger + float set — control joints every 2–3 slab-thicknesses in feet.
- Hold the moisture in (sheeting or misting); when October nights dip toward 44°F, a curing blanket is the difference.
- Feet after 24–48 h, cars after about a week — and structural work follows engineer/ACI specs, not this list.
Gear that saves a window
FTC note: the gear below is unlinked until the affiliate program is switched on. See the affiliate disclosure.
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Edger + float set
Rounded edges and a flat surface before it sets.
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Concrete mix
An 80-lb bag yields about 0.6 cu ft — do the math twice.
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IR surface thermometer
Track slab temperature, not just the forecast.
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Curing blanket
Holds heat through cold nights in the critical 48 hours.
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Plastic sheeting
Emergency rain cover and moisture-holding cure layer.
FAQ
What temperature is too cold to pour concrete?
The line is a 40°F low inside the first 48 hours; an actual freeze (32°F) physically damages young concrete. Bloomington's January nights average 21°F — firmly out — while August nights hold near 64°F. Small pours only; structural work follows engineer/ACI specs.
Can you pour concrete before rain?
The engine wants 6 protected hours; light rain later actually feeds the cure. With 42% rain-day odds in May versus 24% in September, Bloomington's dry-season pours barely think about this rule and wet-season pours live by the radar. For small DIY pours; structural schedules follow ACI.
How long does concrete need to be protected from freezing?
Keep it above freezing for at least the first 48 hours (the engine calls any sub-40°F low in that window a NO). In Bloomington that rules out roughly January-adjacent months entirely and makes shoulder-season pours a two-night forecast decision. DIY scope; anything structural follows engineer/ACI cold-weather practice.
Is it OK to pour concrete in hot weather?
To a 90°F high, yes — with shade, cool mix water, a damp subgrade, and a dawn start. Above 90°F the surface sets while the core is plastic and shrinkage cracks map the slab. Bloomington averages 0 such days in July — rarely the binding constraint here.
How long before you can drive on new concrete?
A week before tires, 24–48 hours before feet — at August-typical Bloomington temperatures (84°F highs). When nights slide toward 21°F, add days: cure speed is temperature. Early loads print permanent marks; the bag's cure table wins every argument.
Best season for concrete work in Bloomington?
April through october — the months with 40°F+ nights, sub-90°F days, and manageable rain. August leads at 23 workable days; January bottoms out near 0.
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Guides
Climatology: NOAA 1991–2020 normals via BLOOMINGTON INDIANA UNIV, IN US (1.2 km from Bloomington center, elevation 830 ft); live outlook by Open-Meteo.