PourDay concrete evaporation rate app icon
Free for Contractors

Know Your Concrete
Evaporation Rate Before You Pour.

PourDay uses the ACI 305R evaporation formula and real-time weather data to calculate your concrete evaporation rate and tell you whether conditions are safe to pour — before your ready-mix crew ever leaves the yard.

POURDAY
64108 — Kansas City, MO
Evaporation Rate
0.14
lb/ft²/hr
GO
Temp
78°F
Humidity
52%
Wind
8 mph
Concrete
72°F
120,000+
Concrete contractors in the US
0.15 lb/ft²/hr
The ACI threshold that matters
16-Day
Forecast window

Every Bad Pour Costs You.
Time. Money. Crew Confidence.

You check the weather, make a gut call, and hope for the best. But weather apps weren't built for concrete.

Concrete Surface Sets Too Fast

High evaporation conditions accelerate moisture loss, making finishing nearly impossible and compromising the surface before your crew can work it.

Plastic Shrinkage Cracking

When surface moisture evaporates faster than bleed water replaces it, cracks form within hours. Callbacks, repairs, and lost trust follow.

Reactive Decisions Cost Money

Canceling a pour last minute means idle crews, wasted ready-mix, and schedule chaos. Proactive decisions save thousands per job.

Four Steps. Zero Guesswork.

PourDay replaces gut calls with data-driven decisions in seconds.

01

Open the App at Your Jobsite

Launch PourDay on your phone or any device. Input your location and get current weather conditions for your job site.

02

PourDay Calculates Evaporation Rate

Using the evaporation rate calculation based on ACI 305R and live weather data — temperature, humidity, wind speed, and concrete temperature — PourDay computes your real-time evaporation rate.

03

Log Conditions & Document Every Pour

Capture weather, evaporation rate, mix design, and supplier info automatically. Build a complete record your crew and project managers can rely on.

04

Plan Ahead with the 16-Day Forecast

Schedule around or plan for high evaporation based on our 16-day forecast and hourly projections. Stay proactive, not reactive.

Engineered for Concrete Professionals.

Every feature exists because a concrete contractor asked for it.

Real-Time ACI 305R Scoring

Real-time evaporation rate computed from current weather conditions, updated continuously throughout the day.

16-Day Job Site Forecast

Plan pours up to 16 days out. See projected evaporation rates and status indicators for every day in the forecast window.

Pour Log & PDF Reports

Log every pour with conditions, mix design, and outcome. Generate PDF reports for QA documentation and project records.

Works Nationwide

PourDay works for any job site in the US. Enter your zip code and get hyper-local conditions for your exact location.

Free for Contractors

No subscription, no paywall, no premium tier. PourDay is built for the concrete industry and free to use.

“Especially with the changes in cement in the last 2 years, if you are not tracking and scheduling around evaporation for slab pours you are putting yourself at risk.”
Doug S. — Concrete Contractor, Kansas City

Every Pour. Documented.

From ticket to finish, PourDay captures the data that protects your work and keeps your crew accountable.

Log Every Mix Design & Supplier

Record mix details, concrete supplier, and ticket numbers for every load that hits your site.

Track Pour Conditions in Real Time

Automatically capture weather, evaporation rate, and GO/NO GO status at the time of each pour.

Protect Your Work with a Paper Trail

When a crack shows up six months later, your pour log proves the conditions were right.

Share Reports with Your Team

Export pour logs and mix records for project managers, inspectors, and engineers.

Questions. Answers.

What is a safe evaporation rate for concrete?

ACI 305R recommends taking precautions when the concrete evaporation rate exceeds 0.15 lb/ft²/hr. Above this threshold, surface moisture evaporates faster than bleed water can replace it, causing plastic shrinkage cracking — especially critical with blended cements like Type 1L. PourDay calculates this automatically using live weather data for your job site.

How do I know if it's safe to pour concrete today?

Safe pour conditions depend on four variables: air temperature, relative humidity, wind speed at 18 inches above the slab, and concrete temperature. PourDay plugs your real-time job site weather into the ACI 305R evaporation formula and gives you a GO, CAUTION, or NO GO in seconds — no math, no nomograph.

How do I prevent plastic shrinkage cracking in concrete?

Plastic shrinkage cracking is caused by high evaporation conditions pulling moisture from fresh concrete before bleed water can replace it. When rates exceed 0.15 lb/ft²/hr, use evaporation retarders, erect wind breaks, adjust pour timing, or lower concrete temperature. PourDay shows you the real-time evaporation rate for your exact job site before every pour.

What is evaporation rate and why does it matter?

Evaporation rate measures how fast moisture leaves the surface of fresh concrete. ACI 305R recommends precautions above 0.15 lb/ft²/hr to prevent plastic shrinkage cracking — especially critical with blended cements like Type 1L.

How accurate is the forecast?

We use Open-Meteo, a professional-grade weather API. 0–3 days is highly reliable. 4–16 days is directional planning guidance.

Does it work outside my area?

PourDay works anywhere in the US. Enter your job site zip code and get real-time conditions for your exact location.

Can I log my mix designs and pours?

Yes. PourDay lets you log every mix design, supplier, and pour — automatically capturing weather conditions and evaporation data at the time of placement. Build a complete history across all your jobs.

Is PourDay really free?

Yes. PourDay is completely free for contractors. No subscription, no in-app purchases, no premium tier. We built it to help the industry make better pour decisions.

Know Before You Pour.

Real-time evaporation data. Mix and pour logging. Built for concrete crews.

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