Today’s work window has closed
Concrete weather in Oʻahu today
Concrete is all about the pour and the cure — rain during placement, plastic-shrinkage cracking in hot dry wind, and a freeze before it sets are the three ways weather ruins a slab.
That’s a wrap for today.
Here’s how tomorrow (Thursday, July 30) is shaping up in Oʻahu: mostly limited — 3 of 14 spots workable · 11 limited. It’s an early look — the full, live area-by-area call refreshes each morning.
Check back in the morning for the live call.
Forecast refreshed each morning.
All 14 spots we forecast in Oʻahu · tomorrow
| Location | Tomorrow | Why & rain odds |
|---|---|---|
| Town (south shore) | ||
| Downtown Honolulu | Limited | evaporation at/above the ACI 305R cracking-risk line — pour only with active fog spray, wind breaks, or an evaporation retarder, or shift to a cooler/calmer window |
| Waikīkī / Kapahulu | Limited | evaporation at/above the ACI 305R cracking-risk line — pour only with active fog spray, wind breaks, or an evaporation retarder, or shift to a cooler/calmer window |
| Kalihi / Salt Lake / Airport | Limited | evaporation at/above the ACI 305R cracking-risk line — pour only with active fog spray, wind breaks, or an evaporation retarder, or shift to a cooler/calmer window |
| Hawaiʻi Kai / ʻĀina Haina | Workable | clear cure window |
| Mauka valleys | ||
| Mānoa / Makiki mauka | Limited | rain in the forecast during pour/finish — plan a dry window and check radar |
| Windward side | ||
| Kailua | Limited | rain in the forecast during pour/finish — plan a dry window and check radar |
| Kāneʻohe | Limited | rain in the forecast during pour/finish — plan a dry window and check radar |
| Waimānalo | Workable | clear cure window |
| Leeward side | ||
| Kapolei | Limited | evaporation at/above the ACI 305R cracking-risk line — pour only with active fog spray, wind breaks, or an evaporation retarder, or shift to a cooler/calmer window |
| ʻEwa Beach | Limited | evaporation at/above the ACI 305R cracking-risk line — pour only with active fog spray, wind breaks, or an evaporation retarder, or shift to a cooler/calmer window |
| Waiʻanae coast | Workable | clear cure window |
| Central Oʻahu | ||
| Mililani / Waipiʻo | Limited | evaporation at/above the ACI 305R cracking-risk line — pour only with active fog spray, wind breaks, or an evaporation retarder, or shift to a cooler/calmer window |
| Wahiawā | Limited | evaporation at/above the ACI 305R cracking-risk line — pour only with active fog spray, wind breaks, or an evaporation retarder, or shift to a cooler/calmer window |
| North Shore | ||
| Haleʻiwa / North Shore | Limited | evaporation at/above the ACI 305R cracking-risk line — pour only with active fog spray, wind breaks, or an evaporation retarder, or shift to a cooler/calmer window |
Chance = odds, over work hours, of rain heavy enough to disrupt a concrete day. Not recommended is our call, not a rule — the risk to the work is real, so we'd wait; limited means it's workable with care. Either way it's your crew, so check the sky and radar before you commit.
This is today's snapshot. The next 7 days for your area — the closest point we forecast to your ZIP, with the reasons behind every caution and stop, refreshed each morning — are what the free Sunday brief delivers.
What's driving the tomorrow call
What's stopping some areas
- evaporation at/above the ACI 305R cracking-risk line — pour only with active fog spray, wind breaks, or an evaporation retarder, or shift to a cooler/calmer window
- rain in the forecast during pour/finish — plan a dry window and check radar
Precautions & technique
- evaporation at the action line — plan fog spray, esp. blended cements
- high heat — rest and water cycles
- hot — keep mix under 95° at discharge, cure fast
Forecast-derived estimate, not a live sensor reading.
What the temperature means for concrete tomorrow
Tomorrow runs about 5° warmer than a typical July (88° vs a 83° normal) — hot, dry, windy air raises the plastic-shrinkage cracking risk, so plan fogging or wind-breaks on the pour. See the breakdown above for what's driving the call tomorrow.
Source≈10-yr ERA5 reanalysis (Open-Meteo), 2015–2024
Get the full 7-day concrete plan for your ZIP
Your area's likely workdays, caution windows, and weather stops — with the reasons — before you schedule the crew.
Next 7 days, Oʻahu-wide
This is the metro-wide shape. The free Sunday brief pins each day to the area we forecast nearest your ZIP — with the reasons behind every caution and stop — for every trade you run.
What controls a concrete day in Oʻahu
Around Oʻahu, the concrete calendar tracks the weather more than the date — Oʻahu sees year-round trade-wind warmth, wetter in winter, with windward showers that often skip leeward. Hot, dry, windy stretches are when to watch plastic-shrinkage cracking, and if it turns cold, cold-weather protection comes in.
Most of these thresholds trace to the manufacturer specs and industry standards cited above; where no published number exists, we use a clearly-labeled conservative cutoff. Either way the physics is the same anywhere. What's specific to Oʻahu is when they line up, which is exactly what the live area-by-area call at the top of this page tracks each day.
When concrete gets tricky in Oʻahu
Rain stays fairly steady month to month here, so a concreteday comes down to the daily forecast and which part of the metro you're in more than the season. It stays warm enough year-round that cold-weather protection rarely comes in — it's rain and summer heat that set the Oʻahu concrete calendar. Source ≈10-yr ERA5 reanalysis (Open-Meteo), 2015–2024
Common questions
How cold is too cold to pour concrete in Oʻahu?
Below about 40°F, ACI 306R cold-weather protection applies (blankets, heated enclosures) and cure slows sharply — that's a protect-the-pour trigger, not an automatic stop. The real danger is a freeze within roughly 48 hours, before the concrete reaches about 500 psi. Our call flags both the cold and an early freeze in the cure window.
Can you pour concrete before rain in Oʻahu?
Rain during placement or before the surface has set marks and weakens it (ACI 301). Plan a dry window through placement and initial set — our daily call flags rain across the pour and the cure horizon.
What is the evaporation-rate warning for concrete?
Hot, dry, windy conditions pull water out of fresh concrete and cause plastic-shrinkage cracking. We compute the ACI 305R evaporation rate: around 0.1 lb/ft²/hr we flag fogging and wind-break precautions, and at 0.2 we'd wait.