Is it good to coat in Boston, MA this week?
A live 7-day go/no-go calendar for epoxy & resin floors in Boston, built from the local forecast against the 5°F-above-dew-point rule. We lead with the signal a weather app misses: overnight condensation risk.
- Dew margin
- 4.9°F
- Overnight dew
- High
- Rain
- 2%
- Window
- —
High condensation risk overnight — surface dips to within 4.9°F of the 60°F dew point (low 65°F, 0% cloud, 4 mph wind). A fresh coat can blush/blister. Stop 4h before dew falls.
- Dew margin
- 6.7°F
- Overnight dew
- Low
- Rain
- 9%
- Window
- 8am–5pm
Clear to coat: temps 72–85°F, RH under 71%, surface stays 6.7°F+ above the dew point, no rain in the cure window.
- Dew margin
- 10.5°F
- Overnight dew
- Low
- Rain
- 28%
- Window
- 8am–5pm
Hot afternoon (86°F, ceiling 86°F) — coat early and follow the shade.
- Dew margin
- 3°F
- Overnight dew
- Watch
- Rain
- 28%
- Window
- —
Rain likely in the 24h cure window (28% chance, ~8.6mm) — it can wash out or mar an uncured coat.
- Dew margin
- 11°F
- Overnight dew
- Low
- Rain
- 1%
- Window
- 8am–5pm
Clear to coat: temps 63–76°F, RH under 63%, surface stays 11°F+ above the dew point, no rain in the cure window.
- Dew margin
- 0.8°F
- Overnight dew
- High
- Rain
- 53%
- Window
- —
High condensation risk overnight — surface dips to within 0.8°F of the 68°F dew point (low 64°F, 100% cloud, 9 mph wind). A fresh coat can blush/blister. Stop 4h before dew falls.
- Dew margin
- 9.8°F
- Overnight dew
- Low
- Rain
- 53%
- Window
- —
Humidity peaks at 97% — well above the 85% ceiling; cure stalls and moisture gets trapped.
- High condensation risk overnight — surface dips to within 4.9°F of the 60°F dew point (low 65°F, 0% cloud, 4 mph wind). A fresh coat can blush/blister. Stop 4h before dew falls.
- Hot afternoon (87°F, ceiling 86°F) — coat early and follow the shade.
Hold off. These are forecast numbers — confirm the surface temperature on-site before you start.
Why these thresholds
Installing within 5°F of the dew point causes amine blush / carbamation — a cloudy, greasy, hazed floor. The slab surface temp, not the air, is what counts.
- • Surface temp must stay 5°F above the dew point through application and cure (ASTM D3276 / ISO 8502-42).
- • Air + surface in the 50–86°F band (low-temp lines to 50°F).
- • Humidity under 85%; ideally under 80%.
- • No rain for 24h after application.
- • We use the forecast ground-surface temperature as a surface-temp proxy — confirm on-site with an IR thermometer.
Free in the beta
Watch this job site 24/7
Get an email the moment overnight dew, rain, or an out-of-range stretch threatens a fresh coat — and a morning digest with the best window ahead. No app to check; we watch the forecast for you.