Is it good to paint in Casper, WY this week?
A live 7-day go/no-go calendar for exterior paint in Casper, 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
- 3.3°F
- Overnight dew
- High
- Rain
- 2%
- Window
- —
High condensation risk overnight — surface dips to within 3.3°F of the 42°F dew point (low 44°F, 0% cloud, 4 mph wind). A fresh paint can blush/blister. Stop 4h before dew falls.
- Dew margin
- 2.9°F
- Overnight dew
- High
- Rain
- 2%
- Window
- —
High condensation risk overnight — surface dips to within 2.9°F of the 41°F dew point (low 43°F, 5% cloud, 6 mph wind). A fresh paint can blush/blister. Stop 4h before dew falls.
- Dew margin
- 14.4°F
- Overnight dew
- Low
- Rain
- 0%
- Window
- 8am–5pm
Clear to paint: temps 57–80°F, RH under 46%, surface stays 14.4°F+ above the dew point, no rain in the cure window.
- Dew margin
- -4.9°F
- Overnight dew
- High
- Rain
- 1%
- Window
- —
High condensation risk overnight — surface dips to within -4.9°F of the 43°F dew point (low 37°F, 0% cloud, 2 mph wind). A fresh paint can blush/blister. Stop 4h before dew falls.
- Dew margin
- 3.7°F
- Overnight dew
- High
- Rain
- 0%
- Window
- —
High condensation risk overnight — surface dips to within 3.7°F of the 38°F dew point (low 42°F, 0% cloud, 4 mph wind). A fresh paint can blush/blister. Stop 4h before dew falls.
- Dew margin
- 11.7°F
- Overnight dew
- Low
- Rain
- 1%
- Window
- 8am–5pm
Clear to paint: temps 63–80°F, RH under 38%, surface stays 11.7°F+ above the dew point, no rain in the cure window.
- Dew margin
- 17.3°F
- Overnight dew
- Low
- Rain
- 1%
- Window
- 8am–5pm
Clear to paint: temps 62–73°F, RH under 51%, surface stays 17.3°F+ above the dew point, no rain in the cure window.
- High condensation risk overnight — surface dips to within 3.3°F of the 42°F dew point (low 44°F, 0% cloud, 4 mph wind). A fresh paint can blush/blister. Stop 4h before dew falls.
- Cold mornings (down to 45°F, floor is 50°F) — wait for the surface to warm past midday before you paint.
Hold off. These are forecast numbers — confirm the surface temperature on-site before you start.
Why these thresholds
Overnight dew condensing on a fresh coat causes blistering, surfactant leaching and peeling — the cause of 40%+ of exterior paint failures.
- • Surface temp must stay 5°F above the dew point through application and cure (ASTM D3276 / ISO 8502-42).
- • Air + surface in the 50–85°F band (low-temp lines to 35°F).
- • Humidity under 85%; ideally under 70%.
- • 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.