Is it good to paint in Rapid City, SD this week?
A live 7-day go/no-go calendar for exterior paint in Rapid City, 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
- 3.4°F
- Overnight dew
- Watch
- Rain
- 19%
- Window
- 10am–3pm
Watch overnight dew — surface comes within 3.4°F of the dew point (margin is 5°F). Time the coat to dry well before evening.
- Dew margin
- 11.8°F
- Overnight dew
- Low
- Rain
- 0%
- Window
- 8am–5pm
Clear to paint: temps 57–76°F, RH under 70%, surface stays 11.8°F+ above the dew point, no rain in the cure window.
- Dew margin
- 6.3°F
- Overnight dew
- Low
- Rain
- 2%
- Window
- 8am–5pm
Clear to paint: temps 58–76°F, RH under 52%, surface stays 6.3°F+ above the dew point, no rain in the cure window.
- Dew margin
- 6°F
- Overnight dew
- Low
- Rain
- 13%
- Window
- 8am–5pm
Clear to paint: temps 53–64°F, RH under 71%, surface stays 6°F+ above the dew point, no rain in the cure window.
- Dew margin
- 8.5°F
- Overnight dew
- Low
- Rain
- 18%
- Window
- 10am–5pm
Cold mornings (down to 44°F, floor is 50°F) — wait for the surface to warm past midday before you paint.
- Dew margin
- 14.2°F
- Overnight dew
- Low
- Rain
- 7%
- Window
- 8am–5pm
Clear to paint: temps 56–64°F, RH under 64%, surface stays 14.2°F+ above the dew point, no rain in the cure window.
- Dew margin
- 12.2°F
- Overnight dew
- Low
- Rain
- 1%
- Window
- 8am–5pm
Clear to paint: temps 50–68°F, RH under 48%, surface stays 12.2°F+ above the dew point, no rain in the cure window.
- Watch overnight dew — surface comes within 3.4°F of the dew point (margin is 5°F). Time the coat to dry well before evening.
- High humidity (91%, over the 85% mark) slows drying — keep an eye on the cure window.
Caution. 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.