How to use
- Choose Celsius or Fahrenheit before entering values.
- Enter air temperature, relative humidity, surface temperature, and the planned time for the job.
- Check the dew point, the temperature gap, and the OK / Caution / Hold decision.
- Copy the share link when you want to pass the same inputs to someone else.
Formulas
- γ = ln(RH / 100) + (a × T) / (b + T)
- Td = (b × γ) / (a - γ)
- Gap = surface temperature - dew point
Σημειώσεις
- This checker is a practical field aid, not a substitute for product data sheets, site specifications, or supervisor instructions.
- Weather can change quickly. Recheck the surface temperature if the sun, wind, or cloud cover changes.
- All calculations stay in the browser. No input is sent to the server.
Συχνές ερωτήσεις
Why is the threshold 3°C / 5°F?
It gives a practical buffer above the dew point and is easy to remember on site.
Why is planned time not part of the calculation?
The decision should be based on measured temperature and humidity. Planned time is recorded only as a reminder.
Can I use Fahrenheit?
Yes. Switch the unit system and the tool will keep the same physical temperatures when you change units.
What does Caution mean?
The surface is still above the dew point, but the margin is too small for a comfortable paint window.
What if humidity is 100%?
The dew point will match the air temperature, so the surface must be clearly warmer to avoid condensation risk.