DryWindowFind the right weather window for painting, sealing, coating and drying
Enter your town and choose a job. DryWindow checks the next 7 days hour by hour – temperature, humidity, dew point, rain and wind – and shows you the best time to start.
How DryWindow works
A normal weather app tells you if it will rain. But paint, sealant, concrete and coatings care about much more than rain. Each product has a temperature range it can be applied in, a humidity limit, a safe margin above the dew point (otherwise surfaces get wet with condensation), and a period afterwards when it must stay dry while it cures.
DryWindow does that checking for you:
- It loads a 7-day hourly forecast for your exact location, including dew point and rain probability.
- It tests every daylight hour against the rules for the job you picked, and marks why any hour fails.
- It checks every possible start time to make sure there are enough consecutive good hours for the work itself and enough rain-free hours afterwards for drying or curing. For concrete, it also checks for frost over the next 48 hours.
- It scores and ranks the windows from 0 to 100, so the most comfortable, lowest-risk slot comes first.
The rules each job uses
These are typical limits drawn from product data sheets and trade guidance. Your product may differ – the tin is always the final word.
| Job | Temperature | Humidity | Work time | Afterwards |
|---|---|---|---|---|
| Exterior paint (water-based) | 10–30°C | ≤ 85% | 4 h | 6 h dry |
| Exterior paint (oil-based) | 8–28°C | ≤ 85% | 4 h | 12 h dry |
| Decking oil / wood stain | 10–28°C | ≤ 80% | 3 h | 24 h dry |
| Fence & shed treatment | 8–30°C | ≤ 85% | 2 h | 6 h dry |
| Pouring concrete | 5–30°C | any | 4 h | 12 h dry, no frost 48 h |
| Patio / paving sealer | 10–30°C | ≤ 80% | 2 h | 24 h dry |
| Car ceramic coating | 10–30°C | ≤ 80% | 3 h | 12 h dry |
| Car wax / sealant | 10–30°C | ≤ 85% | 2 h | 4 h dry |
| Underseal / cavity wax | 10–30°C | ≤ 80% | 3 h | 8 h dry |
| Outdoor silicone sealant | 5–40°C | ≤ 90% | 1 h | 12 h dry |
| Drying washing outside | 8°C+ | ≤ 80% | 5 h | – |
Most jobs also require the air to be at least 2–4°C above the dew point and wind below 12–25 mph.
Guides
Best Weather for Exterior Painting: Temperature, Humidity and Dew Point
How warm, dry and calm it needs to be to paint walls, render, woodwork and metal outside – and how to read a forecast so the paint actually cures.
Dew Point Explained: Why Surfaces Get Wet When It Isn't Raining
What the dew point is, how it differs from humidity, and why it decides whether paint, sealant, coatings and washing dry properly.
Pouring Concrete in Cold or Wet Weather: A Practical UK Guide
Minimum temperatures, frost risk, rain and wind when laying a concrete slab, base or footing – plus how to protect fresh concrete.
Ceramic Coating and Paint Sealant: The Weather Rules That Decide the Finish
Ideal temperature, humidity and cure time for applying ceramic coatings, sealants and wax to a car outdoors – from a working mechanic.
Applying Underseal and Cavity Wax: Weather Checklist for Rust Protection
The temperature, humidity and drying conditions you need when undersealing a car or injecting cavity wax – and why doing it on a wet day traps rust in.
When to Oil or Stain Decking and Fences: Weather and Timing Guide
How dry the wood needs to be, the best temperature and humidity for decking oil, stain and fence treatments, and how long they need before rain.
Is It a Good Drying Day? The Science of Drying Washing Outside
What makes a good drying day – temperature, humidity, wind and dew point – and how to tell from a forecast whether washing will dry on the line.
Frequently asked questions
Is DryWindow free?
Yes. The tool is free to use with no sign-up. It is supported by advertising.
Where does the weather data come from?
Forecasts come from Open-Meteo, which combines national weather service models including the UK Met Office, ECMWF and DWD. Data is updated hourly.
How far ahead can it plan?
Seven days, hour by hour. Forecasts are most reliable for the next two to three days, so re-check before you start.
Why does it say there is no window when it is not raining?
Rain is only one rule. An hour can also fail because it is too cold, too humid, too windy, too close to the dew point, or dark – or because rain is forecast during the drying time afterwards.
Does it store my location?
Your last search is remembered only in your own browser so you do not have to retype it. We do not store your location on any server. See our privacy policy for details.
Can I trust the result over the instructions on the tin?
No – always follow the manufacturer's data sheet. DryWindow uses typical limits for each type of product; some specialist products have wider or narrower ranges.