The quick answer
GoodDayTo keeps the first screen simple: GO, WAIT or NOT TODAY, the activity, the best complete time window and one memorable explanation. Open the supporting details when you want the rain, wind, gust, temperature and daylight facts behind the result.
Pressure washing is a wet job, so this model does not demand perfectly dry weather. It is more tolerant of a light shower than Window Cleaning or Exterior Painting. It becomes deliberately stricter when persistent rain reduces visibility and cleanup value, when wind makes spray control difficult, when wet surfaces approach freezing, or when the selected job runs into darkness.
How the complete-job score works
Choose one, three or five hours. GoodDayTo searches for a continuous forecast block of that full length; it does not silently shorten a half-day job to one attractive hour. Each hour receives a pressure-washing score using air and apparent temperature, rain probability, forecast rain amount, sustained wind, gusts, UV, daylight and severe-weather codes. The complete block then keeps the strictest task, safety and time-of-day cap.
- Complete selected job
- Rain amount & probability
- Wind & gusts
- Air & apparent temperature
- Daylight
- Thunderstorm signals
- Freezing precipitation
- Honest equipment limits
GO
The whole requested job stays below the pressure-washing rain, wind and cold caution thresholds and remains in daylight. GO means the measured weather looks practical. It never certifies the machine, surface, detergent, runoff route or work method.
WAIT
The selected block contains a meaningful caution, or another complete block looks better. A total of at least 0.3 mm rain, 60% hourly probability, sustained wind of 24 km/h, gusts of 38 km/h, air temperature of 5°C or apparent temperature of 3°C prevents GO.
NOT TODAY
The job reaches a stronger task limit: at least 1 mm total rain, 80% probability in any selected hour, sustained wind of 32 km/h, gusts of 48 km/h, air temperature of 2°C, apparent temperature of 0°C, darkness or a stronger shared severe-weather cap.
Rain is treated differently from a dry-surface job
A tiny shower is not an automatic failure: the area is being wetted anyway. The model instead looks for a persistent or disruptive rain signal across the complete pressure-washing job. At least 1 mm total forecast rain, or an 80% probability in any selected hour, caps the result at NOT TODAY (45). At least 0.3 mm, or a 60% probability, caps it at WAIT (70).
These are conservative planning guardrails, not universal pressure-washing safety limits. Rain probability describes likelihood, while forecast amount helps distinguish a small signal from a wetter block. Local downpours can still differ from a forecast grid, and rain does not reveal whether drains are blocked or whether dirty runoff will reach a road, garden, watercourse or storm drain.
A practical final-hour example
Suppose the first two hours are mild and calm, but the third hour shows 85% rain probability and 1 mm. Averaging the three hours could make the job look acceptable. GoodDayTo instead caps the full block at NOT TODAY because the final period affects visibility, runoff, packing away and inspection. A 65% signal with 0.3 mm produces WAIT. A dry or genuinely light-shower block remains eligible for GO.
Wind and gusts apply to every selected hour
Sustained wind from 24 km/h, or gusts from 38 km/h, prevents GO. Sustained wind from 32 km/h, or gusts from 48 km/h, caps the complete job at NOT TODAY. Wind direction, surrounding walls and nozzle choice can change the real spray path, so the numbers are planning boundaries rather than equipment ratings.
The result details use the strongest wind and gust in the selected block instead of describing only the first hour. Even below these thresholds, stop if spray, loosened debris or detergent cannot be controlled around people, vehicles, glazing, plants, ventilation openings or neighbouring property.
Cold and darkness are complete-job limits
At 5°C air temperature or 3°C apparent temperature, the result cannot be GO. At 2°C air temperature or 0°C apparent temperature, it is capped at NOT TODAY. Wet paving, steps and driveways may stay cold or freeze, while hoses, seals, pumps and detergents can have manufacturer-specific temperature limits. Inspect the actual surface and follow the product manual even when the forecast remains above the GoodDayTo boundary.
Pressure washing is treated as a daylight job. If any selected hour is after dark, the complete window keeps the strict after-dark cap because GoodDayTo cannot verify task lighting, trip hazards, electrical leads, hose position, overspray or surface damage. A floodlight does not automatically remove those uncertainties.
Which duration should you choose?
Use one hour for a small section, bin, garden item or quick rinse. Use three hours for an ordinary patio, driveway or paving job. Choose five hours only for a real half-day project. Include setup, pretreatment, moving furniture, the wash itself, rinsing, cleanup and packing away whenever those stages keep you outside.
The Planner and saved routines use the same complete-job rules as this page. If a later full-length block is materially better, GoodDayTo can recommend it. It will not claim a one-hour gap solves a five-hour plan.
Safety checks weather cannot replace
The CDC pressure-washer guidance warns never to point the jet at yourself or another person, highlights electrical hazards, and says gasoline-powered machines must not be used in enclosed or partially enclosed spaces because carbon monoxide can accumulate. A weather score cannot see where the engine or electrical connection is placed.
OSHA guidance on high-pressure cleaning documents injection, noise and uncontrolled-hose hazards. Home machines and professional equipment differ, so use the correct nozzle, pressure, guarding, protective equipment and manufacturer procedure for the actual task. GoodDayTo never converts favourable weather into permission to aim the jet at skin, animals, live electrical equipment or fragile materials.
Thunderstorms override ordinary job comfort. The National Weather Service advises going to a substantial building or hard-topped vehicle when thunder is heard and waiting 30 minutes after the last thunder before returning outside. A porch, open garage or small shelter is not treated as reliable lightning protection.
Runoff remains a separate environmental and local-rule check. The US EPA notes that storm drains can carry pollution directly to waterways. Remove loose debris first, identify where wash water will go, use chemicals only as directed and follow local water-use, drainage and disposal requirements.
What GoodDayTo cannot measure
The forecast does not know the pressure rating, nozzle angle, hose condition, electrical protection, fuel type, water supply, detergent, drainage, slope, surface material or distance to people and property. It cannot see loose mortar, damaged pointing, old paint, soft timber, seals, roof materials, asbestos-containing material or manufacturer exclusions. Test a discreet area and use specialist advice where damage or contamination is possible.
GoodDayTo also does not know local water restrictions, noise hours, wastewater rules, permissions or whether professional containment is required. The score is deliberately a weather-planning layer—not a claim that pressure washing is appropriate, lawful or safe for the surface.
Frequently asked questions
Can I pressure wash in light rain?
Light rain is not an automatic stop because the job already uses water. GoodDayTo allows a small rain signal, but persistent rain of at least 1 mm across the job or 80% probability in any selected hour caps the result at NOT TODAY.
How do wind and gusts affect the verdict?
Sustained wind of 24 km/h or gusts of 38 km/h prevent GO. Sustained wind of 32 km/h or gusts of 48 km/h cap the result at NOT TODAY. These are conservative planning guardrails, not equipment safety ratings.
Why does cold weather affect pressure washing?
Wet surfaces can dry slowly and may become icy. Air temperature of 5°C or apparent temperature of 3°C prevents GO; 2°C air temperature or 0°C apparent temperature caps the result at NOT TODAY. Follow the machine and detergent instructions if they are stricter.
Does GO mean the surface and machine are safe?
No. GO only describes measured weather fit. Surface strength, nozzle choice, pressure, electrical condition, water supply, drainage, chemicals, people nearby and manufacturer instructions remain separate checks.
Which duration should I choose?
Choose one hour for a small item or area, three hours for an ordinary patio or driveway job, and five hours only for a genuine half-day project. Include setup, treatment and cleanup while you remain exposed.
Can I use a gasoline pressure washer indoors or in a garage?
No. CDC guidance warns that gasoline-powered pressure washers can cause carbon monoxide poisoning and says they should not be used in enclosed or partially enclosed spaces.