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Outdoor Clothes Drying Calculator

Check whether today's weather is good enough to dry washing outside. Enter a few hourly conditions and the tool estimates drying progress for light, medium and heavy items, plus the best time to bring them in before the weather turns.

Enter drying conditions

Freshly washed clothes are the default. Pick a drier option if they have already been indoors on an airer for a while.

Hour label Temp (°C) Humidity (%) Wind (mph) Condition Action

You can enter from 1 to 12 hours. This is especially useful when the afternoon is bright but rain is expected later.

These values are optional and prefilled with typical figures. Users can overwrite them with their own tariff or dryer data.

Overall verdict Poor outdoor drying conditions overall.
Best general take-in time +4h
Medium item dry by then 59%
Drying hours vs re-wetting hours 5 / 1
Estimated bill saving from air drying £0.40

Thin T-shirt

81%

Partly dry

Expected fully dry time Not fully dry in forecast
Best point reached 90% at +4h

Light jumper

45%

Will still feel damp

Expected fully dry time Not fully dry in forecast
Best point reached 59% at +4h

Heavy jeans

21%

Unlikely to dry outdoors

Expected fully dry time Not fully dry in forecast
Best point reached 41% at +4h

Tumble dryer comparison

Air drying this time should reduce the tumble dryer cost for this load.

Typical full tumble dryer cost £0.68
Air drying this time saves on bills £0.40
Estimated tumble dryer cost still needed £0.28
Estimated dryer time avoided 53 mins
Recommended take-in point +4h
Estimated dryness by then 59%
Dryer type used Vented dryer
Dryer electricity use assumed 2.5 kWh per full cycle
Electricity rate assumed 27.0 p/kWh
By bringing the load in at +4h, the load is around 59% dry, so only the remaining dampness may need tumble drying.

Hourly drying outlook

Hour Conditions Drying quality Thin T-shirt Light jumper Heavy jeans
Now 16.0°C, 62%, 7.0 mph, Bright / sunny intervals Excellent drying hour 19% 12% 9%
+1h 17.0°C, 58%, 8.0 mph, Sunny Excellent drying hour 42% 27% 19%
+2h 17.0°C, 57%, 9.0 mph, Bright / sunny intervals Excellent drying hour 62% 41% 28%
+3h 16.0°C, 60%, 8.0 mph, Cloudy Good drying hour 78% 51% 36%
+4h 15.0°C, 67%, 7.0 mph, Overcast Patchy drying hour 90% 59% 41%
+5h 14.0°C, 75%, 6.0 mph, Drizzle Patchy drying hour 81% 45% 21%

Inputs and assumptions used

Line setup Exposed washing line
Spin level High spin / well wrung out
Starting dryness Freshly washed
Forecast hours entered 6
End-of-window result for medium item 45%
Best general take-in time +4h
A simple rule of thumb: if later forecast rows include drizzle or rain, use the best take-in time instead of leaving clothes out for the full period.

How to read this estimate

  • This is a practical estimate rather than a meteorological model. It balances ease of use with a sensible drying forecast for common UK conditions.
  • Drying is helped by warmer air, lower humidity, more wind and more sunshine. Rain or drizzle can reverse progress, especially on exposed lines.
  • The three garments are proxies for small, medium and heavy items. Bedding, towels and thick cotton hoodies can behave more like or slower than the heavy jeans example.
  • The best take-in time is based on the medium item, so it is a good general signal for mixed loads when later hours start getting worse.
  • The tumble dryer comparison is a practical estimate. It assumes the remaining dryer cost scales roughly with how much moisture is left in the load.

What this clothes drying calculator does

This calculator estimates how outdoor weather affects drying for a small item, a medium item and a heavier item. It uses hourly temperature, humidity, wind and weather condition inputs to model whether clothes are likely to dry, how much progress they make, and whether later rain or drizzle could undo some of that drying.

Why humidity matters as much as temperature

Warm weather helps, but humidity often decides whether laundry dries quickly or just feels clammy. A breezy 15°C afternoon with lower humidity can dry clothes better than a humid 20°C spell with little airflow. That is why the calculator looks at several factors together instead of temperature alone.

How to use it well

  • Add up to 12 forecast hours if you want to reflect the afternoon improving or evening rain arriving.
  • Use the line setup to reflect whether rain can reach the clothes easily.
  • Choose the spin level honestly, because badly spun clothes take much longer to finish drying.
  • Use the medium or heavy item result if your load is mostly sweatshirts, joggers, towels or jeans.

Important note

This is a planning estimate, not a guarantee. Real drying speed depends on fabric type, item thickness, how spaced out the clothes are on the line, direct sunshine angle, shade from buildings, and whether rain showers are heavier or lighter than expected.