See exactly when rain will start and stop with a minute-by-minute precipitation nowcast for the next hour.
Compare today's weather with yesterday's data and track temperature trends over time.
Hourly Forecast
Daylight Hours
07:35
Sunrise
19:13
Sunset
Moon
Waning Gibbous
19:24
Moonrise
08:17
Moonset
Daily Forecast
Today
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
Monday
Tuesday
Air Quality Data Available
Upgrade to access real-time air quality data for Grignon.
Resources
UV Index
Humidity
Current stargazing conditions?
See sky darkness, moon phase, and the best viewing window for Grignon.
View stargazing scoreWeather in Grignon today, September 27, 2026
Grignon starts September 27, 2026 under largely sunny skies, with bright spells setting the tone from the outset. Outdoor plans should enjoy long stretches of open sky as the day unfolds. The morning looks comparatively open, with cloud near 0% around 05:00. Early outdoor plans have a better chance of staying dry and bright.
The day peaks near 28°C and cools toward 17°C. Relative humidity sits between 34% and 51%, reaching its peak around 10:00. A lighter breeze peaks around 22:00 near 1.3 km/h.
Expect persistent cloud later on, with amounts around 65% by 19:00. Sunshine remains the exception, not the rule. Visibility stays generally good near 43.9 km on average, though it can drop toward 41.8 km in thicker cloud or showers. Sunrise is at 07:35 and sunset at 19:13, giving 11 hours 38 minutes of sunlight today.
Overall, Grignon on September 27, 2026 favours outdoor plans under mostly open skies, with a comfortable high near 28°C.
Frequently asked questions about weather in Grignon
How warm does it get in Grignon?
The warmest month in Grignon is July, with average high temperatures of 21°C. The average temperature during this period is around 16°C.
How cold does it get in Grignon?
The coldest month in Grignon is January, with average low temperatures of -8°C. The average temperature during this period is around -4°C.
What is the wettest time of year in Grignon?
The wettest month in Grignon is December, with an average of 197mm of precipitation.
What is the driest time of year in Grignon?
The driest month in Grignon is August, with an average of 95mm of precipitation.
Explore more weather forecasts
- Albertville, Auvergne-Rhône-Alpes
- Paris, Île-de-France
- Seynod, Auvergne-Rhône-Alpes
- Marseille, Provence-Alpes-Côte d'Azur
- Annecy, Auvergne-Rhône-Alpes
- Lyon, Auvergne-Rhône-Alpes
- Annecy-le-Vieux, Auvergne-Rhône-Alpes
- Toulouse, Occitanie
- Cran-Gevrier, Auvergne-Rhône-Alpes
- Nice, Provence-Alpes-Côte d'Azur
- Aix-les-Bains, Auvergne-Rhône-Alpes
- Nantes, Pays de la Loire
- Chambéry, Auvergne-Rhône-Alpes
- Marne La Vallée, Île-de-France
- Sallanches, Auvergne-Rhône-Alpes
- Strasbourg, Grand Est
