Climate Insights for Green Valley

Mellette County, California, United States

Hottest
September
30°C peak
Coldest
December
6°C low
Wettest
January
153mm rain
Best to Visit
April, May, June
Mild temps & low rain

Climate Overview

The climate in Green Valley is temperate. The average annual temperature is 16°C and approximately 564mm of precipitation falls per year. January is the wettest month, receiving around 153mm of rainfall. Green Valley is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: September, July, June. The coldest months are December, January, February, when temperatures can drop to 6°C.

Temperature

10° 15° 20° 25° 30° Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Max: 15° Average: 10° Min: 7° Feb Max: 18° Average: 12° Min: 7° Mar Max: 19° Average: 13° Min: 8° Apr Max: 23° Average: 16° Min: 10° May Max: 25° Average: 18° Min: 12° Jun Max: 30° Average: 21° Min: 14° Jul Max: 30° Average: 21° Min: 14° Aug Max: 30° Average: 21° Min: 15° Sep Max: 30° Average: 21° Min: 14° Oct Max: 27° Average: 18° Min: 11° Nov Max: 20° Average: 13° Min: 8° Dec Max: 16° Average: 10° Min: 6°
Max
Average
Min

Temperatures in Green Valley vary considerably across the year, with a 24°C difference between the coldest and warmest months. The warmest month is September, when average highs reach 30°C and the mean temperature sits around 21°C. December is the coolest month, with minimum temperatures around 6°C and an average of 10°C. On average, daily temperatures fluctuate by about 13°C between overnight lows and afternoon highs. The sharpest temperature change occurs between October and November, with a 5°C shift in average temperatures.

Precipitation

0mm 50mm 100mm 150mm 200mm Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Precipitation: 153mm Feb Precipitation: 104mm Mar Precipitation: 103mm Apr Precipitation: 38mm May Precipitation: 23mm Jun Precipitation: 2mm Jul Precipitation: 0mm Aug Precipitation: 0mm Sep Precipitation: 1mm Oct Precipitation: 22mm Nov Precipitation: 46mm Dec Precipitation: 72mm
Precipitation

Green Valley is a relatively dry area, receiving approximately 564mm of precipitation annually, which averages out to around 47mm per month. The wettest month is January, averaging 153mm of rainfall. February and March also tend to see above-average precipitation. The driest month is July, with just 0mm. That's 153mm less than January, the wettest month. Rainfall is heavily concentrated in certain months, creating a distinct wet and dry season. Visitors should plan around these patterns, as the difference between peak and low months is dramatic.

Wind

0km/h 5km/h Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Wind Speed: 2km/h Feb Wind Speed: 2km/h Mar Wind Speed: 2km/h Apr Wind Speed: 3km/h May Wind Speed: 3km/h Jun Wind Speed: 3km/h Jul Wind Speed: 3km/h Aug Wind Speed: 3km/h Sep Wind Speed: 2km/h Oct Wind Speed: 2km/h Nov Wind Speed: 2km/h Dec Wind Speed: 2km/h
Wind Speed

Green Valley is relatively calm, with an average annual wind speed of 3km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is July, averaging 3km/h, though still comfortable for most outdoor activities. The calmest conditions occur in November, with average winds dropping to 2km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 1km/h gap between the calmest and windiest months.

Seasons

Winter
Dec 21
Spring
Mar 20
Summer
Jun 21
Autumn
Sep 23

7 days until Summer

It is currently spring in Green Valley, which began on March 20, 2026. Green Valley is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in September at around 30°C, while the coldest stretch bottoms out in December near 6°C. Summer is next, beginning on June 21, 2026 — 7 days from now.

Spring

Temperatures range from 8 to 25°C. Precipitation is moderate at around 164mm for the season, averaging 55mm per month. Winds are generally light, averaging 3km/h. Light layers work well as temperatures warm through the season — a great time to be outdoors.

Summer

Temperatures range from 14 to 30°C. Precipitation is minimal, with only around 2mm for the entire season. Winds are generally light, averaging 3km/h. Light, breathable clothing is ideal — perfect conditions for outdoor activities.

Autumn

Temperatures range from 8 to 30°C. Rainfall is relatively light, with around 69mm over the season and a monthly average of 23mm. Winds are generally light, averaging 2km/h. Layered clothing works best as temperatures gradually cool — enjoy the crisp air and changing scenery.

Winter

Temperatures range from 6 to 18°C. Rainfall is heavy, totalling around 330mm across the season with a monthly average of 110mm. Winds are generally light, averaging 2km/h. A light jacket or sweater is usually sufficient, though cooler evenings may call for an extra layer.

Best Time to Visit

Jan 10°
Feb 12°
Mar 13°
Apr 16°
May 18°
Jun 21°
Jul 21°
Aug 21°
Sep 21°
Oct 18°
Nov 13°
Dec 10°

The best time to visit Green Valley is during April, May, June, July, August, September and October, when the weather is most comfortable for travellers. During these months, average temperatures hover around 19°C with modest rainfall averaging 12mm per month. By contrast, December can be quite cold with temperatures dropping to 6°C. With minimal rainfall expected, you can pack light and plan outdoor activities with confidence.

Monthly Climate Data

The table below shows monthly climate averages for Green Valley based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.

Month
Min Temperature
Max Temperature
Wind Speed
Precipitation
Snow
Jan
7 °C
15 °C
2 km/h
153 mm
0 cm
Feb
7 °C
18 °C
2 km/h
104 mm
0 cm
Mar
8 °C
19 °C
2 km/h
103 mm
0 cm
Apr
10 °C
23 °C
3 km/h
38 mm
0 cm
May
12 °C
25 °C
3 km/h
23 mm
0 cm
Jun Current
14 °C
30 °C
3 km/h
2 mm
0 cm
Jul
14 °C
30 °C
3 km/h
0 mm
0 cm
Aug
15 °C
30 °C
3 km/h
0 mm
0 cm
Sep
14 °C
30 °C
2 km/h
1 mm
0 cm
Oct
11 °C
27 °C
2 km/h
22 mm
0 cm
Nov
8 °C
20 °C
2 km/h
46 mm
0 cm
Dec
6 °C
16 °C
2 km/h
72 mm
0 cm
Airpult

Get accurate weather forecasts worldwide with real-time updates and severe weather alerts. Covering 6M+ locations with precise, reliable weather data.

© 2026 Samuenti GmbH. All rights reserved.

gb English
Metric (°C, km/h)

Confirm