Which is the hottest month in Keystone?

The hottest time of year in Keystone is normally July. Expect maximum daytime temperatures to reach 30°C with moderate heat and humidity.

Which month has the most rain in Keystone?

In terms of rainfall, June is usually the wettest month in Keystone with 92mm on average. There are normally 11 days in June with some rain.

When is it sunniest in Keystone?

The sunniest time of year in Keystone is normally July with bright sunshine on average for 74% of daylight hours; that's 11 hours of sunshine per day.

Best time to visit Keystone

Q: When is the best time to visit Keystone?

The best times to visit Keystone, South Dakota are in June, August and September Maximum daytime temperature = 22 - 30°C. Daily hours of sunshine = 8 hours or more.

The best times to visit Keystone, South Dakota are in June, August and September based on our default weather conditions. Update your weather preferences to see which months best match.

Keystone by month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

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When is the best time to visit Keystone?

The best times to visit Keystone, South Dakota are in June, August and September based on the following average weather conditions.

Maximum daytime temperature = 22 - 30°C [remove]
Daily hours of sunshine = 8 hours or more [remove]

Change the criteria to reflect your weather preferences.

1.5
Jan
2
Feb
2.5
Mar
2.5
Apr
4
May
5
Jun
4.5
Jul
5
Aug
5
Sep
2.5
Oct
1.5
Nov
1.5
Dec

Change criteria

Max Day Temperature (°C)

1
Jan
3
Feb
7
Mar
14
Apr
19
May
25
Jun
29
Jul
28
Aug
23
Sep
16
Oct
7
Nov
2
Dec

Hours of Sunshine (daily)

5
Jan
6
Feb
8
Mar
8
Apr
9
May
10
Jun
11
Jul
10
Aug
9
Sep
7
Oct
5
Nov
5
Dec

Best time to visit

Destination

Daytime temperature

Sunshine hours

Sea temperature

Monthly rainfall

Days with some rain

Heat & humidity

The weather guide for South Dakota (Keystone) shows long term weather averages processed from data supplied by CRU (University of East Anglia) & today's weather forecast provided by meteoblue. Find out more about our data sources.

Metric (°C / mm) | Imperial (°F / inches)