As of 15:50 MDT

Weather in Keystone, SD

76°

Keystone, Wednesday, 7 October, 15:50

Mostly clear. Feels like 74°. High 76°, low 45°.

Pressure30.03 inHg

Wind5.6 mph NE

Humidity24%

Visibility6.2 mi

Dew point37°

See detailed hourly forecast

Monthly outlook for Keystone, SD: average high 60°, average low 39.9°. That is 0.5° below the climate normal for October. Precipitation is expected on 3 days (about 0.5 inches), against a normal of 3 days and 0.9 inches. The warmest day looks like 9 October (81.1°), the coolest 17 October (28.3°).

60°/39.9°

Average high / low

−0.5°

Below normal

3 / 3

Wet days / normal

0.5 in

Precipitation this month

Ten-day blocks vs climate normal

Period	Forecast high	Normal	Difference
7 October – 16 October	62.9°	61.4°	+0.8°
17 October – 26 October	55.2°	59°	-2.1°
27 October – 5 November	at normal	52.9°	—

October records over 66 years

90.3°3 October 2025All-time high

-4.2°26 October 2020All-time low

Climate normals and records are computed from the nearest reference point — Hermosa (12 mi).

Thu, 0874° / 42°

74 °

Keystone, Thursday, 8 October

Overcast. High 74°, low 42°.

Pressure29.97 inHg

Wind5.3 mph E

Humidity29%

Visibility6.2 mi

Dew point38°

Fri, 0981° / 49°

81 °

Keystone, Friday, 9 October

Partly cloudy. High 81°, low 49°.

Pressure29.65 inHg

Wind10.4 mph SW

Humidity18%

Visibility6.2 mi

Dew point33°

Sat, 1080° / 58°

0.01

80 °

Keystone, Saturday, 10 October

Light rain. High 80°, low 58°.

Pressure29.50 inHg

Wind10.4 mph SW

Humidity18%

Visibility6.2 mi

Dew point32°

Sun, 1153° / 39°

0.04

53 °

Keystone, Sunday, 11 October

Light rain. High 53°, low 39°.

Pressure29.88 inHg

Wind6.3 mph N

Humidity67%

Visibility6.2 mi

Dew point41°

Mon, 1242° / 35°

0.34

42 °

Keystone, Monday, 12 October

Light rain. High 42°, low 35°.

Pressure30.12 inHg

Wind5.6 mph N

Humidity94%

Visibility—

Dew point36°

Tue, 1375° / 35°

75 °

Keystone, Tuesday, 13 October

Mostly clear. High 75°, low 35°.

Pressure29.80 inHg

Wind17.7 mph S

Humidity38%

Visibility—

Dew point37°

Wed, 1467° / 47°

0.03

67 °

Keystone, Wednesday, 14 October

Light rain. High 67°, low 47°.

Pressure29.50 inHg

Wind19 mph W

Humidity30%

Visibility—

Dew point33°

Thu, 1543° / 34°

0.07

43 °

Keystone, Thursday, 15 October

Snow. High 43°, low 34°.

Pressure30.06 inHg

Wind12.8 mph N

Humidity61%

Visibility—

Dew point27°

Fri, 1639° / 29°

39 °

Keystone, Friday, 16 October

Overcast. High 39°, low 29°.

Pressure30.62 inHg

Wind7.8 mph SE

Humidity58%

Visibility—

Dew point23°

Sat, 1747° / 28°

47 °

Keystone, Saturday, 17 October

Partly cloudy. High 47°, low 28°.

Pressure30.30 inHg

Wind11.3 mph S

Humidity60%

Visibility—

Dew point31°

Sun, 1859° / 41°

59 °

Keystone, Sunday, 18 October

Overcast. High 59°, low 41°.

Pressure29.80 inHg

Wind22.7 mph SW

Humidity49%

Visibility—

Dew point34°

Mon, 1961° / 41°

61 °

Keystone, Monday, 19 October

Partly cloudy. High 61°, low 41°.

Pressure29.88 inHg

Wind20.6 mph SW

Humidity28%

Visibility—

Dew point24°

Tue, 2060° / 39°

60 °

Keystone, Tuesday, 20 October

Partly cloudy. High 60°, low 39°.

Pressure30.18 inHg

Wind12.5 mph E

Humidity29%

Visibility—

Dew point25°

Wed, 2158° / 38°

58 °

Keystone, Wednesday, 21 October

Partly cloudy. High 58°, low 38°.

Pressure30.18 inHg

Wind7.9 mph E

Humidity32%

Visibility—

Dew point25°

Thu, 2247° / 37°

0.04

47 °

Keystone, Thursday, 22 October

Light rain. High 47°, low 37°.

Pressure30.06 inHg

Wind22.7 mph NW

Humidity70%

Visibility—

Dew point33°

From day 17 onward the outlook is built from 60-year climate statistics

Fri, 2357° / 37°

0.04

57 °

Keystone, Friday, 23 October

Climate normal for this date — 60-year average.

Average high57°

Average low37°

Average precipitation0.04 in

Chance of precipitation22%

Record high81° (1973)

Record low6° (1981)

Sat, 2457° / 37°

0.04

57 °

Keystone, Saturday, 24 October

Climate normal for this date — 60-year average.

Average high57°

Average low37°

Average precipitation0.04 in

Chance of precipitation15%

Record high77° (1960)

Record low10° (2002)

Sun, 2558° / 37°

0.02

58 °

Keystone, Sunday, 25 October

Climate normal for this date — 60-year average.

Average high58°

Average low37°

Average precipitation0.02 in

Chance of precipitation10%

Record high78° (2017)

Record low10° (2020)

Mon, 2658° / 37°

0.05

58 °

Keystone, Monday, 26 October

Climate normal for this date — 60-year average.

Average high58°

Average low37°

Average precipitation0.05 in

Chance of precipitation10%

Record high76° (1990)

Record low-4° (2020)

Tue, 2756° / 35°

0.03

56 °

Keystone, Tuesday, 27 October

Climate normal for this date — 60-year average.

Average high56°

Average low35°

Average precipitation0.03 in

Chance of precipitation23%

Record high78° (2016)

Record low8° (2020)

Wed, 2856° / 35°

0.07

56 °

Keystone, Wednesday, 28 October

Climate normal for this date — 60-year average.

Average high56°

Average low35°

Average precipitation0.07 in

Chance of precipitation22%

Record high78° (2016)

Record low13° (1991)

Thu, 2954° / 35°

0.07

54 °

Keystone, Thursday, 29 October

Climate normal for this date — 60-year average.

Average high54°

Average low35°

Average precipitation0.07 in

Chance of precipitation35%

Record high78° (1968)

Record low8° (1991)

Fri, 3052° / 34°

0.04

52 °

Keystone, Friday, 30 October

Climate normal for this date — 60-year average.

Average high52°

Average low34°

Average precipitation0.04 in

Chance of precipitation22%

Record high77° (1968)

Record low3° (1991)

Sat, 3152° / 34°

0.03

52 °

Keystone, Saturday, 31 October

Climate normal for this date — 60-year average.

Average high52°

Average low34°

Average precipitation0.03 in

Chance of precipitation15%

Record high74° (1990)

Record low3° (1991)

Sun, 0151° / 33°

0.05

51 °

Keystone, Sunday, 1 November

Climate normal for this date — 60-year average.

Average high51°

Average low33°

Average precipitation0.05 in

Chance of precipitation18%

Record high72° (1965)

Record low3° (2002)

Mon, 0251° / 32°

0.04

51 °

Keystone, Monday, 2 November

Climate normal for this date — 60-year average.

Average high51°

Average low32°

Average precipitation0.04 in

Chance of precipitation20%

Record high75° (2008)

Record low-2° (1991)

Tue, 0351° / 33°

0.04

51 °

Keystone, Tuesday, 3 November

Climate normal for this date — 60-year average.

Average high51°

Average low33°

Average precipitation0.04 in

Chance of precipitation20%

Record high71° (2020)

Record low2° (1991)

Wed, 0453° / 32°

0.01

53 °

Keystone, Wednesday, 4 November

Climate normal for this date — 60-year average.

Average high53°

Average low32°

Average precipitation0.01 in

Chance of precipitation10%

Record high76° (1978)

Record low7° (1995)

Thu, 0552° / 33°

0.03

52 °

Keystone, Thursday, 5 November

Climate normal for this date — 60-year average.

Average high52°

Average low33°

Average precipitation0.03 in

Chance of precipitation13%

Record high76° (2020)

Record low1° (2003)

About the monthly outlook

How accurate is a 30-day forecast?

The first 16 days come from weather models — reliable for the first 3–5 days and progressively less so after that. Days 17 through 30 for Keystone, SD are built from the climate normal, the 60-year average, so they show typical weather for those dates rather than a specific forecast.

What does "above normal" mean?

We compare the forecast against the climate normal for those exact calendar days, computed from 60 years of observations. The deviation shows how much the coming month differs from a typical one.

Where do the 66-year records come from?

They are real temperature extremes recorded in Keystone, SD since 1960: the highest and lowest reading for each calendar date, with the year it happened.

How often is it updated?

The forecast portion refreshes every hour; the climate portion is based on long-term data and stays stable.