Monthly outlook for Arpan, SD: average high 58.3°, average low 41.1°. That is 0.2° above the climate normal for October. Precipitation is expected on 2 days (about 0.5 inches), against a normal of 3 days and 0.6 inches. The warmest day looks like 20 October (79.3°), the coolest 16 October (30°).
58.3°/41.1°
Average high / low
+0.2°
Above normal
2 / 3
Wet days / normal
0.5 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
13 October – 22 October
60.3°
58.9°
+0.7°
23 October – 1 November
55°
54.4°
+0.4°
2 November – 11 November
at normal
48.6°
—
October records over 66 years
92.5°4 October 1963All-time high
-5.8°26 October 2020All-time low
Wed, 1449° / 41°0.06
49 °
Arpan, Wednesday, 14 October
Light rain. High 49°, low 41°.
Pressure30.18 inHg
Wind6.1 mph SE
Humidity61%
Visibility6.2 mi
Dew point39°
Thu, 1555° / 41°0.02
55 °
Arpan, Thursday, 15 October
Light rain. High 55°, low 41°.
Pressure30.47 inHg
Wind19.2 mph NW
Humidity39%
Visibility6.2 mi
Dew point25°
Fri, 1658° / 30°0
58 °
Arpan, Friday, 16 October
Clear. High 58°, low 30°.
Pressure30.62 inHg
Wind9.9 mph SE
Humidity43%
Visibility6.2 mi
Dew point20°
Sat, 1775° / 38°0
75 °
Arpan, Saturday, 17 October
Partly cloudy. High 75°, low 38°.
Pressure29.97 inHg
Wind8.5 mph W
Humidity24%
Visibility—
Dew point27°
Sun, 1867° / 45°0
67 °
Arpan, Sunday, 18 October
Clear. High 67°, low 45°.
Pressure30.03 inHg
Wind8.6 mph E
Humidity39%
Visibility—
Dew point35°
Mon, 1976° / 45°0
76 °
Arpan, Monday, 19 October
Clear. High 76°, low 45°.
Pressure29.83 inHg
Wind15.4 mph SE
Humidity25%
Visibility—
Dew point27°
Tue, 2079° / 56°0
79 °
Arpan, Tuesday, 20 October
Overcast. High 79°, low 56°.
Pressure29.59 inHg
Wind21.7 mph SW
Humidity23%
Visibility—
Dew point35°
Wed, 2153° / 44°0
53 °
Arpan, Wednesday, 21 October
Overcast. High 53°, low 44°.
Pressure29.94 inHg
Wind13 mph N
Humidity54%
Visibility—
Dew point36°
Thu, 2244° / 37°0.37
44 °
Arpan, Thursday, 22 October
Light rain. High 44°, low 37°.
Pressure29.91 inHg
Wind8.3 mph NW
Humidity88%
Visibility—
Dew point38°
Fri, 2344° / 39°0.04
44 °
Arpan, Friday, 23 October
Light rain. High 44°, low 39°.
Pressure30.09 inHg
Wind21.4 mph W
Humidity82%
Visibility—
Dew point37°
Sat, 2455° / 38°0
55 °
Arpan, Saturday, 24 October
Partly cloudy. High 55°, low 38°.
Pressure30.36 inHg
Wind17.8 mph W
Humidity34%
Visibility—
Dew point22°
Sun, 2554° / 42°0
54 °
Arpan, Sunday, 25 October
Clear. High 54°, low 42°.
Pressure30.36 inHg
Wind21.7 mph NW
Humidity42%
Visibility—
Dew point29°
Mon, 2656° / 36°0
56 °
Arpan, Monday, 26 October
Clear. High 56°, low 36°.
Pressure30.21 inHg
Wind18.7 mph SE
Humidity39%
Visibility—
Dew point24°
Tue, 2769° / 42°0.01
69 °
Arpan, Tuesday, 27 October
Light rain. High 69°, low 42°.
Pressure29.62 inHg
Wind11.4 mph SE
Humidity33%
Visibility—
Dew point32°
Wed, 2852° / 42°0.02
52 °
Arpan, Wednesday, 28 October
Light rain. High 52°, low 42°.
Pressure30.09 inHg
Wind25.4 mph NW
Humidity62%
Visibility—
Dew point32°
From day 17 onward the outlook is built from 60-year climate statistics
Thu, 2953° / 34°0.1
53 °
Arpan, Thursday, 29 October
Climate normal for this date — 60-year average.
Average high53°
Average low34°
Average precipitation0.1 in
Chance of precipitation28%
Record high78° (1968)
Record low3° (1991)
Fri, 3051° / 33°0.03
51 °
Arpan, Friday, 30 October
Climate normal for this date — 60-year average.
Average high51°
Average low33°
Average precipitation0.03 in
Chance of precipitation20%
Record high78° (1968)
Record low-5° (1991)
Sat, 3151° / 33°0.04
51 °
Arpan, Saturday, 31 October
Climate normal for this date — 60-year average.
Average high51°
Average low33°
Average precipitation0.04 in
Chance of precipitation17%
Record high77° (1999)
Record low-2° (1991)
Sun, 0151° / 33°0.06
51 °
Arpan, Sunday, 1 November
Climate normal for this date — 60-year average.
Average high51°
Average low33°
Average precipitation0.06 in
Chance of precipitation17%
Record high74° (1965)
Record low0° (2002)
Mon, 0251° / 32°0.02
51 °
Arpan, Monday, 2 November
Climate normal for this date — 60-year average.
Average high51°
Average low32°
Average precipitation0.02 in
Chance of precipitation20%
Record high75° (1965)
Record low-4° (1991)
Tue, 0350° / 33°0.03
50 °
Arpan, Tuesday, 3 November
Climate normal for this date — 60-year average.
Average high50°
Average low33°
Average precipitation0.03 in
Chance of precipitation17%
Record high72° (2020)
Record low-2° (1991)
Wed, 0452° / 31°0.01
52 °
Arpan, Wednesday, 4 November
Climate normal for this date — 60-year average.
Average high52°
Average low31°
Average precipitation0.01 in
Chance of precipitation12%
Record high78° (1978)
Record low6° (1991)
Thu, 0550° / 32°0.03
50 °
Arpan, Thursday, 5 November
Climate normal for this date — 60-year average.
Average high50°
Average low32°
Average precipitation0.03 in
Chance of precipitation20%
Record high73° (2020)
Record low6° (2003)
Fri, 0650° / 30°0.04
50 °
Arpan, Friday, 6 November
Climate normal for this date — 60-year average.
Average high50°
Average low30°
Average precipitation0.04 in
Chance of precipitation12%
Record high72° (2009)
Record low1° (2003)
Sat, 0750° / 31°0.03
50 °
Arpan, Saturday, 7 November
Climate normal for this date — 60-year average.
Average high50°
Average low31°
Average precipitation0.03 in
Chance of precipitation12%
Record high76° (1999)
Record low-4° (1991)
Sun, 0848° / 30°0.04
48 °
Arpan, Sunday, 8 November
Climate normal for this date — 60-year average.
Average high48°
Average low30°
Average precipitation0.04 in
Chance of precipitation23%
Record high79° (1999)
Record low6° (2000)
Mon, 0945° / 28°0.06
45 °
Arpan, Monday, 9 November
Climate normal for this date — 60-year average.
Average high45°
Average low28°
Average precipitation0.06 in
Chance of precipitation22%
Record high71° (2001)
Record low2° (1966)
Tue, 1046° / 27°0.05
46 °
Arpan, Tuesday, 10 November
Climate normal for this date — 60-year average.
Average high46°
Average low27°
Average precipitation0.05 in
Chance of precipitation20%
Record high71° (2007)
Record low-9° (1986)
Wed, 1144° / 26°0.02
44 °
Arpan, Wednesday, 11 November
Climate normal for this date — 60-year average.
Average high44°
Average low26°
Average precipitation0.02 in
Chance of precipitation17%
Record high68° (2005)
Record low-9° (1986)
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 Arpan, 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 Arpan, 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.