Monthly outlook for Arpan, SD: average high 63.9°, average low 45.5°. That is 2.9° above the climate normal for October. Precipitation is expected on 2 days (about 0.4 inches), against a normal of 3 days and 0.7 inches. The warmest day looks like 19 October (75.1°), the coolest 16 October (34.4°).
63.9°/45.5°
Average high / low
+2.9°
Above normal
2 / 3
Wet days / normal
0.4 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
11 October – 20 October
62.3°
59.4°
+1.6°
21 October – 30 October
66.5°
55.8°
+5.9°
31 October – 9 November
at normal
49.9°
—
October records over 66 years
92.5°4 October 1963All-time high
-5.8°26 October 2020All-time low
Mon, 1254° / 45°0
54 °
Arpan, Monday, 12 October
Light rain. High 54°, low 45°.
Pressure29.88 inHg
Wind20.5 mph NW
Humidity70%
Visibility6.2 mi
Dew point42°
Tue, 1351° / 42°0.17
51 °
Arpan, Tuesday, 13 October
Rain. High 51°, low 42°.
Pressure30.09 inHg
Wind2.7 mph E
Humidity69%
Visibility6.2 mi
Dew point38°
Wed, 1454° / 46°0.03
54 °
Arpan, Wednesday, 14 October
Light rain. High 54°, low 46°.
Pressure30.21 inHg
Wind5.8 mph SE
Humidity50%
Visibility6.2 mi
Dew point36°
Thu, 1561° / 46°0.19
61 °
Arpan, Thursday, 15 October
Rain. High 61°, low 46°.
Pressure30.39 inHg
Wind19.4 mph NW
Humidity39%
Visibility—
Dew point33°
Fri, 1662° / 34°0
62 °
Arpan, Friday, 16 October
Clear. High 62°, low 34°.
Pressure30.56 inHg
Wind11.5 mph SE
Humidity42%
Visibility—
Dew point29°
Sat, 1770° / 38°0
70 °
Arpan, Saturday, 17 October
Clear. High 70°, low 38°.
Pressure30.03 inHg
Wind7.9 mph SE
Humidity25%
Visibility—
Dew point22°
Sun, 1871° / 54°0
71 °
Arpan, Sunday, 18 October
Overcast. High 71°, low 54°.
Pressure30.00 inHg
Wind13.2 mph NW
Humidity26%
Visibility—
Dew point31°
Mon, 1975° / 50°0
75 °
Arpan, Monday, 19 October
Overcast. High 75°, low 50°.
Pressure29.88 inHg
Wind11.3 mph SE
Humidity27%
Visibility—
Dew point31°
Tue, 2067° / 53°0
67 °
Arpan, Tuesday, 20 October
Clear. High 67°, low 53°.
Pressure29.74 inHg
Wind21.4 mph NW
Humidity29%
Visibility—
Dew point32°
Wed, 2167° / 45°0
67 °
Arpan, Wednesday, 21 October
Clear. High 67°, low 45°.
Pressure29.97 inHg
Wind9.4 mph W
Humidity34%
Visibility—
Dew point32°
Thu, 2267° / 46°0
67 °
Arpan, Thursday, 22 October
Overcast. High 67°, low 46°.
Pressure30.03 inHg
Wind5.4 mph NE
Humidity34%
Visibility—
Dew point32°
Fri, 2373° / 45°0
73 °
Arpan, Friday, 23 October
Clear. High 73°, low 45°.
Pressure30.06 inHg
Wind13.9 mph E
Humidity25%
Visibility—
Dew point28°
Sat, 2469° / 51°0
69 °
Arpan, Saturday, 24 October
Clear. High 69°, low 51°.
Pressure30.06 inHg
Wind13.6 mph W
Humidity17%
Visibility—
Dew point18°
Sun, 2558° / 45°0
58 °
Arpan, Sunday, 25 October
Mostly clear. High 58°, low 45°.
Pressure30.33 inHg
Wind15.1 mph NW
Humidity31%
Visibility—
Dew point24°
Mon, 2665° / 37°0
65 °
Arpan, Monday, 26 October
Overcast. High 65°, low 37°.
Pressure30.00 inHg
Wind10.1 mph SE
Humidity25%
Visibility—
Dew point19°
From day 17 onward the outlook is built from 60-year climate statistics
Tue, 2755° / 35°0.03
55 °
Arpan, Tuesday, 27 October
Climate normal for this date — 60-year average.
Average high55°
Average low35°
Average precipitation0.03 in
Chance of precipitation23%
Record high77° (2016)
Record low9° (2020)
Wed, 2855° / 35°0.05
55 °
Arpan, Wednesday, 28 October
Climate normal for this date — 60-year average.
Average high55°
Average low35°
Average precipitation0.05 in
Chance of precipitation18%
Record high80° (1985)
Record low13° (1991)
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)
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.