Soapstone Prairie Natural Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Soapstone Prairie Natural Area clear sky chart from 2005-11-05 to 2017-09-19.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.
Observation TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(no limit)Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
44%
16001
25%
46885
14%
15956
55%
15956
35%
26088

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 15thNight
27%
899
28%
2506
9%
895
44%
895
32%
1335
January16th to endNight
25%
840
31%
2568
10%
840
47%
840
31%
1311
February1st to 15thNight
22%
702
24%
2264
6%
699
44%
699
27%
1206
February16th to endNight
24%
632
28%
1894
9%
632
44%
632
29%
1069
March1st to 15thNight
34%
720
24%
2121
10%
720
47%
720
35%
1176
March16th to endNight
36%
677
22%
2021
11%
677
47%
677
31%
1177
April1st to 15thNight
35%
539
21%
1798
12%
539
50%
539
27%
1022
April16th to endNight
36%
540
21%
1800
14%
540
48%
540
26%
1088
May1st to 15thNight
44%
540
19%
1551
14%
540
50%
540
27%
991
May16th to endNight
49%
563
17%
1498
12%
561
54%
561
32%
961
June1st to 15thNight
61%
540
18%
1440
12%
540
64%
540
40%
839
June16th to endNight
69%
540
26%
1440
19%
540
73%
540
57%
722
July1st to 15thNight
73%
510
18%
1360
15%
510
74%
510
40%
798
July16th to endNight
77%
564
25%
1416
22%
531
78%
531
46%
791
August1st to 15thNight
74%
539
21%
1639
20%
536
75%
536
38%
905
August16th to endNight
73%
573
29%
1910
32%
573
76%
573
40%
999
September1st to 15thNight
65%
540
26%
1800
24%
540
73%
540
37%
960
September16th to endNight
65%
504
36%
1809
33%
504
73%
504
46%
834
October1st to 15thNight
46%
654
26%
1974
15%
654
55%
654
33%
1146
October16th to endNight
45%
750
32%
2158
14%
750
57%
750
41%
1142
November1st to 15thNight
43%
875
29%
2275
13%
875
53%
875
43%
1265
November16th to endNight
37%
900
32%
2435
11%
900
54%
900
42%
1287
December1st to 15thNight
24%
900
20%
2520
5%
900
38%
900
28%
1481
December16th to endNight
28%
960
25%
2688
7%
960
44%
960
29%
1583

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

Occurrence of each ForecastData
Points
Cloud CoverDay
6%5%244245%6%7%50%
47948
Night
5%5%2432345%7%56%
47057
TransparencyDay
30%7%12%24%18%6%
47622
Night
26%5%13%27%20%6%
46885
SeeingDay
10%10%28%28%16%4
5923
Night
7%13%29%33%14%1
16004

By Month

Percentage Cloud Cover SW (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
15%25%42335%8%56%
1432
16th to endDay
15%2442335%6%61%
1665
February1st to 15thDay
6%27%42445%8%53%
1596
16th to endDay
17%25%5%2345%7%55%
1580
March1st to 15thDay
3435%42346%7%54%
1838
16th to endDay
5%6%245%245%6%7%47%
2202
April1st to 15thDay
7%6%25%3235%6%7%48%
2150
16th to endDay
11%9%25%5%35%5%47%38%
2160
May1st to 15thDay
15%7%25%425%5%6%7%37%
2398
16th to endDay
12%6%245%36%6%6%7%36%
2616
June1st to 15thDay
8%414426%6%7%9%44%
2520
16th to endDay
3213325%7%6%8%56%
2520
July1st to 15thDay
7%4145%25%6%6%8%46%
2520
16th to endDay
4325%5%37%7%7%9%44%
2656
August1st to 15thDay
6%425%5%45%6%7%9%43%
2309
16th to endDay
6%3145%25%5%6%7%52%
2292
September1st to 15thDay
9%4123245%5%6%53%
2160
16th to endDay
4313224446%62%
1896
October1st to 15thDay
8%5%13423445%55%
1653
16th to endDay
6%5%13313246%61%
1702
November1st to 15thDay
2423324449%56%
1583
16th to endDay
143232346%9%57%
1524
December1st to 15thDay
25%36%42335%7%53%
1440
16th to endDay
26%35%42445%6%54%
1536
January1st to 15thNight
232441335%7%61%
2506
16th to endNight
25%23323346%63%
2568
February1st to 15thNight
26%34413348%58%
2254
16th to endNight
29%34423336%56%
1894
March1st to 15thNight
25%25%424348%55%
2121
16th to endNight
6%5%133245%5%8%51%
2021
April1st to 15thNight
7%7%2432445%6%51%
1798
16th to endNight
13%7%23324437%47%
1800
May1st to 15thNight
14%6%1433345%8%44%
1550
16th to endNight
11%5%1432445%8%46%
1497
June1st to 15thNight
6%3133245%6%9%53%
1440
16th to endNight
41211335%7%68%
1440
July1st to 15thNight
6%314225%5%6%8%52%
1440
16th to endNight
321342447%8%56%
1512
August1st to 15thNight
5%313425%6%6%9%52%
1647
16th to endNight
6%314424447%57%
1910
September1st to 15thNight
10%41322235%6%57%
1800
16th to endNight
5%312223336%65%
1809
October1st to 15thNight
10%5%1332235%5%55%
1974
16th to endNight
6%5%12223347%60%
2158
November1st to 15thNight
3313423447%62%
2275
16th to endNight
242331336%7%61%
2435
December1st to 15thNight
26%35%42345%7%54%
2520
16th to endNight
36%3432346%7%53%
2688

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
25%6%16%31%17%3
1433
16th to endDay
24%314%32%20%4
1665
February1st to 15thDay
28%8%17%32%9%3
1597
16th to endDay
28%413%32%17%4
1580
March1st to 15thDay
27%415%27%20%4
1838
16th to endDay
33%5%14%26%16%3
2202
April1st to 15thDay
32%7%14%24%15%6%
2150
16th to endDay
43%6%11%22%12%3
2160
May1st to 15thDay
42%8%12%20%14%1
2398
16th to endDay
41%9%12%19%13%2
2620
June1st to 15thDay
30%10%14%20%18%6%
2520
16th to endDay
21%7%10%25%21%14%
2520
July1st to 15thDay
32%8%12%18%15%13%
2371
16th to endDay
29%10%11%22%17%8%
2489
August1st to 15thDay
32%9%12%19%14%11%
2293
16th to endDay
27%7%10%20%24%9%
2292
September1st to 15thDay
27%6%8%21%23%12%
2160
16th to endDay
21%5%8%27%31%5%
1896
October1st to 15thDay
29%7%10%23%23%6%
1653
16th to endDay
23%5%9%28%25%6%
1702
November1st to 15thDay
24%6%12%25%22%8%
1583
16th to endDay
22%5%12%30%23%5%
1524
December1st to 15thDay
29%5%16%33%13%1
1440
16th to endDay
30%5%16%25%17%3
1536
January1st to 15thNight
21%5%17%29%20%4
2506
16th to endNight
22%414%30%22%5%
2568
February1st to 15thNight
27%417%34%13%3
2264
16th to endNight
29%411%28%21%5%
1894
March1st to 15thNight
27%413%27%21%4
2121
16th to endNight
29%6%14%27%19%2
2021
April1st to 15thNight
31%6%13%28%15%5%
1798
16th to endNight
37%5%10%26%17%2
1800
May1st to 15thNight
38%6%13%25%15%1
1551
16th to endNight
33%8%18%22%13%3
1498
June1st to 15thNight
25%8%19%22%15%8%
1440
16th to endNight
16%412%29%23%13%
1440
July1st to 15thNight
27%7%13%25%17%9%
1360
16th to endNight
21%8%14%30%16%9%
1416
August1st to 15thNight
25%7%16%21%18%9%
1639
16th to endNight
25%5%9%26%22%10%
1910
September1st to 15thNight
27%5%12%19%20%14%
1800
16th to endNight
19%47%31%31%5%
1809
October1st to 15thNight
30%5%11%20%24%6%
1974
16th to endNight
24%310%28%24%7%
2158
November1st to 15thNight
22%413%23%26%9%
2275
16th to endNight
21%411%30%25%6%
2435
December1st to 15thNight
29%6%17%29%14%3
2520
16th to endNight
28%7%16%29%16%1
2688

Seeing (when cloud cover <= 80%)
Color Meanings:
Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
10%14%35%23%13%3
90
16th to endDay
8%31%29%19%10%1
96
February1st to 15thDay
11%32%38%15%2
90
16th to endDay
6%25%34%28%4
81
March1st to 15thDay
10%25%31%24%7%
128
16th to endDay
12%21%42%20%2
288
April1st to 15thDay
12%27%36%17%5%1
269
16th to endDay
25%23%30%14%41
270
May1st to 15thDay
18%11%29%23%12%4
447
16th to endDay
16%9%29%23%17%4
517
June1st to 15thDay
10%5%25%30%22%5%
495
16th to endDay
2332%33%21%6%
495
July1st to 15thDay
10%217%35%26%8%
475
16th to endDay
5%118%35%30%8%
515
August1st to 15thDay
9%323%42%17%3
321
16th to endDay
6%325%40%19%4
332
September1st to 15thDay
10%5%34%28%16%3
315
16th to endDay
6%5%30%29%17%9%
147
October1st to 15thDay
10%5%28%31%21%3
90
16th to endDay
11%9%32%28%16%2
96
November1st to 15thDay
48%26%30%17%12%
90
16th to endDay
17%22%32%24%3
90
December1st to 15thDay
7%30%38%20%3
90
16th to endDay
426%39%25%5%
96
January1st to 15thNight
5%27%35%22%7%2
900
16th to endNight
5%26%37%23%5%
840
February1st to 15thNight
5%23%41%24%4
704
16th to endNight
7%22%40%26%4
632
March1st to 15thNight
416%40%30%7%1
720
16th to endNight
8%15%36%30%8%
677
April1st to 15thNight
10%14%34%32%7%
539
16th to endNight
19%11%29%29%8%1
540
May1st to 15thNight
17%8%23%34%14%1
540
16th to endNight
13%425%33%20%1
563
June1st to 15thNight
8%422%46%16%1
540
16th to endNight
3219%50%21%1
540
July1st to 15thNight
7%110%42%34%4
510
16th to endNight
48%40%42%3
564
August1st to 15thNight
6%110%46%31%3
539
16th to endNight
5%19%42%36%3
573
September1st to 15thNight
11%215%38%26%5%
540
16th to endNight
5%5%20%39%25%3
504
October1st to 15thNight
11%10%26%31%15%3
654
16th to endNight
9%12%30%34%11%2
750
November1st to 15thNight
6%12%33%34%10%2
875
16th to endNight
5%16%36%32%7%
900
December1st to 15thNight
5%23%39%24%5%1
900
16th to endNight
6%20%38%27%6%
960
Page generated at 2017-09-20 02:49:56. Version ac04

Copyright 2017 A. Danko


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