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 2018-10-27.

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%
17481
26%
51262
14%
17436
55%
17436
35%
28468

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%
974
28%
2716
9%
970
43%
970
32%
1455
January16th to endNight
26%
910
32%
2782
11%
910
48%
910
32%
1414
February1st to 15thNight
22%
762
24%
2457
6%
759
43%
759
27%
1307
February16th to endNight
25%
684
28%
2050
9%
684
45%
684
29%
1155
March1st to 15thNight
36%
780
26%
2298
11%
780
49%
780
36%
1248
March16th to endNight
36%
733
22%
2189
10%
733
47%
733
31%
1277
April1st to 15thNight
35%
584
21%
1948
12%
584
49%
584
27%
1112
April16th to endNight
37%
579
21%
1929
14%
579
49%
579
26%
1160
May1st to 15thNight
45%
585
19%
1681
14%
585
51%
585
27%
1076
May16th to endNight
50%
611
17%
1626
12%
609
54%
609
32%
1039
June1st to 15thNight
61%
585
20%
1560
13%
585
65%
585
41%
892
June16th to endNight
68%
585
25%
1560
18%
585
71%
585
55%
802
July1st to 15thNight
74%
555
19%
1480
17%
555
75%
555
42%
855
July16th to endNight
77%
612
24%
1544
22%
579
78%
579
46%
864
August1st to 15thNight
74%
575
22%
1748
21%
572
75%
572
39%
957
August16th to endNight
72%
621
28%
2070
31%
621
75%
621
39%
1088
September1st to 15thNight
66%
585
28%
1950
26%
585
74%
585
38%
1030
September16th to endNight
63%
582
34%
2093
31%
582
71%
582
42%
999
October1st to 15thNight
46%
773
26%
2333
14%
773
55%
773
32%
1369
October16th to endNight
44%
866
34%
2498
14%
866
57%
866
41%
1309
November1st to 15thNight
44%
950
29%
2470
13%
950
53%
950
43%
1377
November16th to endNight
37%
975
32%
2638
11%
975
53%
975
42%
1390
December1st to 15thNight
24%
975
21%
2730
5%
975
39%
975
29%
1571
December16th to endNight
28%
1040
25%
2912
8%
1040
44%
1040
29%
1722

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%
52309
Night
5%5%2432345%7%56%
51434
TransparencyDay
29%7%12%24%18%6%
51983
Night
26%5%13%27%20%6%
51262
SeeingDay
10%11%29%28%15%4
7387
Night
7%13%29%33%14%1
17484

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%35%42335%8%55%
1552
16th to endDay
15%2442235%7%60%
1804
February1st to 15thDay
16%27%42445%8%53%
1733
16th to endDay
17%25%5%2335%6%56%
1710
March1st to 15thDay
3425%42336%7%56%
1991
16th to endDay
5%6%245%25%5%6%7%47%
2386
April1st to 15thDay
7%6%25%3235%6%7%49%
2330
16th to endDay
11%9%25%435%5%5%7%39%
2306
May1st to 15thDay
15%7%25%5%25%5%6%8%36%
2598
16th to endDay
12%6%245%36%6%7%7%37%
2840
June1st to 15thDay
7%414326%6%7%9%45%
2730
16th to endDay
3213325%7%6%8%55%
2730
July1st to 15thDay
7%4145%25%6%7%8%46%
2730
16th to endDay
43245%36%7%7%9%44%
2880
August1st to 15thDay
6%425%5%45%6%7%9%43%
2453
16th to endDay
5%3145%25%5%6%7%51%
2484
September1st to 15thDay
9%4123245%6%6%53%
2340
16th to endDay
6%413233446%60%
2197
October1st to 15thDay
9%6%13423445%53%
1953
16th to endDay
5%5%13313346%62%
1969
November1st to 15thDay
2423324449%56%
1718
16th to endDay
133232346%9%57%
1651
December1st to 15thDay
25%35%42335%7%55%
1560
16th to endDay
25%35%42445%6%55%
1664
January1st to 15thNight
232441345%7%61%
2716
16th to endNight
2423323346%63%
2782
February1st to 15thNight
26%35%413348%58%
2447
16th to endNight
28%34423336%56%
2050
March1st to 15thNight
2424324348%57%
2298
16th to endNight
6%6%2432445%8%51%
2189
April1st to 15thNight
7%7%2432445%6%50%
1948
16th to endNight
13%7%23323437%47%
1929
May1st to 15thNight
15%6%1332345%8%43%
1680
16th to endNight
11%5%1432445%8%46%
1625
June1st to 15thNight
6%31332446%9%55%
1560
16th to endNight
5%1311335%7%66%
1560
July1st to 15thNight
6%313225%5%6%8%54%
1560
16th to endNight
32134245%7%8%56%
1640
August1st to 15thNight
4313425%5%6%9%53%
1756
16th to endNight
6%314324447%56%
2070
September1st to 15thNight
9%41322235%6%58%
1950
16th to endNight
6%313223336%63%
2093
October1st to 15thNight
11%6%13322345%54%
2333
16th to endNight
6%5%13223346%62%
2498
November1st to 15thNight
331342345%7%61%
2470
16th to endNight
241331336%7%61%
2638
December1st to 15thNight
25%25%423447%56%
2730
16th to endNight
36%3442345%7%53%
2912

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
26%5%16%29%17%3
1553
16th to endDay
24%415%31%20%4
1804
February1st to 15thDay
28%8%18%31%10%3
1734
16th to endDay
28%312%32%18%4
1710
March1st to 15thDay
26%414%27%22%5%
1991
16th to endDay
33%6%14%26%15%3
2386
April1st to 15thDay
31%7%14%25%14%6%
2330
16th to endDay
41%7%11%23%13%2
2306
May1st to 15thDay
43%8%12%20%14%1
2598
16th to endDay
40%9%12%20%13%2
2844
June1st to 15thDay
29%10%13%20%18%8%
2730
16th to endDay
22%7%10%24%20%14%
2730
July1st to 15thDay
30%8%12%18%17%12%
2581
16th to endDay
28%10%12%22%17%8%
2713
August1st to 15thDay
32%9%12%19%14%11%
2437
16th to endDay
27%8%10%20%24%9%
2484
September1st to 15thDay
27%6%8%20%22%13%
2340
16th to endDay
24%5%8%25%31%6%
2197
October1st to 15thDay
31%6%9%22%24%6%
1953
16th to endDay
22%5%9%29%25%7%
1969
November1st to 15thDay
24%5%12%26%22%7%
1718
16th to endDay
21%5%12%30%25%5%
1651
December1st to 15thDay
27%5%15%33%15%2
1560
16th to endDay
30%5%15%26%18%3
1664
January1st to 15thNight
22%5%17%29%20%4
2716
16th to endNight
22%414%30%22%5%
2782
February1st to 15thNight
27%418%33%13%3
2457
16th to endNight
29%411%27%22%4
2050
March1st to 15thNight
25%413%27%24%4
2298
16th to endNight
30%6%14%27%18%2
2189
April1st to 15thNight
32%5%13%28%14%4
1948
16th to endNight
36%5%10%26%18%2
1929
May1st to 15thNight
38%6%13%25%14%1
1681
16th to endNight
33%8%18%22%13%2
1626
June1st to 15thNight
23%8%18%22%17%9%
1560
16th to endNight
17%412%28%23%13%
1560
July1st to 15thNight
25%7%13%25%18%9%
1480
16th to endNight
21%8%14%29%16%8%
1544
August1st to 15thNight
25%7%16%23%17%9%
1748
16th to endNight
25%5%10%26%21%10%
2070
September1st to 15thNight
26%5%12%19%20%15%
1950
16th to endNight
21%47%29%29%7%
2093
October1st to 15thNight
32%5%11%20%23%6%
2333
16th to endNight
23%311%27%25%8%
2498
November1st to 15thNight
23%413%24%25%8%
2470
16th to endNight
20%412%30%24%6%
2638
December1st to 15thNight
27%6%16%28%16%4
2730
16th to endNight
29%7%16%28%16%2
2912

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
8%13%40%23%11%2
135
16th to endDay
5%30%32%20%9%
144
February1st to 15thDay
11%31%39%15%1
135
16th to endDay
5%27%36%27%3
120
March1st to 15thDay
8%25%30%26%7%1
176
16th to endDay
12%22%42%19%3
352
April1st to 15thDay
12%28%36%17%4
329
16th to endDay
24%21%29%18%5%1
318
May1st to 15thDay
19%10%27%24%13%4
520
16th to endDay
15%8%28%23%18%4
597
June1st to 15thDay
9%5%27%31%21%5%
570
16th to endDay
4431%33%20%5%
570
July1st to 15thDay
9%216%35%27%8%
550
16th to endDay
6%120%35%29%8%
595
August1st to 15thDay
9%324%41%16%4
366
16th to endDay
6%5%27%38%18%4
396
September1st to 15thDay
9%5%32%30%18%4
375
16th to endDay
12%433%26%15%6%
232
October1st to 15thDay
17%8%30%27%12%2
180
16th to endDay
6%13%34%28%12%3
178
November1st to 15thDay
5%9%28%32%14%8%
135
16th to endDay
11%23%36%25%2
135
December1st to 15thDay
5%37%34%21%2
135
16th to endDay
425%43%22%3
144
January1st to 15thNight
5%26%35%23%7%2
975
16th to endNight
5%25%37%24%5%
910
February1st to 15thNight
5%23%42%24%4
764
16th to endNight
7%21%39%27%3
684
March1st to 15thNight
316%38%32%7%1
780
16th to endNight
8%15%35%31%8%
733
April1st to 15thNight
11%14%34%32%7%
584
16th to endNight
19%11%28%29%9%1
579
May1st to 15thNight
18%8%22%34%14%1
585
16th to endNight
13%426%33%20%1
611
June1st to 15thNight
7%421%46%17%1
585
16th to endNight
4319%51%20%1
585
July1st to 15thNight
7%19%43%34%3
555
16th to endNight
48%42%41%2
612
August1st to 15thNight
6%111%45%32%3
575
16th to endNight
5%211%41%35%3
621
September1st to 15thNight
10%214%38%27%6%
585
16th to endNight
7%5%20%39%23%3
582
October1st to 15thNight
13%9%26%34%13%2
773
16th to endNight
9%12%30%33%11%2
866
November1st to 15thNight
6%12%32%36%9%2
950
16th to endNight
417%37%33%7%
975
December1st to 15thNight
5%24%39%24%5%
975
16th to endNight
6%20%38%28%5%
1040
Page generated at 2018-10-28 06:41:04. Version ac04

Copyright 2018 A. Danko


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