Prairie Grass Stargaze
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Prairie Grass Stargaze clear sky chart from 2005-11-05 to 2017-12-02.

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
35%
16422
17%
47509
9%
16375
43%
16375
26%
31186

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
24%
900
14%
2455
5%
895
32%
895
20%
1770
January16th to endNight
22%
960
13%
2496
4%
960
29%
960
17%
1899
February1st to 15thNight
24%
879
11%
2288
3%
875
30%
875
20%
1695
February16th to endNight
26%
753
15%
2015
5%
753
34%
753
22%
1418
March1st to 15thNight
29%
551
17%
1991
9%
551
40%
551
20%
1285
March16th to endNight
30%
576
12%
2112
10%
576
35%
576
15%
1478
April1st to 15thNight
30%
539
16%
1825
10%
539
40%
539
21%
1175
April16th to endNight
27%
540
18%
1620
11%
540
38%
540
20%
1148
May1st to 15thNight
33%
540
14%
1591
8%
540
39%
540
26%
1047
May16th to endNight
40%
563
15%
1498
6%
561
44%
561
28%
1003
June1st to 15thNight
50%
540
14%
1399
5%
540
54%
540
34%
897
June16th to endNight
57%
540
21%
1260
7%
540
60%
540
50%
749
July1st to 15thNight
62%
510
20%
1229
7%
510
65%
510
56%
687
July16th to endNight
67%
564
22%
1541
16%
531
68%
531
50%
792
August1st to 15thNight
64%
539
23%
1610
20%
536
68%
536
41%
887
August16th to endNight
59%
573
24%
1749
23%
573
66%
573
40%
954
September1st to 15thNight
55%
540
24%
1839
22%
540
64%
540
38%
960
September16th to endNight
43%
537
25%
1980
17%
537
57%
537
31%
1064
October1st to 15thNight
35%
714
24%
2154
13%
714
43%
714
31%
1289
October16th to endNight
33%
769
21%
2305
9%
769
41%
769
25%
1465
November1st to 15thNight
30%
950
21%
2587
8%
950
39%
950
27%
1698
November16th to endNight
28%
975
19%
2730
8%
975
37%
975
24%
1836
December1st to 15thNight
22%
910
10%
2547
3%
910
28%
910
16%
1892
December16th to endNight
21%
960
14%
2688
4%
960
30%
960
14%
2098

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
13%7%35%5%3445%7%38%
48935
Night
11%7%35%5%24446%42%
47682
Cloud CoverDay
13%7%36%5%3445%7%38%
48946
Night
11%7%36%5%24446%42%
47686
Cloud CoverDay
13%7%35%5%3445%7%39%
48944
Night
11%7%35%424446%43%
47686
TransparencyDay
44%6%14%22%10%1
48626
Night
41%6%13%23%13%1
47509
SeeingDay
16%8%30%27%14%3
6329
Night
14%9%34%29%10%
16423

By Month

Percentage Cloud Cover NE (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
7%11%7%9%8%346%7%6%27%
1482
16th to endDay
8%13%7%9%9%36%5%5%6%24%
1728
February1st to 15thDay
9%11%5%9%9%46%5%5%6%26%
1575
16th to endDay
11%9%48%8%36%5%6%6%30%
1470
March1st to 15thDay
16%9%6%8%5%24445%31%
1957
16th to endDay
16%11%6%7%5%245%5%7%29%
2112
April1st to 15thDay
17%7%36%5%3445%7%34%
2119
16th to endDay
25%10%35%42444430%
2340
May1st to 15thDay
21%7%245%34445%34%
2358
16th to endDay
16%5%25%5%345%5%8%36%
2617
June1st to 15thDay
16%5%25%5%35%45%7%39%
2556
16th to endDay
8%42443446%9%46%
2700
July1st to 15thDay
5%3134245%5%9%53%
2655
16th to endDay
5%313425%5%5%9%52%
2517
August1st to 15thDay
8%5%35%7%35%5%6%8%40%
2340
16th to endDay
11%41443446%8%48%
2453
September1st to 15thDay
11%423435%45%6%48%
2118
16th to endDay
13%423433347%49%
1974
October1st to 15thDay
15%6%34423345%46%
1800
16th to endDay
15%7%25%5%33345%43%
1917
November1st to 15thDay
11%8%36%42335%6%44%
1601
16th to endDay
11%10%28%6%3335%8%36%
1560
December1st to 15thDay
15%11%49%9%44445%25%
1450
16th to endDay
16%11%6%8%8%34246%24%
1536
January1st to 15thNight
8%7%5%8%7%46%6%5%7%31%
2455
16th to endNight
8%12%5%9%7%45%5%5%7%26%
2496
February1st to 15thNight
10%11%49%6%34446%33%
2285
16th to endNight
8%7%48%7%35%46%7%35%
2015
March1st to 15thNight
11%8%46%5%23447%40%
1979
16th to endNight
17%9%45%6%24446%33%
2112
April1st to 15thNight
15%7%25%424446%40%
1825
16th to endNight
20%9%35%424335%36%
1620
May1st to 15thNight
15%5%34424436%44%
1591
16th to endNight
12%425%5%25%47%8%40%
1496
June1st to 15thNight
10%5%23425%5%5%8%47%
1399
16th to endNight
5%2132145%6%8%59%
1260
July1st to 15thNight
211321345%7%63%
1302
16th to endNight
321232446%9%60%
1648
August1st to 15thNight
5%41341445%7%56%
1620
16th to endNight
8%323313336%59%
1749
September1st to 15thNight
9%313323347%57%
1839
16th to endNight
10%423223447%53%
1980
October1st to 15thNight
14%5%2431234451%
2154
16th to endNight
16%7%34412346%45%
2305
November1st to 15thNight
11%6%36%5%34345%45%
2587
16th to endNight
11%7%36%5%25%445%42%
2730
December1st to 15thNight
12%10%5%8%7%46%445%31%
2547
16th to endNight
16%12%5%8%6%35%5%45%26%
2688

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
7%11%7%9%8%445%7%6%27%
1482
16th to endDay
8%13%7%9%8%45%6%5%6%24%
1728
February1st to 15thDay
9%11%5%9%9%46%5%5%6%26%
1575
16th to endDay
11%9%47%8%36%6%6%6%29%
1470
March1st to 15thDay
16%10%6%8%5%2445%5%30%
1968
16th to endDay
15%11%6%7%5%2445%7%29%
2112
April1st to 15thDay
17%7%36%5%3435%7%34%
2119
16th to endDay
25%10%35%43434430%
2340
May1st to 15thDay
21%7%35%5%35%446%33%
2358
16th to endDay
15%5%35%5%35%5%6%8%36%
2617
June1st to 15thDay
16%5%245%3445%8%39%
2556
16th to endDay
8%4145%345%6%9%46%
2700
July1st to 15thDay
5%3134245%5%9%53%
2655
16th to endDay
5%213425%5%5%9%52%
2517
August1st to 15thDay
8%5%35%6%45%5%7%7%40%
2340
16th to endDay
11%42343445%7%48%
2453
September1st to 15thDay
10%423435%45%6%48%
2118
16th to endDay
13%5%13423347%49%
1974
October1st to 15thDay
15%6%24324335%46%
1800
16th to endDay
14%7%25%5%23345%43%
1917
November1st to 15thDay
11%8%36%42335%6%43%
1601
16th to endDay
11%9%27%6%2435%7%36%
1560
December1st to 15thDay
15%12%49%9%44446%25%
1450
16th to endDay
16%12%6%8%9%25%246%24%
1536
January1st to 15thNight
8%7%5%8%7%47%5%6%7%31%
2455
16th to endNight
8%12%6%9%7%36%5%5%7%26%
2496
February1st to 15thNight
10%12%49%6%345%46%33%
2278
16th to endNight
8%6%48%6%45%46%7%35%
2015
March1st to 15thNight
11%9%47%43335%6%40%
1991
16th to endNight
17%10%45%6%24446%33%
2112
April1st to 15thNight
15%7%25%4245%46%40%
1825
16th to endNight
20%10%35%424335%36%
1620
May1st to 15thNight
15%5%25%434345%44%
1590
16th to endNight
12%425%5%25%46%8%41%
1496
June1st to 15thNight
10%423325%5%6%8%47%
1399
16th to endNight
5%2132135%5%8%60%
1260
July1st to 15thNight
211321345%7%63%
1302
16th to endNight
321232446%9%60%
1648
August1st to 15thNight
5%31432345%8%56%
1620
16th to endNight
9%222313346%58%
1749
September1st to 15thNight
9%313323337%57%
1839
16th to endNight
10%42331345%7%53%
1980
October1st to 15thNight
14%6%24322335%51%
2154
16th to endNight
15%8%25%312346%45%
2305
November1st to 15thNight
11%6%36%5%33445%45%
2587
16th to endNight
11%8%36%5%34445%42%
2730
December1st to 15thNight
12%10%48%7%45%445%31%
2547
16th to endNight
16%12%5%8%6%35%445%26%
2688

Percentage Cloud Cover SE (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
7%11%7%9%8%445%6%6%27%
1482
16th to endDay
8%13%7%9%8%45%6%5%5%25%
1728
February1st to 15thDay
9%12%49%9%46%45%6%26%
1575
16th to endDay
11%9%47%7%36%5%7%6%29%
1470
March1st to 15thDay
16%10%6%8%5%2435%6%31%
1968
16th to endDay
16%12%5%7%5%2445%6%29%
2110
April1st to 15thDay
18%7%36%5%3435%7%35%
2119
16th to endDay
25%10%36%433345%30%
2340
May1st to 15thDay
22%6%345%2445%6%33%
2358
16th to endDay
15%6%25%5%345%5%8%36%
2617
June1st to 15thDay
16%5%2443445%8%39%
2556
16th to endDay
9%3144245%6%9%46%
2700
July1st to 15thDay
5%31342345%9%54%
2655
16th to endDay
5%3143245%6%9%53%
2517
August1st to 15thDay
8%5%35%6%36%6%6%7%41%
2340
16th to endDay
11%32443435%8%48%
2453
September1st to 15thDay
11%5%13425%446%49%
2118
16th to endDay
13%5%13414347%49%
1974
October1st to 15thDay
15%6%24334345%46%
1800
16th to endDay
15%6%25%423345%43%
1917
November1st to 15thDay
11%7%36%33235%7%43%
1601
16th to endDay
12%9%36%6%3435%7%37%
1560
December1st to 15thDay
15%11%5%8%10%44345%26%
1450
16th to endDay
16%13%6%8%7%34335%25%
1536
January1st to 15thNight
8%7%5%8%7%47%5%6%6%32%
2455
16th to endNight
9%11%5%10%6%45%6%5%7%27%
2496
February1st to 15thNight
10%12%5%8%6%35%446%33%
2278
16th to endNight
9%6%47%6%45%5%5%7%36%
2015
March1st to 15thNight
12%8%46%5%23446%40%
1991
16th to endNight
17%9%46%6%2445%5%34%
2112
April1st to 15thNight
16%7%25%41445%6%40%
1825
16th to endNight
21%9%34424335%36%
1620
May1st to 15thNight
16%5%24425%346%44%
1590
16th to endNight
13%5%25%425%5%6%8%41%
1496
June1st to 15thNight
10%5%134245%6%8%47%
1399
16th to endNight
5%2122135%5%7%60%
1260
July1st to 15thNight
311322335%8%63%
1302
16th to endNight
321222345%9%60%
1648
August1st to 15thNight
6%31432345%8%56%
1620
16th to endNight
9%313313246%59%
1749
September1st to 15thNight
9%313324337%57%
1839
16th to endNight
10%32332445%7%53%
1980
October1st to 15thNight
14%5%24312335%51%
2154
16th to endNight
15%8%34312346%45%
2305
November1st to 15thNight
11%7%26%5%23435%45%
2587
16th to endNight
11%8%36%435%436%43%
2730
December1st to 15thNight
13%10%48%8%35%445%31%
2547
16th to endNight
16%12%5%8%5%345%45%26%
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
53%7%14%16%8%
1483
16th to endDay
59%6%14%15%4
1728
February1st to 15thDay
56%5%15%15%5%
1576
16th to endDay
52%8%12%17%8%1
1470
March1st to 15thDay
53%5%14%19%5%
1968
16th to endDay
54%6%14%19%3
2112
April1st to 15thDay
47%5%15%20%8%1
2119
16th to endDay
57%5%12%17%7%
2340
May1st to 15thDay
51%6%12%20%9%
2358
16th to endDay
44%7%13%22%10%1
2621
June1st to 15thDay
42%7%15%23%9%
2556
16th to endDay
33%7%15%27%13%1
2700
July1st to 15thDay
26%7%16%31%13%3
2499
16th to endDay
26%7%17%28%17%2
2361
August1st to 15thDay
38%10%13%24%10%2
2326
16th to endDay
33%7%15%28%13%2
2453
September1st to 15thDay
34%6%14%26%17%
2118
16th to endDay
34%5%14%31%13%
1974
October1st to 15thDay
40%412%25%15%1
1800
16th to endDay
43%414%24%12%1
1917
November1st to 15thDay
40%5%13%21%17%1
1601
16th to endDay
46%5%19%18%9%1
1560
December1st to 15thDay
60%5%12%13%8%1
1450
16th to endDay
61%5%11%15%5%
1536
January1st to 15thNight
49%5%13%21%9%
2455
16th to endNight
53%7%15%16%6%
2496
February1st to 15thNight
51%6%12%20%8%
2288
16th to endNight
45%7%12%20%12%1
2015
March1st to 15thNight
44%5%14%24%9%1
1991
16th to endNight
51%6%13%20%6%
2112
April1st to 15thNight
43%6%12%24%12%
1825
16th to endNight
49%6%9%21%11%2
1620
May1st to 15thNight
41%5%14%21%14%2
1591
16th to endNight
38%8%14%22%13%2
1498
June1st to 15thNight
33%7%18%26%12%1
1399
16th to endNight
21%7%14%30%22%3
1260
July1st to 15thNight
18%5%17%33%19%5%
1229
16th to endNight
19%6%17%31%20%4
1541
August1st to 15thNight
26%6%14%32%18%2
1610
16th to endNight
26%5%14%30%17%4
1749
September1st to 15thNight
27%414%30%21%1
1839
16th to endNight
30%5%12%33%17%1
1980
October1st to 15thNight
35%311%26%19%3
2154
16th to endNight
40%414%23%15%1
2305
November1st to 15thNight
40%412%21%18%2
2587
16th to endNight
42%5%16%22%11%1
2730
December1st to 15thNight
53%6%13%17%8%
2547
16th to endNight
59%5%10%16%6%
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
15%12%36%25%7%2
90
16th to endDay
20%13%41%17%6%
96
February1st to 15thDay
16%20%41%18%3
90
16th to endDay
25%12%25%27%8%
81
March1st to 15thDay
15%21%34%27%1
90
16th to endDay
35%6%30%18%9%
96
April1st to 15thDay
20%11%36%21%9%
238
16th to endDay
30%13%28%18%7%2
450
May1st to 15thDay
22%13%29%25%7%1
468
16th to endDay
19%9%31%25%11%2
517
June1st to 15thDay
15%6%32%27%15%3
495
16th to endDay
8%6%36%32%13%2
495
July1st to 15thDay
7%427%33%21%5%
475
16th to endDay
7%325%35%22%4
515
August1st to 15thDay
8%423%34%25%3
493
16th to endDay
13%322%32%22%5%
493
September1st to 15thDay
12%329%32%17%4
273
16th to endDay
22%5%33%22%10%6%
135
October1st to 15thDay
17%11%42%17%9%2
135
16th to endDay
18%13%38%16%11%1
144
November1st to 15thDay
11%13%33%28%9%3
135
16th to endDay
27%14%37%17%3
135
December1st to 15thDay
22%14%34%21%6%1
94
16th to endDay
36%18%31%11%2
96
January1st to 15thNight
12%12%42%24%6%1
900
16th to endNight
15%14%39%26%4
960
February1st to 15thNight
17%12%38%24%7%
880
16th to endNight
11%13%41%22%9%1
753
March1st to 15thNight
14%9%38%27%9%
551
16th to endNight
22%8%31%27%8%1
576
April1st to 15thNight
20%9%38%25%6%
539
16th to endNight
24%9%34%21%8%1
540
May1st to 15thNight
18%9%35%27%9%
540
16th to endNight
15%7%31%33%11%
563
June1st to 15thNight
12%5%28%42%11%
540
16th to endNight
5%330%47%12%
540
July1st to 15thNight
4127%40%24%
510
16th to endNight
3125%46%22%1
564
August1st to 15thNight
6%122%42%24%2
539
16th to endNight
11%221%39%21%3
573
September1st to 15thNight
10%226%39%18%2
540
16th to endNight
11%6%34%30%14%2
537
October1st to 15thNight
16%10%34%26%10%
714
16th to endNight
19%10%31%29%8%
769
November1st to 15thNight
14%13%35%26%9%
950
16th to endNight
14%14%39%23%7%
975
December1st to 15thNight
18%11%39%24%5%
910
16th to endNight
24%10%33%24%6%
960
Page generated at 2017-12-03 10:16:49. Version ac04

Copyright 2017 A. Danko


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