Badlands Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Badlands Observatory clear sky chart from 2005-11-05 to

2017-09-12
.

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
46%
16094
21%
46778
13%
16051
52%
16051
32%
28405

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
40%
900
18%
2506
12%
895
45%
895
28%
1629
January16th to endNight
35%
960
20%
2688
10%
960
43%
960
29%
1707
February1st to 15thNight
35%
759
16%
2269
9%
759
41%
759
25%
1484
February16th to endNight
38%
632
19%
1894
11%
632
45%
632
29%
1186
March1st to 15thNight
42%
720
19%
2160
11%
720
49%
720
30%
1335
March16th to endNight
41%
594
17%
2025
13%
594
48%
594
23%
1276
April1st to 15thNight
39%
539
16%
1798
13%
539
47%
539
24%
1120
April16th to endNight
39%
540
15%
1674
12%
540
45%
540
22%
1128
May1st to 15thNight
46%
540
17%
1578
11%
540
52%
540
30%
995
May16th to endNight
41%
563
15%
1498
8%
561
44%
561
28%
1010
June1st to 15thNight
45%
540
13%
1440
6%
540
48%
540
31%
943
June16th to endNight
52%
540
17%
1440
8%
540
56%
540
46%
817
July1st to 15thNight
62%
510
17%
1360
9%
510
65%
510
47%
761
July16th to endNight
67%
564
24%
1416
15%
531
70%
531
53%
749
August1st to 15thNight
58%
539
22%
1516
17%
536
63%
536
42%
860
August16th to endNight
64%
573
29%
1872
27%
573
72%
573
46%
909
September1st to 15thNight
58%
530
25%
1788
21%
530
68%
530
41%
899
September16th to endNight
57%
492
30%
1815
29%
492
66%
492
41%
853
October1st to 15thNight
42%
558
27%
1878
19%
558
52%
558
27%
1126
October16th to endNight
47%
866
22%
2274
11%
866
52%
866
35%
1403
November1st to 15thNight
46%
875
27%
2275
13%
875
53%
875
38%
1370
November16th to endNight
46%
900
26%
2406
14%
900
53%
900
35%
1462
December1st to 15thNight
38%
900
16%
2520
8%
900
45%
900
27%
1655
December16th to endNight
42%
960
20%
2688
11%
960
51%
960
29%
1728

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
8%5%2442445%8%49%
47897
Night
7%5%25%42445%7%49%
46945
Cloud CoverDay
8%5%2442445%8%49%
47907
Night
7%5%2442445%7%48%
46948
Cloud CoverDay
8%5%2442445%8%49%
47907
Night
7%5%25%42445%7%48%
46950
Cloud CoverDay
8%5%2442445%7%49%
47905
Night
7%5%2442445%7%49%
46950
TransparencyDay
32%6%15%26%15%3
47581
Night
32%7%15%25%15%3
46778
SeeingDay
10%6%27%33%18%3
6056
Night
9%6%31%38%12%
16098

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
46%47%7%345%37%44%
1432
16th to endDay
38%26%5%2445%9%46%
1536
February1st to 15thDay
8%10%46%5%445%46%40%
1603
16th to endDay
46%36%5%35%5%5%8%45%
1580
March1st to 15thDay
5%5%25%4245%5%8%49%
1790
16th to endDay
10%7%35%5%35%5%5%7%40%
2197
April1st to 15thDay
11%7%2442346%8%44%
2150
16th to endDay
15%6%15%5%345%5%8%36%
2286
May1st to 15thDay
12%5%25%42445%7%45%
2371
16th to endDay
15%6%25%425%5%6%8%38%
2616
June1st to 15thDay
11%41442446%9%47%
2520
16th to endDay
421231345%9%61%
2520
July1st to 15thDay
5%21333346%8%57%
2520
16th to endDay
42123235%6%8%60%
2656
August1st to 15thDay
5%314435%5%7%9%50%
2436
16th to endDay
6%31331335%6%61%
2327
September1st to 15thDay
8%313323347%58%
2091
16th to endDay
8%312112246%64%
1815
October1st to 15thDay
12%5%25%323236%51%
1752
16th to endDay
8%5%24424446%51%
1586
November1st to 15thDay
6%33433436%6%53%
1583
16th to endDay
7%6%34425%5%5%8%46%
1554
December1st to 15thDay
5%7%46%6%245%5%7%43%
1440
16th to endDay
6%7%46%5%3436%8%44%
1536
January1st to 15thNight
4437%7%35%5%5%7%44%
2506
16th to endNight
39%45%4245%6%7%45%
2688
February1st to 15thNight
7%8%27%5%35%46%7%41%
2266
16th to endNight
6%7%36%5%3445%7%45%
1894
March1st to 15thNight
7%6%35%5%2445%8%45%
2147
16th to endNight
11%6%35%43446%8%40%
2025
April1st to 15thNight
12%5%244345%5%7%43%
1798
16th to endNight
16%6%25%5%24447%39%
1674
May1st to 15thNight
10%5%2343346%7%47%
1578
16th to endNight
14%425%43445%8%42%
1497
June1st to 15thNight
12%42433345%9%45%
1440
16th to endNight
5%21242445%8%57%
1440
July1st to 15thNight
42133145%6%8%58%
1440
16th to endNight
2223235%6%9%60%
1512
August1st to 15thNight
33144235%6%8%55%
1524
16th to endNight
421321335%7%63%
1872
September1st to 15thNight
7%21232345%6%60%
1788
16th to endNight
7%212312346%63%
1815
October1st to 15thNight
12%5%25%323446%48%
1878
16th to endNight
9%5%244345%5%7%49%
2274
November1st to 15thNight
6%5%24325%45%7%51%
2275
16th to endNight
5%5%244335%5%8%51%
2406
December1st to 15thNight
6%6%36%5%345%5%7%42%
2520
16th to endNight
5%7%35%5%35%45%8%45%
2688

Percentage Cloud Cover NW (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
46%39%7%345%48%43%
1433
16th to endDay
48%37%4245%5%8%46%
1536
February1st to 15thDay
8%9%5%5%5%25%5%5%5%40%
1603
16th to endDay
46%36%5%36%45%8%45%
1580
March1st to 15thDay
5%5%25%4345%5%8%48%
1800
16th to endDay
10%7%35%5%345%6%7%40%
2196
April1st to 15thDay
11%6%3442445%9%44%
2150
16th to endDay
16%6%25%5%3445%8%36%
2286
May1st to 15thDay
12%5%25%42445%7%45%
2371
16th to endDay
15%6%25%42446%9%38%
2616
June1st to 15thDay
11%42442446%9%47%
2520
16th to endDay
321232345%9%61%
2520
July1st to 15thDay
5%21342436%9%56%
2520
16th to endDay
42122235%5%8%59%
2656
August1st to 15thDay
42244245%7%10%50%
2436
16th to endDay
6%312323346%61%
2327
September1st to 15thDay
8%313323347%58%
2091
16th to endDay
8%212212347%64%
1815
October1st to 15thDay
12%5%24323347%50%
1752
16th to endDay
8%5%14425%35%7%50%
1586
November1st to 15thDay
5%43443346%7%52%
1583
16th to endDay
7%6%25%335%46%8%46%
1554
December1st to 15thDay
5%7%47%6%2445%7%44%
1440
16th to endDay
7%7%46%5%2445%7%45%
1536
January1st to 15thNight
45%47%6%35%5%5%7%44%
2506
16th to endNight
38%45%5%345%6%7%45%
2688
February1st to 15thNight
7%8%36%5%4446%7%41%
2259
16th to endNight
6%7%36%5%3446%6%45%
1894
March1st to 15thNight
7%6%36%5%2346%7%45%
2160
16th to endNight
11%6%35%5%3446%8%40%
2022
April1st to 15thNight
12%5%345%3445%7%42%
1798
16th to endNight
15%7%25%6%24446%39%
1674
May1st to 15thNight
10%6%1342446%7%47%
1577
16th to endNight
14%425%43446%7%42%
1498
June1st to 15thNight
12%42442445%9%45%
1440
16th to endNight
5%2124245%6%8%56%
1440
July1st to 15thNight
42123145%7%8%57%
1440
16th to endNight
21332447%8%60%
1512
August1st to 15thNight
332442447%8%54%
1524
16th to endNight
431231345%7%63%
1872
September1st to 15thNight
7%21232345%6%60%
1788
16th to endNight
7%212213345%64%
1815
October1st to 15thNight
12%5%24423445%48%
1878
16th to endNight
9%4244245%5%7%48%
2274
November1st to 15thNight
6%6%24324447%52%
2275
16th to endNight
5%5%35%425%45%8%50%
2406
December1st to 15thNight
6%6%46%5%345%5%7%42%
2520
16th to endNight
47%35%5%35%5%48%45%
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
36%37%8%345%37%44%
1432
16th to endDay
48%27%42445%8%46%
1536
February1st to 15thDay
8%10%5%6%5%345%46%39%
1603
16th to endDay
46%36%5%35%5%5%8%46%
1580
March1st to 15thDay
5%5%25%4245%5%8%49%
1800
16th to endDay
10%6%35%5%345%5%8%40%
2197
April1st to 15thDay
11%7%2442346%8%44%
2150
16th to endDay
15%6%25%6%3446%8%36%
2286
May1st to 15thDay
12%5%25%42445%7%45%
2371
16th to endDay
15%5%25%3245%6%8%38%
2616
June1st to 15thDay
11%41441446%9%47%
2520
16th to endDay
321232345%9%61%
2520
July1st to 15thDay
5%21332436%8%57%
2520
16th to endDay
321232345%8%59%
2656
August1st to 15thDay
5%3144345%8%9%50%
2436
16th to endDay
6%31332335%6%61%
2327
September1st to 15thDay
8%313323237%58%
2091
16th to endDay
8%212213247%63%
1815
October1st to 15thDay
12%5%25%323336%51%
1752
16th to endDay
8%5%2442445%6%51%
1586
November1st to 15thDay
5%32433436%7%53%
1583
16th to endDay
7%6%34425%5%6%8%46%
1554
December1st to 15thDay
5%7%47%5%245%5%7%44%
1440
16th to endDay
7%7%36%5%3335%8%44%
1536
January1st to 15thNight
4437%7%36%5%5%7%44%
2506
16th to endNight
39%45%4345%6%7%45%
2688
February1st to 15thNight
7%8%37%5%345%6%7%41%
2259
16th to endNight
6%7%36%43446%7%45%
1894
March1st to 15thNight
7%6%35%5%2446%8%45%
2160
16th to endNight
11%6%35%5%245%6%8%40%
2025
April1st to 15thNight
12%5%244345%5%8%42%
1798
16th to endNight
16%7%25%5%24447%39%
1674
May1st to 15thNight
10%5%2442446%7%46%
1577
16th to endNight
14%42443445%8%42%
1497
June1st to 15thNight
12%32443345%9%45%
1440
16th to endNight
5%2123245%6%8%57%
1440
July1st to 15thNight
42133235%6%8%58%
1440
16th to endNight
2123245%6%8%60%
1512
August1st to 15thNight
33244135%6%8%55%
1524
16th to endNight
421321335%7%63%
1872
September1st to 15thNight
6%21222345%6%60%
1788
16th to endNight
7%213312346%63%
1815
October1st to 15thNight
13%5%24424446%48%
1878
16th to endNight
8%5%244245%5%7%49%
2274
November1st to 15thNight
6%5%2432445%8%51%
2275
16th to endNight
5%5%25%4245%48%50%
2406
December1st to 15thNight
6%6%37%5%35%46%7%42%
2520
16th to endNight
47%35%5%35%45%8%45%
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
5%6%47%6%445%47%43%
1432
16th to endDay
48%27%4235%5%7%47%
1536
February1st to 15thDay
8%9%5%5%6%3445%5%40%
1603
16th to endDay
45%36%6%345%5%9%45%
1580
March1st to 15thDay
5%5%25%4345%6%8%49%
1800
16th to endDay
10%7%35%5%345%6%7%40%
2195
April1st to 15thDay
11%7%2432346%8%44%
2150
16th to endDay
15%6%25%5%25%46%8%36%
2286
May1st to 15thDay
12%5%2443445%7%45%
2371
16th to endDay
15%6%24325%5%6%8%38%
2616
June1st to 15thDay
11%42342446%8%47%
2520
16th to endDay
421322445%8%61%
2520
July1st to 15thDay
5%21342345%8%58%
2520
16th to endDay
42123135%6%8%60%
2656
August1st to 15thDay
5%323335%5%7%9%51%
2436
16th to endDay
7%313313346%61%
2327
September1st to 15thDay
8%313323336%59%
2091
16th to endDay
8%311213246%63%
1815
October1st to 15thDay
11%5%25%423236%52%
1752
16th to endDay
8%5%2433445%6%51%
1586
November1st to 15thDay
6%42443345%7%53%
1583
16th to endDay
6%6%35%3345%5%8%46%
1554
December1st to 15thDay
6%6%47%6%245%5%7%43%
1440
16th to endDay
7%6%37%5%2445%7%45%
1536
January1st to 15thNight
45%36%7%35%5%6%7%44%
2506
16th to endNight
38%35%425%6%5%7%46%
2688
February1st to 15thNight
8%7%37%5%35%46%6%41%
2259
16th to endNight
6%7%35%435%45%7%45%
1894
March1st to 15thNight
7%6%35%43446%9%44%
2160
16th to endNight
11%6%35%425%45%9%40%
2025
April1st to 15thNight
12%5%245%2445%7%43%
1798
16th to endNight
16%6%345%25%447%39%
1674
May1st to 15thNight
11%5%225%2445%8%47%
1577
16th to endNight
13%425%43445%8%42%
1497
June1st to 15thNight
13%32432445%9%46%
1440
16th to endNight
5%21232445%10%56%
1440
July1st to 15thNight
421331446%8%59%
1440
16th to endNight
21123235%6%9%60%
1512
August1st to 15thNight
4225%4235%6%8%55%
1524
16th to endNight
421322335%6%64%
1872
September1st to 15thNight
7%21331345%6%60%
1788
16th to endNight
7%213213346%63%
1815
October1st to 15thNight
12%5%25%324346%49%
1878
16th to endNight
9%5%2443445%6%48%
2274
November1st to 15thNight
6%5%2432446%6%52%
2275
16th to endNight
5%5%244245%5%8%50%
2406
December1st to 15thNight
6%6%36%6%345%6%6%42%
2520
16th to endNight
5%7%26%6%35%448%46%
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
38%6%16%27%8%1
1433
16th to endDay
34%7%23%21%10%1
1536
February1st to 15thDay
43%7%16%21%8%1
1604
16th to endDay
34%8%19%24%10%3
1580
March1st to 15thDay
31%7%18%29%12%1
1800
16th to endDay
40%9%15%25%9%
2197
April1st to 15thDay
36%6%16%30%8%1
2150
16th to endDay
43%8%14%23%9%
2286
May1st to 15thDay
37%6%15%28%11%
2371
16th to endDay
40%9%19%21%8%
2620
June1st to 15thDay
33%8%17%25%13%1
2520
16th to endDay
18%6%15%31%20%6%
2520
July1st to 15thDay
24%6%13%23%24%7%
2371
16th to endDay
19%5%11%28%24%10%
2489
August1st to 15thDay
26%7%17%24%17%6%
2420
16th to endDay
23%411%27%23%9%
2327
September1st to 15thDay
26%410%27%23%7%
2091
16th to endDay
21%310%34%25%3
1815
October1st to 15thDay
35%414%21%20%4
1752
16th to endDay
32%5%16%27%14%2
1586
November1st to 15thDay
29%5%15%25%19%5%
1583
16th to endDay
32%7%16%25%14%1
1554
December1st to 15thDay
38%7%18%22%11%1
1440
16th to endDay
38%6%17%23%12%1
1536
January1st to 15thNight
37%7%17%24%11%2
2506
16th to endNight
35%7%18%24%12%1
2688
February1st to 15thNight
40%7%17%23%9%1
2269
16th to endNight
37%6%16%25%10%3
1894
March1st to 15thNight
35%6%16%25%14%2
2160
16th to endNight
40%7%17%23%11%1
2025
April1st to 15thNight
38%7%14%24%12%2
1798
16th to endNight
44%7%13%22%11%
1674
May1st to 15thNight
34%8%15%27%12%1
1578
16th to endNight
39%8%17%22%11%
1498
June1st to 15thNight
35%8%15%25%13%1
1440
16th to endNight
22%7%17%28%17%5%
1440
July1st to 15thNight
21%7%14%26%23%7%
1360
16th to endNight
17%6%14%28%20%12%
1416
August1st to 15thNight
24%8%13%26%20%7%
1516
16th to endNight
19%6%10%28%26%9%
1872
September1st to 15thNight
23%5%11%25%25%8%
1788
16th to endNight
21%5%9%34%24%5%
1815
October1st to 15thNight
36%5%10%23%18%5%
1878
16th to endNight
32%5%15%23%17%4
2274
November1st to 15thNight
29%5%13%23%21%6%
2275
16th to endNight
31%6%16%26%15%3
2406
December1st to 15thNight
38%7%15%25%9%2
2520
16th to endNight
36%7%18%22%13%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
6%5%24%36%18%7%
90
16th to endDay
12%7%23%34%15%6%
96
February1st to 15thDay
10%10%41%32%6%
90
16th to endDay
7%19%38%17%9%7%
81
March1st to 15thDay
5%6%45%26%10%5%
90
16th to endDay
18%11%31%20%15%4
199
April1st to 15thDay
11%13%41%27%5%
269
16th to endDay
21%9%26%27%13%1
396
May1st to 15thDay
14%9%30%25%17%3
468
16th to endDay
18%6%28%30%12%3
517
June1st to 15thDay
10%6%24%34%18%5%
495
16th to endDay
5%5%28%38%19%2
495
July1st to 15thDay
6%320%43%23%3
475
16th to endDay
4221%44%25%1
515
August1st to 15thDay
4223%44%22%2
493
16th to endDay
8%322%29%26%9%
367
September1st to 15thDay
8%7%22%28%24%8%
278
16th to endDay
13%5%25%32%18%4
90
October1st to 15thDay
16%328%27%11%12%
90
16th to endDay
14%423%25%23%8%
96
November1st to 15thDay
4326%31%26%7%
90
16th to endDay
25%6%30%22%15%
90
December1st to 15thDay
12%10%38%23%12%3
90
16th to endDay
8%7%43%26%13%1
96
January1st to 15thNight
6%10%33%36%11%
900
16th to endNight
9%10%37%34%8%
960
February1st to 15thNight
11%7%37%34%7%
763
16th to endNight
9%7%38%32%10%1
632
March1st to 15thNight
9%6%32%40%9%1
720
16th to endNight
13%7%31%37%10%
594
April1st to 15thNight
14%7%35%38%5%
539
16th to endNight
19%8%26%33%11%
540
May1st to 15thNight
12%7%30%36%11%1
540
16th to endNight
16%6%31%33%11%
563
June1st to 15thNight
12%432%37%11%
540
16th to endNight
5%435%44%11%
540
July1st to 15thNight
3128%45%19%1
510
16th to endNight
2125%55%14%
564
August1st to 15thNight
5%28%49%14%
539
16th to endNight
5%125%47%19%
573
September1st to 15thNight
9%227%40%19%1
530
16th to endNight
8%426%38%20%1
492
October1st to 15thNight
16%7%29%31%14%
558
16th to endNight
11%7%28%37%14%
866
November1st to 15thNight
9%7%32%38%11%
875
16th to endNight
8%8%32%38%11%
900
December1st to 15thNight
9%8%34%36%10%
900
16th to endNight
9%7%32%38%11%
960
Page generated at 2017-09-13 05:39:03. Version ac04

Copyright 2017 A. Danko


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