Dead Horse Point State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Dead Horse Point State Park clear sky chart from 2005-11-05 to 2018-01-12.

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
70%
16258
29%
48490
26%
16221
73%
16221
43%
26000

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
74%
760
24%
2471
26%
760
76%
760
39%
1323
January16th to endNight
67%
768
27%
2496
29%
768
70%
768
32%
1460
February1st to 15thNight
68%
698
20%
2288
23%
698
70%
698
34%
1308
February16th to endNight
60%
632
30%
1917
25%
632
67%
632
35%
1099
March1st to 15thNight
65%
720
32%
1980
27%
720
69%
720
46%
1090
March16th to endNight
63%
768
28%
2112
20%
768
68%
768
40%
1219
April1st to 15thNight
53%
596
26%
1855
20%
596
61%
596
35%
1045
April16th to endNight
56%
540
31%
1719
23%
540
66%
540
39%
890
May1st to 15thNight
63%
540
27%
1619
23%
539
67%
539
40%
879
May16th to endNight
61%
561
27%
1685
21%
561
66%
561
43%
871
June1st to 15thNight
72%
540
31%
1443
24%
540
75%
540
58%
715
June16th to endNight
78%
540
34%
1493
32%
540
80%
540
63%
697
July1st to 15thNight
76%
510
19%
1530
18%
510
77%
510
42%
833
July16th to endNight
81%
564
24%
1593
22%
531
81%
531
40%
892
August1st to 15thNight
78%
539
26%
1611
24%
536
78%
536
43%
862
August16th to endNight
80%
573
34%
1821
35%
573
81%
573
45%
926
September1st to 15thNight
76%
594
32%
1854
32%
594
79%
594
46%
921
September16th to endNight
77%
716
39%
1980
30%
716
82%
716
58%
967
October1st to 15thNight
73%
720
34%
2154
27%
720
78%
720
54%
1019
October16th to endNight
75%
768
41%
2304
34%
768
79%
768
54%
1107
November1st to 15thNight
75%
760
34%
2332
31%
760
78%
760
47%
1157
November16th to endNight
72%
917
34%
2672
31%
917
74%
917
48%
1361
December1st to 15thNight
69%
975
24%
2730
21%
975
71%
975
42%
1528
December16th to endNight
60%
959
17%
2831
16%
959
62%
959
27%
1831

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
331442446%7%55%
48832
Night
441442445%7%55%
48685
TransparencyDay
25%38%22%23%16%
48527
Night
26%38%23%23%14%
48491
SeeingDay
7%9%17%32%25%7%
5856
Night
6%311%41%31%5%
16270

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
5%7%35%6%5%7%7%9%13%28%
1710
16th to endDay
6%4146%37%7%9%11%37%
1728
February1st to 15thDay
5%426%9%46%6%9%13%32%
1575
16th to endDay
7%6%245%345%6%8%44%
1554
March1st to 15thDay
25%2442446%8%53%
1980
16th to endDay
4425%33435%9%53%
2112
April1st to 15thDay
4423434446%57%
2093
16th to endDay
3313434346%60%
2238
May1st to 15thDay
342442445%7%55%
2331
16th to endDay
331332445%7%58%
2429
June1st to 15thDay
2213213235%70%
2511
16th to endDay
111121223478%
2463
July1st to 15thDay
22134246%7%8%55%
2340
16th to endDay
23235%36%6%8%9%47%
2467
August1st to 15thDay
33145%35%6%7%7%50%
2340
16th to endDay
22134245%5%8%59%
2381
September1st to 15thDay
42133245%5%7%59%
2103
16th to endDay
2312212236%72%
1980
October1st to 15thDay
4212223346%66%
1806
16th to endDay
2212312246%68%
1920
November1st to 15thDay
5%312312346%66%
1854
16th to endDay
434322337%62%
1602
December1st to 15thDay
5%6%145%25%5%8%8%45%
1560
16th to endDay
6%7%37%7%48%7%7%9%29%
1755
January1st to 15thNight
45%24335%46%9%51%
2471
16th to endNight
7%5%245%36%5%48%45%
2496
February1st to 15thNight
35%25%5%45%5%5%10%46%
2277
16th to endNight
5%6%35%5%3445%7%48%
1917
March1st to 15thNight
442331445%7%56%
1980
16th to endNight
4424435%5%5%7%51%
2112
April1st to 15thNight
45%245%35%45%6%52%
1855
16th to endNight
5%32342445%7%56%
1719
May1st to 15thNight
4415%435%446%55%
1619
16th to endNight
331342445%7%57%
1684
June1st to 15thNight
3112324447%64%
1443
16th to endNight
122312346%71%
1493
July1st to 15thNight
12245%35%6%7%10%48%
1620
16th to endNight
12145%48%7%7%9%46%
1701
August1st to 15thNight
3314425%5%7%10%50%
1620
16th to endNight
22144236%6%8%56%
1821
September1st to 15thNight
431332445%7%59%
1854
16th to endNight
422322225%71%
1980
October1st to 15thNight
5%12313346%67%
2154
16th to endNight
4312212345%67%
2304
November1st to 15thNight
3323324346%63%
2332
16th to endNight
5%323223346%62%
2672
December1st to 15thNight
6%5%1432345%7%54%
2730
16th to endNight
7%8%36%5%46%5%5%9%36%
2831

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
39%5%18%32%4
1711
16th to endDay
33%417%32%10%1
1728
February1st to 15thDay
37%420%23%12%1
1575
16th to endDay
35%27%32%20%2
1554
March1st to 15thDay
27%27%34%22%5%
1980
16th to endDay
27%26%29%27%6%
2112
April1st to 15thDay
27%3424%26%13%
2093
16th to endDay
25%2422%32%13%
2238
May1st to 15thDay
26%3418%32%14%
2331
16th to endDay
22%35%17%30%19%
2432
June1st to 15thDay
16%2110%27%41%
2511
16th to endDay
11%15%20%60%
2463
July1st to 15thDay
24%5%6%13%17%32%
2201
16th to endDay
25%6%8%20%17%21%
2312
August1st to 15thDay
27%5%7%18%16%24%
2325
16th to endDay
21%4417%26%24%
2381
September1st to 15thDay
22%46%15%23%28%
2103
16th to endDay
15%2319%36%23%
1980
October1st to 15thDay
19%35%24%33%12%
1806
16th to endDay
17%26%29%37%6%
1920
November1st to 15thDay
19%28%35%28%5%
1854
16th to endDay
22%111%40%21%1
1602
December1st to 15thDay
32%5%19%32%9%
1560
16th to endDay
44%6%21%21%5%
1755
January1st to 15thNight
28%420%34%12%
2471
16th to endNight
35%413%31%14%1
2496
February1st to 15thNight
32%415%29%13%3
2288
16th to endNight
33%36%31%21%3
1917
March1st to 15thNight
25%26%30%27%6%
1980
16th to endNight
29%35%24%29%6%
2112
April1st to 15thNight
31%3420%25%15%
1855
16th to endNight
26%3418%33%14%
1719
May1st to 15thNight
27%36%14%30%16%
1620
16th to endNight
24%35%15%31%18%
1685
June1st to 15thNight
16%3210%28%39%
1443
16th to endNight
14%16%16%59%
1493
July1st to 15thNight
27%37%15%14%31%
1530
16th to endNight
27%5%9%18%19%19%
1593
August1st to 15thNight
23%6%9%18%20%21%
1611
16th to endNight
21%6%6%14%22%28%
1821
September1st to 15thNight
23%36%15%16%35%
1854
16th to endNight
17%2415%29%29%
1980
October1st to 15thNight
18%25%22%32%19%
2154
16th to endNight
19%2420%39%13%
2304
November1st to 15thNight
23%25%25%33%9%
2332
16th to endNight
22%26%30%30%6%
2672
December1st to 15thNight
28%313%34%18%1
2730
16th to endNight
42%421%26%5%
2831

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
29%48%25%22%8%
123
16th to endDay
9%4442%31%8%
96
February1st to 15thDay
14%3435%28%13%
90
16th to endDay
12%16%16%32%16%6%
165
March1st to 15thDay
7%9%21%36%22%2
270
16th to endDay
9%18%24%27%16%3
288
April1st to 15thDay
10%20%25%22%15%5%
269
16th to endDay
12%20%26%25%13%1
270
May1st to 15thDay
8%15%30%27%14%3
288
16th to endDay
7%14%22%26%22%5%
330
June1st to 15thDay
6%9%18%29%29%6%
486
16th to endDay
36%16%32%32%8%
438
July1st to 15thDay
4216%32%35%8%
305
16th to endDay
2312%37%36%7%
327
August1st to 15thDay
5%314%40%26%9%
315
16th to endDay
6%111%33%36%10%
332
September1st to 15thDay
25%20%33%26%11%
315
16th to endDay
5%11%17%24%28%12%
315
October1st to 15thDay
411%16%30%23%14%
141
16th to endDay
9%5%10%34%29%9%
144
November1st to 15thDay
27%17%34%31%7%
135
16th to endDay
10%414%48%19%3
135
December1st to 15thDay
8%214%48%18%5%
135
16th to endDay
12%47%46%23%4
144
January1st to 15thNight
7%46%46%30%5%
764
16th to endNight
9%28%44%26%7%
768
February1st to 15thNight
7%211%49%24%5%
704
16th to endNight
8%415%50%17%3
632
March1st to 15thNight
5%6%14%45%26%1
720
16th to endNight
6%7%15%44%24%1
768
April1st to 15thNight
7%9%21%40%17%2
596
16th to endNight
7%10%22%35%21%2
540
May1st to 15thNight
47%17%43%23%3
540
16th to endNight
47%19%34%29%3
563
June1st to 15thNight
3416%40%32%3
540
16th to endNight
2210%40%40%4
540
July1st to 15thNight
216%31%51%6%
510
16th to endNight
2426%57%7%
564
August1st to 15thNight
6%433%48%6%
539
16th to endNight
316%31%47%10%
573
September1st to 15thNight
6%17%34%41%8%
594
16th to endNight
5%110%30%42%9%
716
October1st to 15thNight
5%412%43%29%4
720
16th to endNight
7%19%37%36%7%
768
November1st to 15thNight
5%29%45%33%4
760
16th to endNight
7%310%43%29%5%
917
December1st to 15thNight
9%29%51%24%2
975
16th to endNight
11%49%44%25%3
959
Page generated at 2018-01-12 20:01:34. Version ac04

Copyright 2018 A. Danko


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