Red Rock Canyon State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Red Rock Canyon State Park clear sky chart from 2005-11-05 to 2018-02-14.

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
71%
16260
40%
48710
31%
16219
79%
16219
65%
20439

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
68%
778
31%
2716
30%
776
76%
776
51%
1160
January16th to endNight
62%
832
39%
2612
32%
832
73%
832
51%
1221
February1st to 15thNight
66%
753
38%
2272
32%
752
76%
752
55%
1041
February16th to endNight
61%
632
37%
1895
32%
632
73%
632
52%
905
March1st to 15thNight
62%
720
34%
2160
28%
720
75%
720
58%
940
March16th to endNight
58%
768
39%
2010
24%
768
71%
768
65%
929
April1st to 15thNight
54%
719
37%
1799
15%
719
66%
719
61%
872
April16th to endNight
59%
720
41%
1800
17%
720
69%
720
71%
814
May1st to 15thNight
57%
582
40%
1662
24%
582
64%
582
75%
645
May16th to endNight
55%
561
38%
1685
23%
561
66%
561
71%
639
June1st to 15thNight
68%
408
39%
1488
34%
408
80%
408
82%
450
June16th to endNight
85%
360
42%
1440
48%
360
91%
360
87%
399
July1st to 15thNight
92%
340
37%
1360
45%
340
94%
340
68%
443
July16th to endNight
86%
530
39%
1558
34%
496
87%
496
68%
635
August1st to 15thNight
80%
717
38%
1790
24%
713
82%
713
85%
779
August16th to endNight
87%
764
47%
1910
30%
764
88%
764
86%
827
September1st to 15thNight
87%
720
44%
1830
31%
720
91%
720
80%
806
September16th to endNight
84%
716
51%
1980
42%
716
91%
716
87%
773
October1st to 15thNight
75%
720
41%
2001
34%
720
84%
720
68%
869
October16th to endNight
78%
768
48%
2355
45%
768
88%
768
72%
929
November1st to 15thNight
77%
760
39%
2470
38%
760
85%
760
68%
957
November16th to endNight
76%
780
42%
2535
43%
780
82%
780
64%
1020
December1st to 15thNight
70%
780
37%
2535
31%
780
80%
780
54%
1099
December16th to endNight
64%
832
36%
2847
33%
832
74%
832
46%
1287

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
211112235%77%
49356
Night
111112235%77%
48904
TransparencyDay
10%1416%28%37%
49041
Night
11%15%19%30%31%
48719
SeeingDay
5%11%26%29%19%7%
6329
Night
25%18%38%30%5%
16272

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%12212346%69%
1552
16th to endDay
6%211222346%65%
1960
February1st to 15thDay
212213347%69%
1883
16th to endDay
5%112223347%64%
1579
March1st to 15thDay
11111346%9%68%
1800
16th to endDay
21111245%9%69%
2211
April1st to 15thDay
211112236%74%
2149
16th to endDay
111236%80%
2160
May1st to 15thDay
11212384%
2286
16th to endDay
1111123480%
2429
June1st to 15thDay
111125%84%
2469
16th to endDay
11289%
2520
July1st to 15thDay
111111225%79%
2520
16th to endDay
211112235%76%
2498
August1st to 15thDay
11122385%
2160
16th to endDay
1113385%
2292
September1st to 15thDay
1123483%
2130
16th to endDay
1111289%
1980
October1st to 15thDay
2111122380%
1956
16th to endDay
211111235%79%
1867
November1st to 15thDay
11111335%78%
1719
16th to endDay
211112336%73%
1755
December1st to 15thDay
21121235%8%69%
1755
16th to endDay
321221335%7%66%
1726
January1st to 15thNight
321231235%7%67%
2716
16th to endNight
4213212245%68%
2612
February1st to 15thNight
1112313436%70%
2269
16th to endNight
5%111223336%68%
1895
March1st to 15thNight
11121235%7%71%
2160
16th to endNight
111212348%72%
2010
April1st to 15thNight
1111111236%75%
1799
16th to endNight
111135%83%
1800
May1st to 15thNight
1136%83%
1662
16th to endNight
1212485%
1684
June1st to 15thNight
12488%
1488
16th to endNight
1391%
1440
July1st to 15thNight
1111212482%
1440
16th to endNight
2111312479%
1666
August1st to 15thNight
112387%
1800
16th to endNight
2288%
1910
September1st to 15thNight
11112484%
1830
16th to endNight
111389%
1980
October1st to 15thNight
1121232381%
2001
16th to endNight
111112383%
2355
November1st to 15thNight
11111235%79%
2470
16th to endNight
21111337%75%
2535
December1st to 15thNight
311213238%70%
2535
16th to endNight
42221325%8%65%
2847

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
17%210%29%26%13%
1552
16th to endDay
21%27%25%26%16%
1960
February1st to 15thDay
15%27%22%31%20%
1883
16th to endDay
20%27%25%31%11%
1579
March1st to 15thDay
13%18%25%28%21%
1800
16th to endDay
11%210%26%29%19%
2211
April1st to 15thDay
13%16%23%35%20%
2149
16th to endDay
7%6%23%34%26%
2160
May1st to 15thDay
7%219%33%36%
2286
16th to endDay
8%1216%39%30%
2432
June1st to 15thDay
5%211%27%51%
2469
16th to endDay
5%1413%75%
2520
July1st to 15thDay
9%115%16%66%
2371
16th to endDay
12%1110%22%50%
2343
August1st to 15thDay
7%6%17%67%
2146
16th to endDay
5%1424%63%
2292
September1st to 15thDay
6%118%22%59%
2130
16th to endDay
5%17%33%52%
1980
October1st to 15thDay
10%1213%33%39%
1956
16th to endDay
10%1214%28%42%
1867
November1st to 15thDay
10%16%19%39%23%
1719
16th to endDay
13%16%22%31%24%
1755
December1st to 15thDay
14%311%22%29%18%
1755
16th to endDay
19%410%25%26%12%
1726
January1st to 15thNight
17%28%27%29%14%
2716
16th to endNight
19%17%23%27%19%
2612
February1st to 15thNight
17%17%20%29%22%
2280
16th to endNight
19%16%27%32%12%
1895
March1st to 15thNight
13%19%25%30%20%
2160
16th to endNight
10%19%32%29%15%
2010
April1st to 15thNight
12%16%29%33%15%
1799
16th to endNight
7%15%28%40%17%
1800
May1st to 15thNight
5%1323%39%27%
1663
16th to endNight
5%1421%43%24%
1685
June1st to 15thNight
3315%31%45%
1488
16th to endNight
216%18%70%
1440
July1st to 15thNight
8%17%15%65%
1360
16th to endNight
12%1310%25%48%
1558
August1st to 15thNight
5%27%22%61%
1790
16th to endNight
5%5%33%54%
1910
September1st to 15thNight
7%118%29%51%
1830
16th to endNight
38%37%48%
1980
October1st to 15thNight
10%1212%34%38%
2001
16th to endNight
8%1313%29%43%
2355
November1st to 15thNight
9%1420%38%25%
2470
16th to endNight
11%16%22%28%28%
2535
December1st to 15thNight
15%29%21%30%20%
2535
16th to endNight
18%410%25%26%14%
2847

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
11%10%18%35%18%5%
90
16th to endDay
9%11%19%30%20%7%
314
February1st to 15thDay
5%15%25%24%20%9%
320
16th to endDay
11%18%27%26%11%4
238
March1st to 15thDay
7%20%27%22%17%5%
270
16th to endDay
7%21%29%24%13%2
288
April1st to 15thDay
11%25%28%18%10%4
269
16th to endDay
8%24%32%24%7%3
270
May1st to 15thDay
315%39%21%15%3
288
16th to endDay
5%17%28%26%15%6%
330
June1st to 15thDay
5%12%35%23%17%5%
315
16th to endDay
19%33%26%19%9%
315
July1st to 15thDay
1228%34%20%11%
305
16th to endDay
3124%37%21%12%
327
August1st to 15thDay
35%30%33%17%9%
315
16th to endDay
324%37%21%14%
332
September1st to 15thDay
26%23%34%24%8%
315
16th to endDay
26%19%37%26%7%
315
October1st to 15thDay
412%26%33%20%2
315
16th to endDay
210%19%27%30%9%
283
November1st to 15thDay
45%11%28%35%14%
135
16th to endDay
28%20%32%29%6%
135
December1st to 15thDay
28%15%37%31%4
135
16th to endDay
9%10%15%30%28%7%
110
January1st to 15thNight
4316%40%27%6%
780
16th to endNight
6%420%37%26%4
832
February1st to 15thNight
2421%40%25%6%
760
16th to endNight
5%8%21%40%19%3
632
March1st to 15thNight
19%22%41%20%4
720
16th to endNight
29%26%36%21%3
768
April1st to 15thNight
311%27%35%19%2
719
16th to endNight
111%26%36%20%3
720
May1st to 15thNight
19%31%35%20%2
583
16th to endNight
112%28%32%24%
563
June1st to 15thNight
5%24%43%25%
408
16th to endNight
13%56%27%2
360
July1st to 15thNight
1140%53%1
340
16th to endNight
17%36%48%3
530
August1st to 15thNight
14%36%43%3
717
16th to endNight
9%34%45%9%
764
September1st to 15thNight
8%38%43%8%
720
16th to endNight
112%34%42%9%
716
October1st to 15thNight
1415%40%32%6%
720
16th to endNight
1313%31%38%11%
768
November1st to 15thNight
1314%39%33%7%
760
16th to endNight
2314%38%33%7%
780
December1st to 15thNight
5%415%41%27%4
780
16th to endNight
5%5%18%40%23%4
832
Page generated at 2018-02-15 07:58:49. Version ac04

Copyright 2018 A. Danko


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