Crossroads OHV Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Crossroads OHV Area clear sky chart from 2005-11-05 to 2017-09-24.

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
79%
15902
39%
47022
34%
15863
83%
15863
62%
21027

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
75%
719
35%
2327
34%
716
81%
716
51%
1065
January16th to endNight
71%
768
39%
2466
38%
768
78%
768
49%
1175
February1st to 15thNight
76%
697
39%
2111
36%
697
84%
697
56%
975
February16th to endNight
68%
632
35%
1895
36%
632
73%
632
49%
948
March1st to 15thNight
70%
720
38%
2063
34%
720
79%
720
61%
946
March16th to endNight
74%
768
38%
2112
31%
768
79%
768
59%
1014
April1st to 15thNight
66%
719
35%
1895
20%
719
74%
719
63%
900
April16th to endNight
72%
616
46%
1696
29%
616
82%
616
80%
696
May1st to 15thNight
76%
539
41%
1619
30%
539
81%
539
73%
633
May16th to endNight
76%
561
40%
1685
30%
561
81%
561
75%
663
June1st to 15thNight
83%
540
36%
1620
31%
540
85%
540
77%
627
June16th to endNight
90%
540
36%
1620
33%
540
90%
540
81%
614
July1st to 15thNight
88%
510
29%
1530
25%
510
88%
510
61%
688
July16th to endNight
84%
564
31%
1593
26%
531
85%
531
49%
798
August1st to 15thNight
89%
561
37%
1633
28%
558
90%
558
63%
729
August16th to endNight
88%
764
40%
1910
29%
764
89%
764
62%
994
September1st to 15thNight
87%
720
35%
1965
30%
720
88%
720
63%
925
September16th to endNight
86%
692
48%
1914
40%
692
91%
692
78%
802
October1st to 15thNight
80%
660
44%
1815
36%
660
85%
660
69%
816
October16th to endNight
84%
704
45%
2112
42%
704
89%
704
70%
870
November1st to 15thNight
84%
700
40%
2265
41%
700
89%
700
65%
919
November16th to endNight
79%
720
42%
2340
43%
720
84%
720
63%
961
December1st to 15thNight
77%
720
38%
2340
38%
720
82%
720
52%
1067
December16th to endNight
70%
768
38%
2496
37%
768
76%
768
46%
1202

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
212212235%73%
47904
Night
212212335%73%
47218
TransparencyDay
13%2411%24%44%
47599
Night
14%2310%24%44%
47024
SeeingDay
35%17%35%29%8%
5661
Night
3111%39%38%5%
15913

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
3212322346%68%
1611
16th to endDay
5%212313346%66%
1755
February1st to 15thDay
3112112346%69%
1751
16th to endDay
5%213322346%64%
1579
March1st to 15thDay
211212236%74%
1896
16th to endDay
11223335%75%
2112
April1st to 15thDay
2212212346%71%
2050
16th to endDay
111225%82%
2262
May1st to 15thDay
111123482%
2331
16th to endDay
11111222382%
2429
June1st to 15thDay
11111287%
2340
16th to endDay
11112386%
2340
July1st to 15thDay
2112212345%71%
2340
16th to endDay
3113435%5%6%8%56%
2467
August1st to 15thDay
121332335%7%66%
2315
16th to endDay
312223335%70%
2292
September1st to 15thDay
2212322235%70%
1995
16th to endDay
11111112384%
1904
October1st to 15thDay
211112235%75%
1815
16th to endDay
1111223479%
1760
November1st to 15thDay
111111233477%
1592
16th to endDay
211112137%75%
1620
December1st to 15thDay
3312323348%63%
1620
16th to endDay
421331236%6%63%
1728
January1st to 15thNight
3213223445%67%
2327
16th to endNight
6%212313335%65%
2466
February1st to 15thNight
2112213345%70%
2101
16th to endNight
6%312313347%62%
1895
March1st to 15thNight
2211212345%71%
2063
16th to endNight
2112313337%70%
2112
April1st to 15thNight
1112212235%74%
1895
16th to endNight
11122484%
1696
May1st to 15thNight
11122482%
1619
16th to endNight
1111113383%
1684
June1st to 15thNight
111122385%
1620
16th to endNight
1111387%
1620
July1st to 15thNight
11231345%5%69%
1620
16th to endNight
32233245%6%8%56%
1701
August1st to 15thNight
211212448%70%
1642
16th to endNight
212313436%69%
1910
September1st to 15thNight
11231335%7%69%
1965
16th to endNight
111112285%
1914
October1st to 15thNight
21121223477%
1815
16th to endNight
1121212480%
2112
November1st to 15thNight
211112335%76%
2265
16th to endNight
3122123377%
2340
December1st to 15thNight
4212222346%67%
2340
16th to endNight
6%312323335%65%
2496

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%2416%32%25%
1612
16th to endDay
19%26%16%30%24%
1755
February1st to 15thDay
16%25%16%27%32%
1751
16th to endDay
20%25%14%30%26%
1579
March1st to 15thDay
12%1211%29%41%
1896
16th to endDay
13%1313%31%36%
2112
April1st to 15thDay
15%139%28%41%
2050
16th to endDay
6%1110%26%53%
2262
May1st to 15thDay
8%1210%22%54%
2331
16th to endDay
9%116%20%60%
2432
June1st to 15thDay
6%1315%72%
2340
16th to endDay
6%137%80%
2340
July1st to 15thDay
14%25%10%15%51%
2201
16th to endDay
20%6%9%18%20%24%
2312
August1st to 15thDay
17%35%13%22%38%
2300
16th to endDay
17%2410%26%38%
2292
September1st to 15thDay
17%2412%18%43%
1995
16th to endDay
8%1419%65%
1904
October1st to 15thDay
11%238%25%49%
1815
16th to endDay
9%148%23%51%
1760
November1st to 15thDay
12%1312%29%40%
1592
16th to endDay
11%1412%31%37%
1620
December1st to 15thDay
21%25%20%28%21%
1620
16th to endDay
21%38%22%28%16%
1728
January1st to 15thNight
19%25%12%28%32%
2327
16th to endNight
21%1315%25%32%
2466
February1st to 15thNight
16%2414%25%36%
2112
16th to endNight
22%2412%25%32%
1895
March1st to 15thNight
14%149%26%42%
2063
16th to endNight
16%249%28%39%
2112
April1st to 15thNight
13%139%28%43%
1895
16th to endNight
6%139%24%56%
1696
May1st to 15thNight
8%127%24%55%
1620
16th to endNight
7%128%22%58%
1685
June1st to 15thNight
7%1315%70%
1620
16th to endNight
6%128%80%
1620
July1st to 15thNight
14%26%10%15%50%
1530
16th to endNight
20%49%18%19%27%
1593
August1st to 15thNight
13%2411%26%41%
1633
16th to endNight
16%3410%25%40%
1910
September1st to 15thNight
14%25%14%23%40%
1965
16th to endNight
7%11415%69%
1914
October1st to 15thNight
11%138%23%50%
1815
16th to endNight
10%138%19%57%
2112
November1st to 15thNight
12%139%25%48%
2265
16th to endNight
13%139%28%43%
2340
December1st to 15thNight
19%2413%30%29%
2340
16th to endNight
22%25%18%29%21%
2496

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
16%222%35%21%2
90
16th to endDay
25%17%29%31%13%
123
February1st to 15thDay
47%18%32%28%8%
266
16th to endDay
9%11%22%31%23%2
238
March1st to 15thDay
212%18%31%28%6%
270
16th to endDay
114%24%31%20%7%
288
April1st to 15thDay
7%11%24%30%16%8%
269
16th to endDay
216%32%29%16%2
270
May1st to 15thDay
29%27%34%20%5%
288
16th to endDay
5%28%40%19%5%
330
June1st to 15thDay
2323%41%23%5%
315
16th to endDay
113%42%30%10%
315
July1st to 15thDay
17%44%35%9%
305
16th to endDay
2333%45%14%
327
August1st to 15thDay
38%40%33%13%
315
16th to endDay
35%35%37%18%
332
September1st to 15thDay
2113%38%35%9%
315
16th to endDay
35%14%34%32%10%
288
October1st to 15thDay
27%20%35%26%8%
255
16th to endDay
336%27%46%13%
96
November1st to 15thDay
217%32%42%14%
90
16th to endDay
4420%36%31%3
90
December1st to 15thDay
1212%30%46%7%
90
16th to endDay
11%49%45%28%1
96
January1st to 15thNight
5%211%43%30%6%
720
16th to endNight
6%212%43%29%4
768
February1st to 15thNight
3212%47%31%2
704
16th to endNight
6%217%47%22%3
632
March1st to 15thNight
4317%40%29%4
720
16th to endNight
2216%44%30%3
768
April1st to 15thNight
2422%41%25%4
719
16th to endNight
1420%47%23%3
616
May1st to 15thNight
1315%42%34%2
540
16th to endNight
1316%43%31%3
563
June1st to 15thNight
1112%47%35%2
540
16th to endNight
16%38%49%4
540
July1st to 15thNight
1331%59%3
510
16th to endNight
3225%60%7%
564
August1st to 15thNight
2224%64%5%
561
16th to endNight
3218%65%9%
764
September1st to 15thNight
2330%55%8%
720
16th to endNight
28%31%50%6%
692
October1st to 15thNight
1113%42%38%2
660
16th to endNight
117%39%43%7%
704
November1st to 15thNight
28%45%35%6%
700
16th to endNight
410%38%38%7%
720
December1st to 15thNight
5%110%44%33%4
720
16th to endNight
8%213%43%27%4
768
Page generated at 2017-09-25 06:02:19. Version ac04

Copyright 2017 A. Danko


Crossroads OHV Area Clear Sky Chart | Charts Home