Cherry Road
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cherry Road clear sky chart from 2005-11-05 to 2018-10-27.

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
75%
17111
36%
51311
31%
17072
80%
17072
55%
24182

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%
779
33%
2522
31%
776
76%
776
46%
1223
January16th to endNight
66%
832
37%
2704
36%
832
73%
832
44%
1352
February1st to 15thNight
69%
758
35%
2375
30%
758
80%
758
51%
1116
February16th to endNight
66%
684
37%
2051
36%
684
73%
684
49%
1033
March1st to 15thNight
69%
780
38%
2152
31%
780
76%
780
56%
1068
March16th to endNight
73%
832
37%
2288
29%
832
80%
832
61%
1079
April1st to 15thNight
65%
766
33%
2130
21%
766
74%
766
57%
1036
April16th to endNight
68%
579
43%
1781
31%
579
79%
579
70%
701
May1st to 15thNight
73%
584
39%
1754
31%
584
78%
584
63%
748
May16th to endNight
76%
609
38%
1828
31%
609
80%
609
70%
741
June1st to 15thNight
83%
585
35%
1755
31%
585
84%
585
73%
708
June16th to endNight
87%
585
33%
1755
32%
585
87%
585
71%
713
July1st to 15thNight
84%
555
22%
1665
20%
555
84%
555
44%
872
July16th to endNight
82%
612
22%
1737
19%
579
83%
579
39%
959
August1st to 15thNight
87%
575
30%
1719
26%
572
87%
572
47%
869
August16th to endNight
87%
692
31%
1999
28%
692
88%
692
46%
1069
September1st to 15thNight
83%
780
33%
2145
29%
780
85%
780
53%
1112
September16th to endNight
85%
776
43%
2145
34%
776
89%
776
70%
952
October1st to 15thNight
76%
780
39%
2232
32%
780
81%
780
60%
1041
October16th to endNight
82%
816
43%
2448
39%
816
86%
816
66%
1056
November1st to 15thNight
78%
760
37%
2352
34%
760
84%
760
59%
1054
November16th to endNight
74%
780
42%
2535
41%
780
81%
780
57%
1094
December1st to 15thNight
72%
780
36%
2535
34%
780
77%
780
48%
1194
December16th to endNight
64%
832
35%
2704
32%
832
70%
832
40%
1392

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
3213323346%64%
52236
Night
3212223346%67%
51508
TransparencyDay
19%25%15%28%27%
51931
Night
18%25%15%28%29%
51314
SeeingDay
6%8%23%31%21%8%
6903
Night
4212%37%37%5%
17121

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%412422335%64%
1746
16th to endDay
6%5%12123345%62%
1872
February1st to 15thDay
45%24212345%62%
1813
16th to endDay
5%5%24423347%58%
1709
March1st to 15thDay
4313223346%64%
2138
16th to endDay
321331335%6%65%
2288
April1st to 15thDay
2212323337%66%
2145
16th to endDay
1212212246%71%
2451
May1st to 15thDay
2212223336%69%
2526
16th to endDay
1212213235%72%
2637
June1st to 15thDay
111123480%
2535
16th to endDay
11111122481%
2535
July1st to 15thDay
2213446%6%8%9%50%
2535
16th to endDay
4325%6%47%8%9%10%35%
2675
August1st to 15thDay
32145%35%5%8%9%48%
2485
16th to endDay
42134346%8%8%51%
2551
September1st to 15thDay
321442345%7%58%
2145
16th to endDay
211111225%77%
2145
October1st to 15thDay
321322333469%
2057
16th to endDay
1212212235%74%
2032
November1st to 15thDay
1211213346%70%
1834
16th to endDay
5%212111235%71%
1755
December1st to 15thDay
5%413323336%62%
1755
16th to endDay
7%5%32422347%55%
1872
January1st to 15thNight
431332445%5%62%
2522
16th to endNight
6%41332233463%
2704
February1st to 15thNight
3312212336%67%
2365
16th to endNight
5%312223347%61%
2051
March1st to 15thNight
3312312346%66%
2152
16th to endNight
2212212247%69%
2288
April1st to 15thNight
3111313336%67%
2130
16th to endNight
11112235%78%
1781
May1st to 15thNight
111212345%74%
1754
16th to endNight
11111122480%
1828
June1st to 15thNight
11111223380%
1755
16th to endNight
1112112383%
1755
July1st to 15thNight
1213435%6%6%8%56%
1755
16th to endNight
13145%37%6%9%12%44%
1845
August1st to 15thNight
22123345%7%12%55%
1728
16th to endNight
1212335%6%7%10%55%
1999
September1st to 15thNight
121342447%8%60%
2145
16th to endNight
21111122479%
2145
October1st to 15thNight
3212312235%71%
2232
16th to endNight
112222235%75%
2448
November1st to 15thNight
2212213346%69%
2352
16th to endNight
322212235%72%
2535
December1st to 15thNight
5%312123336%65%
2535
16th to endNight
7%413423446%57%
2704

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
23%1417%34%17%
1747
16th to endDay
23%16%18%32%16%
1872
February1st to 15thDay
23%26%18%28%21%
1813
16th to endDay
27%1419%30%17%
1709
March1st to 15thDay
20%1316%35%21%
2138
16th to endDay
18%1418%38%17%
2288
April1st to 15thDay
18%1417%32%25%
2145
16th to endDay
14%1312%35%31%
2451
May1st to 15thDay
15%1414%32%32%
2526
16th to endDay
13%15%9%32%38%
2640
June1st to 15thDay
9%15%26%56%
2535
16th to endDay
9%12319%63%
2535
July1st to 15thDay
24%6%9%16%15%27%
2396
16th to endDay
33%8%17%20%14%5%
2520
August1st to 15thDay
26%5%9%18%20%19%
2470
16th to endDay
24%5%10%18%24%14%
2551
September1st to 15thDay
22%48%16%23%24%
2145
16th to endDay
10%1210%36%37%
2145
October1st to 15thDay
17%2413%26%35%
2057
16th to endDay
12%1414%34%32%
2032
November1st to 15thDay
14%2419%35%24%
1834
16th to endDay
17%1217%30%30%
1755
December1st to 15thDay
25%28%21%25%16%
1755
16th to endDay
28%27%22%27%10%
1872
January1st to 15thNight
23%2419%32%17%
2522
16th to endNight
25%2417%31%19%
2704
February1st to 15thNight
19%26%18%29%23%
2376
16th to endNight
22%15%18%32%19%
2051
March1st to 15thNight
18%1315%34%26%
2152
16th to endNight
15%25%17%36%23%
2288
April1st to 15thNight
18%1414%32%28%
2130
16th to endNight
8%1311%37%37%
1781
May1st to 15thNight
13%1312%30%38%
1755
16th to endNight
10%39%32%43%
1829
June1st to 15thNight
10%1421%61%
1755
16th to endNight
10%1313%70%
1755
July1st to 15thNight
22%6%11%12%17%29%
1665
16th to endNight
26%7%16%22%18%8%
1737
August1st to 15thNight
20%6%11%18%20%22%
1719
16th to endNight
22%6%10%20%24%16%
1999
September1st to 15thNight
19%411%18%20%25%
2145
16th to endNight
10%218%36%40%
2145
October1st to 15thNight
16%1315%27%35%
2232
16th to endNight
12%15%11%27%41%
2448
November1st to 15thNight
15%2415%36%25%
2352
16th to endNight
15%2314%30%33%
2535
December1st to 15thNight
21%26%20%27%21%
2535
16th to endNight
28%27%20%29%11%
2704

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
22%214%31%25%2
135
16th to endDay
9%418%27%29%9%
144
February1st to 15thDay
7%7%25%32%17%8%
238
16th to endDay
11%23%27%24%12%1
290
March1st to 15thDay
7%15%28%26%16%5%
330
16th to endDay
5%17%31%25%16%3
352
April1st to 15thDay
8%17%33%22%11%5%
329
16th to endDay
7%22%34%22%8%3
318
May1st to 15thDay
5%15%34%26%14%4
348
16th to endDay
412%36%28%14%3
394
June1st to 15thDay
210%35%31%14%5%
375
16th to endDay
2220%45%19%9%
375
July1st to 15thDay
3117%40%26%10%
365
16th to endDay
6%6%37%28%20%
391
August1st to 15thDay
411%40%29%13%
359
16th to endDay
410%39%30%13%
396
September1st to 15thDay
5%120%35%30%7%
375
16th to endDay
7%6%18%36%24%7%
375
October1st to 15thDay
6%10%33%24%19%6%
287
16th to endDay
3314%26%34%17%
178
November1st to 15thDay
36%14%30%34%11%
135
16th to endDay
7%6%20%28%28%8%
135
December1st to 15thDay
5%5%14%31%38%2
135
16th to endDay
12%6%14%35%23%7%
144
January1st to 15thNight
6%215%46%23%5%
780
16th to endNight
8%316%41%28%1
832
February1st to 15thNight
6%216%43%27%2
764
16th to endNight
7%319%47%19%1
684
March1st to 15thNight
6%217%44%26%2
780
16th to endNight
3415%46%28%2
832
April1st to 15thNight
5%419%41%26%2
766
16th to endNight
15%23%39%27%3
579
May1st to 15thNight
2315%42%32%3
585
16th to endNight
2213%41%35%3
611
June1st to 15thNight
1111%41%41%3
585
16th to endNight
26%33%51%6%
585
July1st to 15thNight
2422%59%10%
555
16th to endNight
2212%60%20%
612
August1st to 15thNight
3217%62%13%
575
16th to endNight
2116%62%17%
692
September1st to 15thNight
35%23%56%11%
780
16th to endNight
27%34%47%6%
776
October1st to 15thNight
4211%43%36%2
780
16th to endNight
19%38%41%7%
816
November1st to 15thNight
311%45%33%4
760
16th to endNight
5%114%39%33%5%
780
December1st to 15thNight
8%212%44%29%1
780
16th to endNight
10%215%44%23%3
832
Page generated at 2018-10-28 05:41:04. Version ac04

Copyright 2018 A. Danko


Cherry Road Clear Sky Chart |Charts Home