Coyote Run Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Coyote Run Observatory 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
36%
16761
18%
48865
10%
16714
44%
16714
27%
31477

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
28%
975
14%
2648
6%
970
35%
970
22%
1850
January16th to endNight
25%
1040
15%
2704
5%
1040
32%
1040
20%
1969
February1st to 15thNight
25%
949
11%
2470
2%
945
30%
945
21%
1796
February16th to endNight
27%
753
18%
2015
5%
753
37%
753
25%
1358
March1st to 15thNight
34%
540
18%
1980
11%
540
44%
540
23%
1205
March16th to endNight
27%
576
14%
2112
9%
576
35%
576
16%
1450
April1st to 15thNight
28%
539
16%
1830
11%
539
38%
539
22%
1172
April16th to endNight
27%
540
18%
1637
11%
540
37%
540
20%
1159
May1st to 15thNight
38%
540
17%
1599
10%
540
44%
540
26%
1043
May16th to endNight
41%
563
15%
1498
5%
561
47%
561
30%
985
June1st to 15thNight
49%
540
14%
1440
5%
540
53%
540
33%
924
June16th to endNight
56%
540
19%
1440
7%
540
60%
540
47%
811
July1st to 15thNight
64%
510
19%
1360
8%
510
67%
510
49%
740
July16th to endNight
70%
564
23%
1553
17%
531
72%
531
48%
805
August1st to 15thNight
64%
539
22%
1610
21%
536
68%
536
41%
894
August16th to endNight
61%
573
24%
1767
25%
573
66%
573
38%
984
September1st to 15thNight
57%
540
25%
1827
23%
540
66%
540
39%
927
September16th to endNight
45%
540
25%
1983
18%
540
58%
540
32%
1056
October1st to 15thNight
36%
720
25%
2160
14%
720
45%
720
31%
1285
October16th to endNight
35%
768
22%
2304
11%
768
44%
768
27%
1427
November1st to 15thNight
33%
922
23%
2556
10%
922
43%
922
29%
1609
November16th to endNight
27%
975
19%
2730
8%
975
36%
975
25%
1798
December1st to 15thNight
22%
975
11%
2730
3%
975
29%
975
18%
2009
December16th to endNight
21%
1040
14%
2912
5%
1040
29%
1040
15%
2221

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
13%7%36%5%3445%7%38%
49214
Night
11%7%35%5%24447%43%
49045
Cloud CoverDay
13%7%36%5%3445%7%38%
49225
Night
11%7%35%5%24447%43%
49049
Cloud CoverDay
13%7%36%5%3445%7%38%
49223
Night
11%7%35%5%24447%43%
49049
TransparencyDay
44%5%14%22%11%1
48912
Night
40%5%14%24%13%1
48865
SeeingDay
15%7%30%29%13%3
6527
Night
15%8%34%30%11%
16762

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
9%10%5%8%8%35%46%7%29%
1617
16th to endDay
9%10%7%10%7%45%5%5%8%25%
1872
February1st to 15thDay
11%11%6%9%7%35%5%47%28%
1694
16th to endDay
12%7%49%7%26%5%5%6%32%
1470
March1st to 15thDay
13%10%6%8%5%24436%33%
1969
16th to endDay
19%10%36%5%2446%7%29%
2112
April1st to 15thDay
16%8%36%5%2446%7%34%
2118
16th to endDay
25%10%36%423345%28%
2322
May1st to 15thDay
20%7%35%5%3435%6%34%
2352
16th to endDay
17%5%25%5%35%45%7%37%
2617
June1st to 15thDay
14%5%25%4245%5%8%39%
2520
16th to endDay
7%424435%5%6%8%46%
2520
July1st to 15thDay
5%3235%35%6%6%9%49%
2520
16th to endDay
6%3134245%6%9%50%
2505
August1st to 15thDay
9%425%5%36%5%6%8%41%
2340
16th to endDay
11%5%25%42445%8%44%
2435
September1st to 15thDay
11%41342446%7%49%
2131
16th to endDay
11%42342345%7%50%
1965
October1st to 15thDay
15%6%24433345%46%
1800
16th to endDay
13%8%35%423345%44%
1920
November1st to 15thDay
10%5%35%5%33446%45%
1631
16th to endDay
13%9%35%5%34338%39%
1560
December1st to 15thDay
13%8%411%8%5%5%445%27%
1560
16th to endDay
16%12%5%8%8%2345%7%24%
1664
January1st to 15thNight
8%8%46%7%35%5%7%8%34%
2648
16th to endNight
11%10%47%6%35%45%7%32%
2704
February1st to 15thNight
11%12%5%6%6%34346%33%
2467
16th to endNight
9%7%36%6%35%447%40%
2015
March1st to 15thNight
13%6%27%423347%43%
1968
16th to endNight
14%9%5%7%5%33345%35%
2112
April1st to 15thNight
16%6%25%5%24446%41%
1830
16th to endNight
20%8%36%5%33345%36%
1637
May1st to 15thNight
15%5%245%24447%44%
1599
16th to endNight
13%5%2442445%10%40%
1496
June1st to 15thNight
9%424425%5%7%9%43%
1440
16th to endNight
6%21331345%9%57%
1440
July1st to 15thNight
321321445%10%60%
1440
16th to endNight
32132245%5%10%58%
1660
August1st to 15thNight
432442346%7%55%
1620
16th to endNight
8%414412436%57%
1767
September1st to 15thNight
9%412322336%60%
1827
16th to endNight
9%414333447%53%
1983
October1st to 15thNight
14%5%2442234451%
2160
16th to endNight
15%6%24313345%47%
2304
November1st to 15thNight
11%6%25%5%23345%48%
2556
16th to endNight
10%8%35%5%24346%43%
2730
December1st to 15thNight
12%10%47%6%35%45%6%31%
2730
16th to endNight
17%10%5%9%6%34445%28%
2912

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
9%10%5%8%8%35%46%7%29%
1617
16th to endDay
9%10%7%10%8%45%5%5%7%25%
1872
February1st to 15thDay
11%11%5%9%7%35%447%28%
1694
16th to endDay
12%7%39%7%26%5%5%6%32%
1470
March1st to 15thDay
13%10%6%8%5%24437%33%
1980
16th to endDay
19%10%36%5%2445%7%29%
2112
April1st to 15thDay
16%8%36%5%2446%7%34%
2118
16th to endDay
25%10%36%424345%28%
2322
May1st to 15thDay
20%7%35%5%3435%6%34%
2352
16th to endDay
17%6%25%5%25%45%7%37%
2617
June1st to 15thDay
14%5%25%4345%5%8%39%
2520
16th to endDay
7%424435%5%6%8%46%
2520
July1st to 15thDay
5%323435%6%6%9%49%
2520
16th to endDay
6%3134245%6%9%50%
2505
August1st to 15thDay
9%425%5%35%5%6%9%40%
2340
16th to endDay
11%5%2442445%8%44%
2435
September1st to 15thDay
11%41342445%7%49%
2131
16th to endDay
11%42342335%7%50%
1965
October1st to 15thDay
15%6%14433335%46%
1800
16th to endDay
13%8%35%423345%44%
1920
November1st to 15thDay
10%6%36%5%33446%45%
1631
16th to endDay
13%9%35%5%34347%39%
1560
December1st to 15thDay
13%8%411%8%5%5%446%27%
1560
16th to endDay
16%12%5%8%8%2345%7%23%
1664
January1st to 15thNight
8%8%46%6%35%5%6%8%33%
2648
16th to endNight
10%10%47%6%35%45%7%32%
2704
February1st to 15thNight
10%13%5%6%6%34346%34%
2460
16th to endNight
9%7%36%6%35%447%40%
2015
March1st to 15thNight
13%6%27%423347%43%
1980
16th to endNight
14%10%5%7%5%3334435%
2112
April1st to 15thNight
16%6%25%434446%42%
1830
16th to endNight
20%8%36%5%33345%36%
1637
May1st to 15thNight
15%5%245%24447%44%
1598
16th to endNight
13%4344345%5%10%41%
1496
June1st to 15thNight
9%424435%6%7%9%43%
1440
16th to endNight
6%21331345%8%58%
1440
July1st to 15thNight
32132145%5%9%60%
1440
16th to endNight
32132245%5%10%59%
1660
August1st to 15thNight
432442345%7%55%
1620
16th to endNight
8%414422436%57%
1767
September1st to 15thNight
9%412323336%60%
1827
16th to endNight
9%414323447%53%
1983
October1st to 15thNight
14%5%2442233451%
2160
16th to endNight
15%6%23313345%47%
2304
November1st to 15thNight
11%6%25%5%2335%5%47%
2556
16th to endNight
10%8%35%424346%43%
2730
December1st to 15thNight
12%10%47%6%35%45%6%31%
2730
16th to endNight
17%10%5%8%6%34445%28%
2912

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
9%10%5%8%7%35%46%7%29%
1617
16th to endDay
10%10%6%10%7%46%448%24%
1872
February1st to 15thDay
12%10%5%10%7%34447%28%
1694
16th to endDay
12%7%49%7%26%5%46%32%
1470
March1st to 15thDay
13%10%6%8%5%24336%33%
1980
16th to endDay
19%10%36%5%3446%6%29%
2110
April1st to 15thDay
16%8%36%5%3446%6%34%
2118
16th to endDay
25%10%36%423445%29%
2322
May1st to 15thDay
20%6%35%5%34346%34%
2352
16th to endDay
17%5%25%5%25%45%7%37%
2617
June1st to 15thDay
15%5%25%5%3445%8%39%
2520
16th to endDay
8%414435%5%6%8%46%
2520
July1st to 15thDay
5%314426%5%6%9%49%
2520
16th to endDay
6%314425%6%6%9%50%
2505
August1st to 15thDay
9%425%6%35%5%6%9%41%
2340
16th to endDay
11%5%245%2445%8%44%
2435
September1st to 15thDay
11%41342446%7%49%
2131
16th to endDay
11%424423447%50%
1965
October1st to 15thDay
15%6%24424345%46%
1800
16th to endDay
14%9%35%413345%44%
1920
November1st to 15thDay
10%5%36%5%24446%45%
1631
16th to endDay
13%9%36%5%34338%39%
1560
December1st to 15thDay
13%9%410%8%5%5%436%27%
1560
16th to endDay
16%12%5%8%8%2345%7%24%
1664
January1st to 15thNight
8%8%46%6%35%6%7%8%33%
2648
16th to endNight
11%10%47%5%35%36%7%32%
2704
February1st to 15thNight
10%13%5%6%7%34446%34%
2460
16th to endNight
9%8%45%6%35%447%40%
2015
March1st to 15thNight
13%6%26%5%13447%43%
1980
16th to endNight
14%10%47%5%3434435%
2112
April1st to 15thNight
16%6%25%424446%42%
1830
16th to endNight
20%8%36%5%24335%36%
1637
May1st to 15thNight
15%5%24433447%44%
1598
16th to endNight
13%5%2442445%10%41%
1496
June1st to 15thNight
9%424426%6%7%8%44%
1440
16th to endNight
6%21342335%9%57%
1440
July1st to 15thNight
32321445%9%60%
1440
16th to endNight
32132245%5%10%59%
1660
August1st to 15thNight
5%3244145%5%7%55%
1620
16th to endNight
8%414423336%57%
1767
September1st to 15thNight
9%313223336%60%
1827
16th to endNight
8%414423447%53%
1983
October1st to 15thNight
14%5%14423335%51%
2160
16th to endNight
15%6%24312446%47%
2304
November1st to 15thNight
11%6%25%5%24346%47%
2556
16th to endNight
11%8%45%424446%43%
2730
December1st to 15thNight
12%10%48%7%35%45%6%31%
2730
16th to endNight
17%10%5%8%6%34445%28%
2912

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
51%5%14%18%9%
1618
16th to endDay
57%6%14%16%4
1872
February1st to 15thDay
56%5%13%17%6%
1695
16th to endDay
50%5%15%17%8%1
1470
March1st to 15thDay
52%415%20%6%
1980
16th to endDay
53%6%15%19%4
2112
April1st to 15thDay
47%6%13%22%8%1
2118
16th to endDay
56%5%11%19%7%
2322
May1st to 15thDay
50%5%12%22%8%
2352
16th to endDay
45%6%14%19%12%1
2621
June1st to 15thDay
42%6%15%23%11%
2520
16th to endDay
32%7%16%26%14%2
2520
July1st to 15thDay
30%8%16%28%13%3
2371
16th to endDay
28%7%17%29%15%2
2349
August1st to 15thDay
38%6%15%26%10%1
2326
16th to endDay
36%6%13%27%14%2
2435
September1st to 15thDay
32%7%15%27%16%
2131
16th to endDay
33%5%12%32%14%
1965
October1st to 15thDay
40%411%23%19%1
1800
16th to endDay
41%414%24%13%1
1920
November1st to 15thDay
38%413%23%18%1
1631
16th to endDay
44%5%17%21%10%
1560
December1st to 15thDay
58%5%13%12%7%1
1560
16th to endDay
59%412%15%7%
1664
January1st to 15thNight
44%7%14%21%11%
2648
16th to endNight
49%5%17%18%7%
2704
February1st to 15thNight
50%413%20%9%
2470
16th to endNight
43%415%23%11%2
2015
March1st to 15thNight
40%416%25%10%1
1980
16th to endNight
51%412%22%6%
2112
April1st to 15thNight
42%5%12%24%12%1
1830
16th to endNight
50%5%9%20%11%2
1637
May1st to 15thNight
39%7%13%24%14%1
1599
16th to endNight
38%6%17%22%13%2
1498
June1st to 15thNight
33%8%18%24%13%1
1440
16th to endNight
24%5%16%29%21%3
1440
July1st to 15thNight
19%7%17%33%17%5%
1360
16th to endNight
19%7%16%33%19%4
1553
August1st to 15thNight
26%6%15%31%17%2
1610
16th to endNight
28%5%13%30%17%4
1767
September1st to 15thNight
25%414%31%21%2
1827
16th to endNight
30%413%31%18%1
1983
October1st to 15thNight
36%311%27%19%2
2160
16th to endNight
37%5%14%24%16%1
2304
November1st to 15thNight
37%412%24%18%1
2556
16th to endNight
41%5%15%24%11%1
2730
December1st to 15thNight
52%5%15%18%7%
2730
16th to endNight
57%5%11%15%9%
2912

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%9%37%26%8%
135
16th to endDay
12%9%39%33%41
144
February1st to 15thDay
12%16%36%33%1
130
16th to endDay
20%11%34%23%9%
81
March1st to 15thDay
23%14%38%22%1
90
16th to endDay
34%7%27%25%6%
96
April1st to 15thDay
21%8%35%27%7%
237
16th to endDay
30%15%25%19%6%2
432
May1st to 15thDay
22%13%28%28%5%2
468
16th to endDay
20%8%30%24%13%2
517
June1st to 15thDay
15%429%31%14%3
495
16th to endDay
7%7%35%33%12%3
495
July1st to 15thDay
6%129%34%22%5%
475
16th to endDay
7%224%38%21%5%
515
August1st to 15thDay
8%222%35%26%3
493
16th to endDay
16%420%30%22%6%
475
September1st to 15thDay
10%329%32%19%5%
286
16th to endDay
15%7%31%25%16%2
135
October1st to 15thDay
16%9%35%22%12%2
135
16th to endDay
20%12%36%20%11%
144
November1st to 15thDay
6%11%39%31%9%2
135
16th to endDay
33%12%32%16%5%
135
December1st to 15thDay
16%13%50%13%5%
135
16th to endDay
26%19%38%13%2
144
January1st to 15thNight
13%12%38%26%7%1
975
16th to endNight
17%10%37%29%5%
1040
February1st to 15thNight
17%11%36%26%6%
950
16th to endNight
13%10%41%24%8%1
753
March1st to 15thNight
17%7%35%29%9%
540
16th to endNight
19%10%36%25%7%
576
April1st to 15thNight
20%9%37%26%6%
539
16th to endNight
23%9%34%21%9%1
540
May1st to 15thNight
16%8%35%29%10%
540
16th to endNight
16%6%29%33%13%
563
June1st to 15thNight
10%429%41%14%
540
16th to endNight
6%330%45%13%
540
July1st to 15thNight
4126%41%24%1
510
16th to endNight
3121%47%24%1
564
August1st to 15thNight
5%121%42%26%2
539
16th to endNight
11%319%39%22%4
573
September1st to 15thNight
12%125%36%21%2
540
16th to endNight
10%6%34%30%17%1
540
October1st to 15thNight
16%8%34%28%11%
720
16th to endNight
19%9%32%30%8%
768
November1st to 15thNight
15%11%35%26%10%
922
16th to endNight
14%14%40%23%7%
975
December1st to 15thNight
17%11%41%25%4
975
16th to endNight
23%9%37%22%6%
1040
Page generated at 2018-02-15 09:58:41. Version ac04

Copyright 2018 A. Danko


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