Revall's Coyote Creek Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Revall's Coyote Creek Observatory clear sky chart from 2005-11-05 to 2017-10-06.

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
35%
16205
15%
47045
8%
16160
41%
16160
22%
32325

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
24%
900
10%
2506
4%
895
30%
895
16%
1890
January16th to endNight
20%
960
13%
2688
3%
960
28%
960
16%
2022
February1st to 15thNight
22%
845
14%
2314
4%
842
29%
842
19%
1687
February16th to endNight
26%
631
15%
1893
8%
631
32%
631
16%
1385
March1st to 15thNight
29%
720
16%
2160
8%
720
35%
720
21%
1458
March16th to endNight
33%
642
18%
2019
13%
642
42%
642
21%
1358
April1st to 15thNight
29%
539
13%
1797
8%
539
37%
539
18%
1253
April16th to endNight
35%
540
17%
1671
9%
540
43%
540
22%
1132
May1st to 15thNight
35%
540
13%
1515
7%
540
41%
540
20%
1091
May16th to endNight
41%
562
14%
1498
6%
561
48%
561
29%
1001
June1st to 15thNight
44%
540
11%
1440
6%
540
47%
540
27%
969
June16th to endNight
48%
540
11%
1440
6%
540
50%
540
30%
964
July1st to 15thNight
61%
510
14%
1360
8%
510
63%
510
41%
808
July16th to endNight
59%
564
17%
1417
9%
531
64%
531
43%
824
August1st to 15thNight
59%
539
21%
1467
14%
536
64%
536
37%
890
August16th to endNight
57%
573
20%
1864
18%
573
62%
573
29%
1114
September1st to 15thNight
55%
546
24%
1806
20%
546
63%
546
33%
1022
September16th to endNight
49%
717
19%
1980
14%
717
54%
717
31%
1242
October1st to 15thNight
36%
684
19%
1972
12%
684
43%
684
24%
1308
October16th to endNight
29%
704
12%
2285
6%
704
37%
704
17%
1621
November1st to 15thNight
28%
700
18%
2276
11%
700
38%
700
19%
1533
November16th to endNight
31%
849
14%
2469
8%
849
36%
849
16%
1817
December1st to 15thNight
20%
900
11%
2520
3%
900
28%
900
17%
1859
December16th to endNight
20%
960
13%
2688
3%
960
27%
960
15%
2077

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
14%8%36%5%35%5%5%7%34%
48163
Night
14%8%36%5%34446%38%
47213
Cloud CoverDay
14%8%36%6%35%45%7%34%
48172
Night
14%8%36%5%3445%7%37%
47218
TransparencyDay
47%7%13%21%10%
47849
Night
45%6%13%22%10%1
47045
SeeingDay
17%10%29%25%12%4
6192
Night
18%7%31%30%11%1
16206

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
12%11%5%9%6%45%5%5%6%27%
1432
16th to endDay
15%11%5%9%7%4445%5%26%
1536
February1st to 15thDay
11%11%5%8%6%3445%7%31%
1546
16th to endDay
13%12%48%7%35%446%28%
1580
March1st to 15thDay
13%12%47%5%345%5%6%32%
1790
16th to endDay
17%11%47%6%245%35%31%
2215
April1st to 15thDay
18%11%46%5%24346%30%
2151
16th to endDay
19%8%35%5%25%45%7%32%
2289
May1st to 15thDay
17%8%36%7%35%346%32%
2433
16th to endDay
13%5%25%5%35%45%8%40%
2617
June1st to 15thDay
15%5%25%5%35%448%38%
2520
16th to endDay
12%6%25%5%46%5%6%9%35%
2520
July1st to 15thDay
10%3245%36%6%7%9%39%
2520
16th to endDay
9%425%5%45%5%6%9%41%
2655
August1st to 15thDay
8%5%25%5%35%5%7%9%40%
2482
16th to endDay
14%5%24435%5%5%7%41%
2336
September1st to 15thDay
12%5%25%5%34448%42%
2142
16th to endDay
11%425%5%46%7%5%9%37%
1980
October1st to 15thDay
19%6%26%5%2435%7%37%
1784
16th to endDay
22%8%38%6%45%445%26%
1587
November1st to 15thDay
14%10%36%6%35%5%5%7%32%
1582
16th to endDay
17%10%5%6%5%345%5%8%25%
1490
December1st to 15thDay
17%11%5%7%5%33336%32%
1440
16th to endDay
20%13%49%6%35%445%21%
1536
January1st to 15thNight
15%10%5%8%5%25%5%46%29%
2506
16th to endNight
11%12%6%8%6%45%347%28%
2688
February1st to 15thNight
11%11%5%7%6%3345%6%33%
2312
16th to endNight
13%12%48%7%3445%5%30%
1893
March1st to 15thNight
14%8%36%5%33445%41%
2147
16th to endNight
15%8%34435%5%5%5%39%
2019
April1st to 15thNight
21%7%35%43435%5%34%
1797
16th to endNight
19%7%26%433347%37%
1671
May1st to 15thNight
19%6%26%5%35%5%5%7%32%
1515
16th to endNight
12%5%245%26%5%5%7%42%
1496
June1st to 15thNight
13%7%26%41445%7%41%
1440
16th to endNight
13%415%435%5%6%9%40%
1440
July1st to 15thNight
8%212425%5%48%53%
1440
16th to endNight
6%32332435%8%55%
1513
August1st to 15thNight
6%324425%45%8%51%
1476
16th to endNight
11%4145%24346%51%
1864
September1st to 15thNight
9%5%24422345%53%
1806
16th to endNight
14%5%1432335%8%46%
1980
October1st to 15thNight
15%7%25%5%23348%40%
1972
16th to endNight
18%9%27%5%34446%33%
2285
November1st to 15thNight
16%8%35%5%2445%7%36%
2276
16th to endNight
16%8%45%5%35%5%5%7%30%
2469
December1st to 15thNight
17%11%46%5%24346%32%
2520
16th to endNight
19%13%6%7%5%24345%28%
2688

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
11%12%5%10%6%345%5%6%27%
1432
16th to endDay
14%12%49%7%5%445%5%25%
1536
February1st to 15thDay
10%12%5%8%5%35%45%7%31%
1546
16th to endDay
13%12%5%8%7%44446%28%
1580
March1st to 15thDay
12%12%47%5%345%47%31%
1800
16th to endDay
16%11%47%7%2444431%
2214
April1st to 15thDay
18%11%47%5%3435%6%30%
2151
16th to endDay
19%9%35%5%35%45%6%32%
2289
May1st to 15thDay
17%8%37%7%34446%32%
2433
16th to endDay
11%6%25%5%35%45%8%40%
2617
June1st to 15thDay
14%6%35%5%35%45%7%38%
2520
16th to endDay
11%6%26%6%36%5%6%9%35%
2520
July1st to 15thDay
9%325%5%36%6%7%9%39%
2520
16th to endDay
8%426%5%36%5%6%9%40%
2655
August1st to 15thDay
8%5%25%6%35%5%6%9%40%
2482
16th to endDay
13%5%245%25%5%6%8%40%
2336
September1st to 15thDay
11%5%26%5%345%47%41%
2142
16th to endDay
10%5%25%6%36%6%6%9%37%
1980
October1st to 15thDay
18%6%36%42435%6%36%
1784
16th to endDay
21%9%38%7%44446%26%
1587
November1st to 15thDay
14%9%36%6%35%5%5%6%32%
1582
16th to endDay
17%10%5%7%6%35%5%5%9%24%
1490
December1st to 15thDay
16%11%5%7%6%24445%32%
1440
16th to endDay
20%12%5%8%7%45%5%4421%
1536
January1st to 15thNight
15%10%5%8%6%35%5%5%5%29%
2506
16th to endNight
11%12%6%8%6%44347%27%
2688
February1st to 15thNight
11%12%5%7%6%34447%32%
2305
16th to endNight
13%12%5%8%7%3435%6%29%
1893
March1st to 15thNight
15%8%36%4345%45%40%
2160
16th to endNight
15%8%44435%5%5%6%38%
2019
April1st to 15thNight
20%7%46%43435%5%34%
1797
16th to endNight
19%7%345%2435%7%37%
1671
May1st to 15thNight
18%6%27%6%25%5%5%7%31%
1514
16th to endNight
12%4245%26%5%6%7%41%
1496
June1st to 15thNight
13%6%26%42445%7%41%
1440
16th to endNight
12%425%425%5%6%9%40%
1440
July1st to 15thNight
8%212425%46%8%53%
1440
16th to endNight
5%41441445%8%55%
1513
August1st to 15thNight
6%4145%25%45%8%50%
1476
16th to endNight
10%324434345%51%
1864
September1st to 15thNight
8%5%245%23346%53%
1806
16th to endNight
13%5%24423348%45%
1980
October1st to 15thNight
15%7%25%5%2335%7%40%
1972
16th to endNight
17%9%37%5%3445%7%32%
2285
November1st to 15thNight
15%8%35%5%33448%35%
2276
16th to endNight
16%8%46%5%35%5%5%7%29%
2469
December1st to 15thNight
16%11%47%5%3435%6%31%
2520
16th to endNight
18%13%6%7%5%24335%27%
2688

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
56%7%9%17%9%
1433
16th to endDay
58%6%14%14%6%
1536
February1st to 15thDay
50%7%15%18%7%1
1548
16th to endDay
56%5%11%17%7%
1580
March1st to 15thDay
51%7%13%18%7%1
1800
16th to endDay
55%5%11%19%6%1
2215
April1st to 15thDay
53%5%11%19%8%1
2151
16th to endDay
50%6%9%18%13%1
2289
May1st to 15thDay
52%5%10%19%10%1
2433
16th to endDay
41%7%12%23%14%1
2621
June1st to 15thDay
43%6%12%23%12%
2520
16th to endDay
44%8%15%19%11%
2520
July1st to 15thDay
35%8%15%25%12%1
2371
16th to endDay
37%8%13%21%16%1
2488
August1st to 15thDay
36%9%13%26%12%1
2467
16th to endDay
39%7%15%24%12%
2336
September1st to 15thDay
39%7%14%27%11%
2142
16th to endDay
40%9%17%26%6%
1980
October1st to 15thDay
46%6%14%25%7%
1784
16th to endDay
58%6%11%17%5%
1587
November1st to 15thDay
50%6%11%20%11%
1582
16th to endDay
55%8%15%15%5%
1490
December1st to 15thDay
54%412%20%7%
1440
16th to endDay
63%6%11%13%4
1536
January1st to 15thNight
54%6%11%18%7%
2506
16th to endNight
55%5%11%19%7%
2688
February1st to 15thNight
51%5%11%20%8%1
2314
16th to endNight
54%5%12%18%8%1
1893
March1st to 15thNight
45%6%11%22%12%1
2160
16th to endNight
45%6%12%23%10%1
2019
April1st to 15thNight
50%5%10%20%11%1
1797
16th to endNight
47%412%19%13%2
1671
May1st to 15thNight
50%6%10%20%11%1
1515
16th to endNight
39%6%13%24%15%
1498
June1st to 15thNight
41%5%12%23%15%1
1440
16th to endNight
38%7%16%23%12%1
1440
July1st to 15thNight
26%7%13%32%16%2
1360
16th to endNight
25%7%19%28%16%2
1417
August1st to 15thNight
29%8%14%32%14%1
1467
16th to endNight
34%7%12%26%15%3
1864
September1st to 15thNight
31%5%12%35%14%
1806
16th to endNight
36%5%17%30%9%
1980
October1st to 15thNight
43%5%12%27%9%1
1972
16th to endNight
50%7%14%19%7%
2285
November1st to 15thNight
46%6%12%22%11%
2276
16th to endNight
52%7%15%18%6%
2469
December1st to 15thNight
53%6%13%19%7%
2520
16th to endNight
59%5%12%16%6%
2688

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
20%12%38%24%4
90
16th to endDay
30%6%31%25%5%2
96
February1st to 15thDay
14%24%41%15%31
90
16th to endDay
28%9%38%18%31
81
March1st to 15thDay
14%18%38%20%7%
90
16th to endDay
27%10%23%26%10%1
255
April1st to 15thDay
24%8%30%25%10%1
270
16th to endDay
26%9%28%19%12%3
270
May1st to 15thDay
22%16%28%18%10%3
390
16th to endDay
17%13%33%23%7%4
517
June1st to 15thDay
17%11%30%26%10%3
495
16th to endDay
15%8%31%28%10%4
495
July1st to 15thDay
13%6%27%32%14%6%
475
16th to endDay
8%7%33%28%15%7%
515
August1st to 15thDay
11%5%24%30%19%8%
455
16th to endDay
18%5%18%25%22%9%
332
September1st to 15thDay
13%422%26%22%10%
315
16th to endDay
9%9%25%32%18%4
314
October1st to 15thDay
21%11%27%24%12%2
185
16th to endDay
23%15%35%21%3
96
November1st to 15thDay
5%13%42%24%11%3
90
16th to endDay
22%18%27%17%13%
90
December1st to 15thDay
21%12%47%13%32
90
16th to endDay
27%20%36%14%1
96
January1st to 15thNight
19%10%37%26%6%
900
16th to endNight
18%8%39%24%7%
960
February1st to 15thNight
19%8%39%26%6%
845
16th to endNight
19%12%31%28%6%
631
March1st to 15thNight
17%11%35%27%8%
720
16th to endNight
18%8%34%28%9%
642
April1st to 15thNight
23%8%32%28%6%
539
16th to endNight
23%6%29%30%9%
540
May1st to 15thNight
22%8%28%31%8%
540
16th to endNight
15%5%32%34%11%1
563
June1st to 15thNight
17%5%25%38%12%
540
16th to endNight
14%426%40%13%1
540
July1st to 15thNight
8%123%45%20%
510
16th to endNight
7%326%41%20%1
564
August1st to 15thNight
8%122%39%25%2
539
16th to endNight
12%321%38%22%2
573
September1st to 15thNight
10%225%31%25%4
546
16th to endNight
17%5%23%32%19%2
717
October1st to 15thNight
19%7%30%27%14%
684
16th to endNight
23%9%31%24%10%
704
November1st to 15thNight
19%10%35%25%7%
700
16th to endNight
20%13%28%28%7%
849
December1st to 15thNight
23%9%40%20%6%
900
16th to endNight
25%8%34%24%5%1
960
Page generated at 2017-10-07 14:07:51. Version ac04

Copyright 2017 A. Danko


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