Yoder Observing Site
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Yoder Observing Site clear sky chart from 2005-11-05 to 2017-09-17.

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
54%
15557
23%
46945
17%
15515
60%
15515
30%
28987

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
34%
718
23%
2327
13%
716
48%
716
26%
1415
January16th to endNight
35%
768
25%
2421
15%
768
47%
768
26%
1513
February1st to 15thNight
38%
704
26%
2108
13%
700
51%
700
30%
1272
February16th to endNight
35%
631
26%
1893
13%
631
47%
631
30%
1150
March1st to 15thNight
40%
720
27%
2046
14%
720
51%
720
34%
1216
March16th to endNight
45%
768
23%
2112
13%
768
52%
768
33%
1292
April1st to 15thNight
50%
677
25%
1935
19%
677
56%
677
35%
1155
April16th to endNight
56%
540
29%
1714
21%
540
66%
540
38%
939
May1st to 15thNight
61%
539
24%
1620
17%
539
67%
539
35%
956
May16th to endNight
69%
561
22%
1682
18%
561
71%
561
35%
1015
June1st to 15thNight
68%
540
15%
1620
13%
540
69%
540
26%
1090
June16th to endNight
74%
540
17%
1620
16%
540
74%
540
29%
1044
July1st to 15thNight
74%
510
10%
1530
9%
510
74%
510
25%
1031
July16th to endNight
75%
564
13%
1595
13%
531
75%
531
26%
1080
August1st to 15thNight
76%
539
15%
1666
16%
536
75%
536
26%
1105
August16th to endNight
68%
581
16%
1918
18%
581
68%
581
20%
1314
September1st to 15thNight
67%
720
17%
1980
16%
720
67%
720
26%
1336
September16th to endNight
60%
665
19%
1837
15%
665
63%
665
25%
1245
October1st to 15thNight
61%
660
31%
1818
26%
660
66%
660
38%
1088
October16th to endNight
58%
704
33%
2112
29%
704
66%
704
39%
1154
November1st to 15thNight
57%
700
31%
2215
26%
700
66%
700
38%
1199
November16th to endNight
46%
720
28%
2340
21%
720
58%
720
33%
1323
December1st to 15thNight
44%
720
25%
2340
19%
720
53%
720
28%
1418
December16th to endNight
40%
768
22%
2496
18%
768
47%
768
22%
1637

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
11%5%25%5%35%45%7%42%
47820
Night
11%42443445%7%46%
47148
TransparencyDay
39%7%11%17%17%6%
47521
Night
35%6%11%17%19%8%
46951
SeeingDay
12%314%22%26%19%
5439
Night
12%421%31%25%4
15562

By Month

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
15%424424435%47%
1611
16th to endDay
15%6%24424446%44%
1800
February1st to 15thDay
13%5%35%424445%46%
1750
16th to endDay
15%6%23423245%48%
1580
March1st to 15thDay
12%5%25%5%2435%6%47%
1914
16th to endDay
13%425%424446%47%
2111
April1st to 15thDay
12%424434347%47%
2023
16th to endDay
8%313334347%54%
2244
May1st to 15thDay
8%5%245%25%35%7%48%
2331
16th to endDay
6%425%6%36%5%6%8%43%
2431
June1st to 15thDay
9%5%25%7%47%6%7%9%34%
2340
16th to endDay
5%315%6%47%6%9%11%38%
2340
July1st to 15thDay
8%5%27%9%5%7%7%8%10%27%
2340
16th to endDay
7%425%7%5%8%8%7%10%30%
2465
August1st to 15thDay
10%5%26%7%5%7%6%9%11%26%
2280
16th to endDay
13%7%36%7%46%6%6%8%28%
2271
September1st to 15thDay
11%5%26%5%36%5%6%10%36%
1980
16th to endDay
15%7%36%6%35%45%5%36%
1829
October1st to 15thDay
15%413322336%52%
1812
16th to endDay
11%214313336%59%
1760
November1st to 15thDay
11%423224345%55%
1640
16th to endDay
13%4245%24336%50%
1620
December1st to 15thDay
15%5%14424337%45%
1620
16th to endDay
21%7%36%5%23335%37%
1728
January1st to 15thNight
14%6%24433247%46%
2327
16th to endNight
18%425%32433447%
2421
February1st to 15thNight
14%5%2442235%5%49%
2103
16th to endNight
13%5%24323446%48%
1893
March1st to 15thNight
10%424432447%51%
2046
16th to endNight
11%5%24423347%51%
2112
April1st to 15thNight
11%314423447%51%
1935
16th to endNight
7%32441446%7%54%
1714
May1st to 15thNight
5%4245%25%5%5%7%50%
1619
16th to endNight
6%4244345%6%9%47%
1682
June1st to 15thNight
7%5%25%6%5%6%6%8%12%34%
1620
16th to endNight
3426%6%37%6%9%11%39%
1620
July1st to 15thNight
6%325%5%47%7%9%12%34%
1620
16th to endNight
6%3246%46%8%9%12%34%
1703
August1st to 15thNight
5%425%6%47%7%7%12%36%
1677
16th to endNight
10%5%25%6%36%6%7%12%32%
1918
September1st to 15thNight
10%5%25%5%45%5%6%8%39%
1980
16th to endNight
10%7%36%5%35%5%5%8%38%
1837
October1st to 15thNight
12%413323346%54%
1818
16th to endNight
9%313322345%58%
2112
November1st to 15thNight
9%413313345%58%
2215
16th to endNight
13%324313335%54%
2340
December1st to 15thNight
13%4245%3345%6%47%
2340
16th to endNight
18%7%25%424447%38%
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
39%47%14%25%7%
1612
16th to endDay
39%47%15%22%10%
1800
February1st to 15thDay
39%36%17%22%10%
1752
16th to endDay
37%46%16%25%9%
1580
March1st to 15thDay
37%5%8%18%20%9%
1914
16th to endDay
37%5%10%16%23%6%
2112
April1st to 15thDay
37%47%20%21%9%
2023
16th to endDay
28%5%10%23%22%9%
2244
May1st to 15thDay
34%7%11%19%20%6%
2331
16th to endDay
35%8%13%24%14%3
2435
June1st to 15thDay
42%9%16%19%10%1
2340
16th to endDay
35%10%17%18%15%2
2340
July1st to 15thDay
46%11%21%13%5%1
2201
16th to endDay
42%13%18%17%7%
2310
August1st to 15thDay
45%11%19%14%7%
2267
16th to endDay
50%9%14%13%9%1
2271
September1st to 15thDay
40%10%14%14%16%3
1980
16th to endDay
48%7%6%17%15%5%
1829
October1st to 15thDay
34%39%19%22%10%
1812
16th to endDay
27%36%15%28%17%
1760
November1st to 15thDay
30%36%17%25%16%
1640
16th to endDay
35%47%13%24%13%
1620
December1st to 15thDay
39%5%9%16%20%9%
1620
16th to endDay
49%37%16%15%7%
1728
January1st to 15thNight
39%36%16%25%8%
2327
16th to endNight
41%25%13%24%11%
2421
February1st to 15thNight
36%35%17%22%13%
2112
16th to endNight
36%46%15%22%14%
1893
March1st to 15thNight
32%49%20%22%10%
2046
16th to endNight
34%410%16%23%9%
2112
April1st to 15thNight
32%48%20%21%12%
1935
16th to endNight
27%5%11%22%21%11%
1714
May1st to 15thNight
30%7%12%19%22%7%
1620
16th to endNight
30%8%15%23%15%6%
1684
June1st to 15thNight
38%10%16%22%10%
1620
16th to endNight
34%11%19%17%14%3
1620
July1st to 15thNight
37%12%26%14%6%1
1530
16th to endNight
35%14%23%18%7%1
1595
August1st to 15thNight
36%12%23%19%7%1
1666
16th to endNight
42%12%18%15%10%1
1918
September1st to 15thNight
39%9%14%16%15%4
1980
16th to endNight
42%7%12%14%17%4
1837
October1st to 15thNight
31%5%7%21%19%14%
1818
16th to endNight
28%36%15%28%17%
2112
November1st to 15thNight
28%46%14%29%16%
2215
16th to endNight
33%36%16%23%16%
2340
December1st to 15thNight
37%5%8%18%22%8%
2340
16th to endNight
45%46%18%16%8%
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
14%13%34%23%7%6%
90
16th to endDay
13%14%50%11%10%
96
February1st to 15thDay
12%16%37%23%10%
90
16th to endDay
17%8%37%35%1
81
March1st to 15thDay
13%6%29%33%15%1
204
16th to endDay
13%329%34%18%1
288
April1st to 15thDay
14%11%20%28%20%5%
270
16th to endDay
9%221%27%28%11%
270
May1st to 15thDay
10%7%19%23%23%15%
288
16th to endDay
9%111%20%31%26%
331
June1st to 15thDay
11%17%17%29%32%
315
16th to endDay
8%5%17%26%40%
315
July1st to 15thDay
6%315%31%42%
305
16th to endDay
8%115%32%41%
326
August1st to 15thDay
16%214%37%28%
313
16th to endDay
11%1418%32%31%
332
September1st to 15thDay
15%16%19%29%26%
315
16th to endDay
22%9%25%30%11%
259
October1st to 15thDay
17%213%27%29%9%
255
16th to endDay
9%5%18%28%29%9%
272
November1st to 15thDay
17%6%23%26%22%3
148
16th to endDay
8%7%25%31%21%5%
90
December1st to 15thDay
22%233%27%11%3
90
16th to endDay
31%11%19%23%11%2
96
January1st to 15thNight
17%9%33%28%9%
720
16th to endNight
19%8%33%31%7%
768
February1st to 15thNight
16%8%32%34%8%
704
16th to endNight
16%6%38%33%5%
631
March1st to 15thNight
12%8%34%35%8%
720
16th to endNight
13%6%28%32%17%
768
April1st to 15thNight
14%5%26%33%18%
677
16th to endNight
8%226%35%25%1
540
May1st to 15thNight
6%223%37%25%3
540
16th to endNight
7%12%36%35%5%
563
June1st to 15thNight
7%28%34%38%8%
540
16th to endNight
5%5%28%48%11%
540
July1st to 15thNight
7%425%41%19%
510
16th to endNight
8%322%52%12%
564
August1st to 15thNight
6%421%52%14%
539
16th to endNight
14%420%42%16%
581
September1st to 15thNight
12%16%26%43%9%
720
16th to endNight
15%110%34%35%2
665
October1st to 15thNight
15%117%32%29%4
660
16th to endNight
11%320%32%27%3
704
November1st to 15thNight
12%320%39%21%2
700
16th to endNight
14%5%29%30%18%1
720
December1st to 15thNight
15%429%32%16%1
720
16th to endNight
22%6%25%33%10%1
768
Page generated at 2017-09-18 08:38:25. Version ac04

Copyright 2017 A. Danko


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