Coarsegold
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Coarsegold clear sky chart from 2005-11-05 to 2017-04-26.

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
76%
14976
30%
45595
29%
14943
78%
14943
47%
23049

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
69%
716
21%
2488
24%
716
71%
716
33%
1372
January16th to endNight
65%
768
25%
2496
27%
768
66%
768
31%
1478
February1st to 15thNight
66%
697
25%
2175
27%
697
68%
697
33%
1269
February16th to endNight
64%
632
23%
1895
25%
632
66%
632
32%
1155
March1st to 15thNight
67%
720
19%
2121
21%
720
68%
720
36%
1235
March16th to endNight
68%
768
24%
2014
18%
768
71%
768
44%
1178
April1st to 15thNight
64%
719
25%
1799
15%
719
66%
719
42%
1085
April16th to endNight
70%
704
26%
1760
14%
704
73%
704
52%
968
May1st to 15thNight
74%
572
31%
1562
21%
572
76%
572
60%
758
May16th to endNight
75%
379
29%
1406
29%
379
79%
379
50%
585
June1st to 15thNight
82%
330
33%
1320
40%
330
86%
330
56%
482
June16th to endNight
92%
330
37%
1320
48%
330
94%
330
78%
391
July1st to 15thNight
93%
310
38%
1240
50%
310
93%
310
71%
389
July16th to endNight
90%
436
37%
1384
38%
406
91%
406
63%
550
August1st to 15thNight
91%
607
40%
1591
28%
604
92%
604
83%
675
August16th to endNight
94%
700
43%
1750
28%
700
94%
700
83%
779
September1st to 15thNight
93%
660
45%
1650
33%
660
94%
660
81%
741
September16th to endNight
89%
656
45%
1785
41%
656
91%
656
76%
767
October1st to 15thNight
82%
660
34%
1939
36%
660
83%
660
57%
912
October16th to endNight
83%
704
39%
2117
43%
704
85%
704
59%
971
November1st to 15thNight
80%
700
31%
2275
36%
700
82%
700
50%
1064
November16th to endNight
76%
720
29%
2340
32%
720
77%
720
41%
1213
December1st to 15thNight
68%
720
23%
2480
26%
720
70%
720
31%
1414
December16th to endNight
59%
768
23%
2688
24%
768
63%
768
26%
1618

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
8%312212335%65%
46061
Night
9%212212235%65%
45783
TransparencyDay
22%38%18%25%20%
45741
Night
22%310%20%24%18%
45603
SeeingDay
10%7%26%35%15%4
5290
Night
9%17%34%37%9%
14989

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
14%413213346%53%
1447
16th to endDay
19%414323346%46%
1728
February1st to 15thDay
16%5%13323446%49%
1679
16th to endDay
20%5%14323345%45%
1579
March1st to 15thDay
14%6%133245%49%43%
1836
16th to endDay
14%5%143235%46%48%
2208
April1st to 15thDay
14%5%24413335%52%
2149
16th to endDay
9%323313336%58%
2111
May1st to 15thDay
4312212235%70%
2056
16th to endDay
6%22213447%63%
2353
June1st to 15thDay
322212335%73%
2310
16th to endDay
1111111386%
2310
July1st to 15thDay
1111112483%
2310
16th to endDay
11111223280%
2371
August1st to 15thDay
1111288%
2028
16th to endDay
11111122384%
2100
September1st to 15thDay
11111112285%
1980
16th to endDay
211123381%
1843
October1st to 15thDay
5%22213345%67%
1689
16th to endDay
6%21222245%69%
1755
November1st to 15thDay
9%212422245%61%
1584
16th to endDay
10%313324346%57%
1620
December1st to 15thDay
17%5%13323335%50%
1479
16th to endDay
18%5%34412327%45%
1536
January1st to 15thNight
13%413222347%54%
2488
16th to endNight
16%5%12313345%50%
2496
February1st to 15thNight
14%413312448%50%
2171
16th to endNight
20%413312436%49%
1895
March1st to 15thNight
15%323223346%53%
2121
16th to endNight
13%312212337%57%
2014
April1st to 15thNight
12%41322235%6%56%
1799
16th to endNight
7%21221232468%
1760
May1st to 15thNight
4112212236%72%
1562
16th to endNight
5%2113235%71%
1405
June1st to 15thNight
312212225%75%
1320
16th to endNight
1111388%
1320
July1st to 15thNight
111121384%
1320
16th to endNight
22111212478%
1488
August1st to 15thNight
111112287%
1600
16th to endNight
111111286%
1750
September1st to 15thNight
11111287%
1650
16th to endNight
211112384%
1785
October1st to 15thNight
5%212112246%69%
1939
16th to endNight
6%11112235%72%
2117
November1st to 15thNight
8%22212136%67%
2275
16th to endNight
7%313313346%60%
2340
December1st to 15thNight
14%414224347%51%
2480
16th to endNight
20%414323236%47%
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
32%413%20%20%7%
1447
16th to endDay
39%5%12%14%15%11%
1728
February1st to 15thDay
36%5%11%23%18%4
1679
16th to endDay
42%5%10%25%14%1
1579
March1st to 15thDay
36%7%13%18%16%6%
1836
16th to endDay
34%7%15%22%16%3
2208
April1st to 15thDay
34%411%26%17%5%
2149
16th to endDay
27%5%10%26%24%5%
2111
May1st to 15thDay
17%39%23%34%10%
2056
16th to endDay
19%410%30%26%7%
2357
June1st to 15thDay
13%410%19%28%23%
2310
16th to endDay
7%1210%37%41%
2310
July1st to 15thDay
7%137%24%56%
2161
16th to endDay
10%3410%21%49%
2212
August1st to 15thDay
4128%29%52%
2012
16th to endDay
7%128%37%43%
2100
September1st to 15thDay
7%139%32%44%
1980
16th to endDay
8%1321%38%25%
1843
October1st to 15thDay
19%37%21%28%19%
1689
16th to endDay
18%28%25%28%17%
1755
November1st to 15thDay
26%313%21%25%9%
1584
16th to endDay
29%312%21%26%6%
1620
December1st to 15thDay
38%5%10%20%20%4
1479
16th to endDay
40%6%13%19%15%5%
1536
January1st to 15thNight
31%411%23%21%7%
2488
16th to endNight
36%411%15%19%12%
2496
February1st to 15thNight
32%5%10%27%16%6%
2182
16th to endNight
36%414%26%15%2
1895
March1st to 15thNight
31%5%17%19%21%5%
2121
16th to endNight
27%5%16%26%19%4
2014
April1st to 15thNight
28%5%14%28%18%4
1799
16th to endNight
21%415%26%26%6%
1760
May1st to 15thNight
14%39%25%33%13%
1563
16th to endNight
15%49%30%30%9%
1406
June1st to 15thNight
13%211%20%28%24%
1320
16th to endNight
5%1310%33%46%
1320
July1st to 15thNight
6%216%26%56%
1240
16th to endNight
11%237%22%52%
1384
August1st to 15thNight
6%211%27%51%
1591
16th to endNight
6%127%35%46%
1750
September1st to 15thNight
6%128%32%48%
1650
16th to endNight
8%1217%42%26%
1785
October1st to 15thNight
17%38%24%28%19%
1939
16th to endNight
15%36%25%29%19%
2117
November1st to 15thNight
20%313%24%26%11%
2275
16th to endNight
24%5%11%23%25%9%
2340
December1st to 15thNight
33%5%13%22%19%6%
2480
16th to endNight
39%413%19%15%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
40%222%16%12%6%
75
16th to endDay
23%419%29%16%5%
256
February1st to 15thDay
22%424%23%18%7%
254
16th to endDay
23%10%25%25%14%1
238
March1st to 15thDay
14%13%24%25%17%4
270
16th to endDay
18%13%28%26%11%2
288
April1st to 15thDay
18%16%31%24%6%1
269
16th to endDay
13%15%33%25%9%1
254
May1st to 15thDay
8%13%36%32%6%3
228
16th to endDay
8%15%25%36%9%4
266
June1st to 15thDay
312%32%36%12%1
255
16th to endDay
1429%41%15%7%
255
July1st to 15thDay
120%51%19%6%
245
16th to endDay
19%54%16%7%
271
August1st to 15thDay
1228%49%9%8%
255
16th to endDay
1122%51%16%7%
268
September1st to 15thDay
2124%49%17%5%
255
16th to endDay
46%23%43%20%2
255
October1st to 15thDay
48%30%38%16%2
255
16th to endDay
8%425%35%23%2
267
November1st to 15thDay
8%28%13%46%20%
90
16th to endDay
10%8%24%32%21%3
90
December1st to 15thDay
14%231%29%20%
67
16th to endDay
25%115%32%15%9%
64
January1st to 15thNight
14%18%35%27%11%
720
16th to endNight
18%27%35%26%9%
768
February1st to 15thNight
17%18%35%27%9%
704
16th to endNight
21%27%34%27%6%
632
March1st to 15thNight
14%29%36%29%7%
720
16th to endNight
13%211%35%32%4
768
April1st to 15thNight
11%414%37%27%3
719
16th to endNight
7%215%36%30%7%
704
May1st to 15thNight
4114%42%31%5%
573
16th to endNight
6%212%34%40%3
380
June1st to 15thNight
47%40%43%3
330
16th to endNight
1338%52%3
330
July1st to 15thNight
127%65%4
310
16th to endNight
1218%61%15%
436
August1st to 15thNight
427%57%10%
607
16th to endNight
1123%63%10%
700
September1st to 15thNight
1326%53%15%
660
16th to endNight
2429%50%13%
656
October1st to 15thNight
6%5%36%39%10%
660
16th to endNight
7%5%31%37%17%
704
November1st to 15thNight
9%15%30%38%14%
700
16th to endNight
8%7%40%30%12%
720
December1st to 15thNight
15%16%42%26%7%
720
16th to endNight
22%110%39%22%5%
768
Page generated at 2017-04-27 14:48:46. Version ac04

Copyright 2017 A. Danko


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