Dome Creek
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Dome Creek clear sky chart from 2005-11-06 to 2024-02-05.

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%
23440
7%
81146
5%
23323
38%
23323
11%
63246

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 10thNight
24%
1020
5%
5026
4%
1002
25%
1002
5%
4083
January11th to 20thNight
25%
839
14%
4630
6%
820
28%
820
5%
3354
January21st to endNight
26%
905
6%
5115
6%
880
31%
880
4%
4343
February1st to 10thNight
28%
738
8%
2582
8%
738
30%
738
9%
2082
February11th to 20thNight
29%
701
6%
2285
5%
700
32%
700
9%
1867
February21st to endNight
35%
592
13%
1898
9%
592
41%
592
13%
1444
March1st to 10thNight
32%
720
11%
2160
8%
720
35%
720
14%
1684
March11th to 20thNight
35%
720
10%
2034
6%
720
37%
720
12%
1640
March21st to endNight
38%
792
8%
2044
4%
792
40%
792
13%
1665
April1st to 10thNight
41%
720
7%
1800
4%
720
41%
720
14%
1460
April11th to 20thNight
44%
575
9%
1643
6%
575
46%
575
17%
1252
April21st to endNight
42%
360
8%
1440
11%
360
44%
360
11%
1057
May1st to 10thNight
45%
360
5%
1440
6%
360
45%
360
10%
1090
May11th to 20thNight
52%
354
4%
1374
2%
354
52%
354
17%
910
May21st to endNight
49%
388
0%
1164
0%
388
49%
388
19%
842
June1st to 10thNight
46%
360
0%
1080
0%
360
46%
360
17%
792
June11th to 20thNight
42%
360
0%
1080
0%
360
42%
360
12%
866
June21st to endNight
50%
360
0%
1080
0%
360
50%
360
18%
793
July1st to 10thNight
56%
350
0%
1050
0%
350
56%
350
22%
728
July11th to 20thNight
55%
348
0%
1116
0%
348
55%
348
16%
812
July21st to endNight
62%
394
4%
1315
2%
372
65%
372
22%
836
August1st to 10thNight
63%
358
6%
1424
9%
356
63%
356
21%
872
August11th to 20thNight
66%
356
13%
1424
20%
356
68%
356
22%
873
August21st to endNight
48%
615
9%
1803
9%
615
49%
615
15%
1393
September1st to 10thNight
48%
720
9%
1800
5%
720
50%
720
19%
1395
September11th to 20thNight
55%
720
16%
1800
10%
720
56%
720
26%
1280
September21st to endNight
37%
720
11%
2039
7%
720
39%
720
15%
1574
October1st to 10thNight
41%
720
6%
2160
5%
720
42%
720
15%
1635
October11th to 20thNight
35%
720
9%
2219
6%
720
39%
720
12%
1755
October21st to endNight
30%
792
6%
2645
5%
792
32%
792
10%
2115
November1st to 10thNight
23%
740
6%
2590
5%
740
26%
740
6%
2171
November11th to 20thNight
22%
834
5%
2734
3%
834
24%
834
6%
2351
November21st to endNight
23%
966
5%
2884
2%
966
25%
966
8%
2489
December1st to 10thNight
31%
1040
7%
3040
5%
1040
33%
1040
10%
2530
December11th to 20thNight
25%
1040
5%
3747
4%
1039
26%
1039
7%
3239
December21st to endNight
24%
1143
4%
5481
4%
1114
27%
1114
6%
3974

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
12%12%5%9%8%46%5%6%7%25%
77325
Night
12%15%6%9%7%46%5%5%7%23%
81474
TransparencyDay
57%11%14%13%5%
77015
Night
58%11%13%13%5%1
81364
SeeingDay
20%10%22%27%16%4
15221
Night
24%9%20%31%16%1
23477

By Month

Percentage Cloud Cover NW (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 10thDay
10%18%7%14%11%6%6%5%46%13%
1935
11th to 20thDay
10%16%7%10%5%2445%6%30%
2199
21st to endDay
11%15%5%10%9%6%7%6%7%7%15%
2520
February1st to 10thDay
10%21%8%11%7%34435%22%
1472
11th to 20thDay
9%20%9%13%8%46%445%19%
1561
21st to endDay
417%7%12%9%5%5%5%46%26%
1357
March1st to 10thDay
5%16%7%10%9%5%6%5%46%25%
1800
11th to 20thDay
5%16%7%9%9%6%8%6%6%6%23%
1926
21st to endDay
8%18%7%9%8%36%5%6%6%23%
2312
April1st to 10thDay
6%14%6%12%9%5%8%7%6%8%19%
2160
11th to 20thDay
10%13%410%9%5%7%6%6%7%24%
2266
21st to endDay
11%13%5%10%8%46%5%6%6%25%
2520
May1st to 10thDay
12%16%5%9%8%36%5%6%7%24%
2520
11th to 20thDay
11%9%47%7%5%7%6%6%8%31%
2518
21st to endDay
14%8%47%7%48%6%7%8%27%
3111
June1st to 10thDay
14%9%48%7%5%7%7%6%7%25%
2880
11th to 20thDay
20%10%48%8%5%7%7%6%7%17%
2880
21st to endDay
15%8%48%8%5%6%5%6%7%28%
2880
July1st to 10thDay
17%6%37%7%46%6%6%7%32%
2880
11th to 20thDay
14%7%48%7%5%6%6%6%8%30%
2806
21st to endDay
13%5%46%7%35%5%5%8%39%
2925
August1st to 10thDay
10%6%26%7%47%6%7%9%37%
2507
11th to 20thDay
12%5%36%7%45%5%6%8%39%
2475
21st to endDay
17%7%48%8%5%6%6%5%9%25%
2550
September1st to 10thDay
17%8%37%8%5%6%6%5%7%30%
2160
11th to 20thDay
15%9%36%6%45%5%6%6%34%
2160
21st to endDay
20%12%38%6%45%45%7%24%
1918
October1st to 10thDay
15%13%48%6%45%5%5%7%29%
1800
11th to 20thDay
18%15%5%8%7%46%5%46%23%
1740
21st to endDay
18%18%5%8%6%35%46%5%23%
1710
November1st to 10thDay
18%19%6%11%7%4435%6%17%
1488
11th to 20thDay
10%21%9%12%8%45%5%5%5%17%
1425
21st to endDay
12%22%7%11%9%35%46%5%16%
1292
December1st to 10thDay
11%17%6%11%10%5%5%5%5%5%20%
1140
11th to 20thDay
11%21%7%12%9%5%7%6%35%14%
1442
21st to endDay
8%16%6%11%8%5%6%6%8%8%19%
2090
January1st to 10thNight
8%21%8%12%9%5%7%6%6%8%9%
5042
11th to 20thNight
10%16%7%9%7%5%7%6%5%5%24%
4699
21st to endNight
16%22%6%11%7%45%5%45%14%
5122
February1st to 10thNight
11%22%7%12%8%345%45%20%
2582
11th to 20thNight
11%19%8%11%7%445%46%20%
2283
21st to endNight
6%18%6%10%9%46%45%6%27%
1898
March1st to 10thNight
8%15%6%10%8%45%6%5%7%26%
2160
11th to 20thNight
5%15%6%11%9%6%7%6%5%7%22%
2033
21st to endNight
8%15%7%10%8%46%6%6%7%23%
2044
April1st to 10thNight
8%14%6%10%8%47%7%7%6%24%
1800
11th to 20thNight
10%11%5%7%7%5%7%7%8%8%27%
1643
21st to endNight
14%14%47%7%46%5%6%7%27%
1440
May1st to 10thNight
14%12%48%7%37%5%6%8%25%
1440
11th to 20thNight
12%8%36%5%36%7%7%9%34%
1374
21st to endNight
12%9%36%5%46%6%7%9%32%
1164
June1st to 10thNight
12%9%48%7%36%6%6%8%31%
1080
11th to 20thNight
20%10%49%6%47%46%8%23%
1080
21st to endNight
15%7%35%7%45%7%6%8%32%
1080
July1st to 10thNight
14%5%36%5%47%5%7%8%37%
1080
11th to 20thNight
13%7%46%7%47%5%6%9%33%
1152
21st to endNight
13%5%35%5%35%5%6%8%41%
1392
August1st to 10thNight
10%5%36%6%25%5%6%8%43%
1432
11th to 20thNight
10%5%25%5%45%6%6%8%44%
1424
21st to endNight
17%8%38%7%5%6%6%6%7%28%
1803
September1st to 10thNight
17%9%47%6%345%6%7%31%
1800
11th to 20thNight
15%9%36%5%34447%41%
1800
21st to endNight
21%10%37%6%4445%6%30%
2039
October1st to 10thNight
17%10%46%8%36%5%6%7%28%
2160
11th to 20thNight
18%12%48%6%46%6%5%6%24%
2219
21st to endNight
17%18%48%6%45%5%5%6%22%
2645
November1st to 10thNight
18%20%5%10%7%5%5%446%16%
2590
11th to 20thNight
13%21%8%12%8%45%5%4416%
2734
21st to endNight
12%23%8%10%8%5%6%445%15%
2884
December1st to 10thNight
11%18%6%13%8%5%5%6%5%5%18%
3040
11th to 20thNight
12%25%8%10%7%36%445%15%
3750
21st to endNight
7%16%8%11%8%46%5%5%7%23%
5566

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 10thDay
68%10%13%6%3
1935
11th to 20thDay
54%9%10%9%12%5%
2220
21st to endDay
58%17%15%7%3
2520
February1st to 10thDay
65%7%9%9%10%
1472
11th to 20thDay
68%8%11%8%4
1570
21st to endDay
62%5%12%11%7%2
1357
March1st to 10thDay
58%9%12%11%9%1
1800
11th to 20thDay
60%11%11%13%5%
1926
21st to endDay
63%10%14%11%3
2312
April1st to 10thDay
63%11%13%10%3
2160
11th to 20thDay
58%8%14%16%3
2266
21st to endDay
58%10%14%14%4
2520
May1st to 10thDay
60%8%14%14%3
2520
11th to 20thDay
50%11%15%16%7%
2521
21st to endDay
54%10%16%16%41
3112
June1st to 10thDay
56%11%13%14%6%
2880
11th to 20thDay
64%11%12%11%1
2880
21st to endDay
56%9%16%14%5%
2880
July1st to 10thDay
50%11%15%18%5%
2801
11th to 20thDay
51%13%16%17%3
2719
21st to endDay
41%12%20%21%6%
2762
August1st to 10thDay
42%13%20%18%5%1
2490
11th to 20thDay
42%12%20%20%5%1
2475
21st to endDay
57%10%15%13%4
2550
September1st to 10thDay
53%11%16%14%5%1
2160
11th to 20thDay
50%9%17%17%6%
2160
21st to endDay
59%10%13%12%5%1
1918
October1st to 10thDay
55%9%19%13%4
1800
11th to 20thDay
61%10%14%13%2
1740
21st to endDay
62%9%14%14%2
1710
November1st to 10thDay
68%10%8%12%31
1488
11th to 20thDay
67%11%11%8%31
1425
21st to endDay
68%10%9%6%5%1
1292
December1st to 10thDay
62%12%11%12%3
1140
11th to 20thDay
71%11%7%7%4
1444
21st to endDay
53%13%20%10%4
2090
January1st to 10thNight
63%13%12%8%3
5042
11th to 20thNight
59%7%9%8%11%6%
4740
21st to endNight
66%14%8%8%3
5122
February1st to 10thNight
66%7%10%10%7%
2582
11th to 20thNight
65%8%12%11%3
2285
21st to endNight
58%8%12%14%7%2
1898
March1st to 10thNight
56%10%12%14%7%1
2160
11th to 20thNight
59%11%12%13%5%1
2034
21st to endNight
59%11%14%13%3
2044
April1st to 10thNight
58%11%11%14%6%
1800
11th to 20thNight
53%10%14%18%5%
1643
21st to endNight
56%9%10%20%5%
1440
May1st to 10thNight
58%10%14%15%4
1440
11th to 20thNight
45%9%18%20%7%
1374
21st to endNight
48%11%18%18%41
1164
June1st to 10thNight
48%12%15%16%8%
1080
11th to 20thNight
58%13%12%16%2
1080
21st to endNight
48%12%19%18%3
1080
July1st to 10thNight
43%11%18%21%7%
1050
11th to 20thNight
49%12%16%19%4
1116
21st to endNight
38%12%22%24%5%
1315
August1st to 10thNight
38%11%22%23%7%
1424
11th to 20thNight
35%12%20%27%5%1
1424
21st to endNight
53%12%15%15%41
1803
September1st to 10thNight
52%11%14%19%42
1800
11th to 20thNight
44%8%15%25%7%
1800
21st to endNight
54%11%13%15%7%
2039
October1st to 10thNight
53%11%19%14%4
2160
11th to 20thNight
58%11%14%14%3
2219
21st to endNight
61%10%14%11%4
2645
November1st to 10thNight
68%9%8%10%4
2590
11th to 20thNight
68%11%8%7%4
2734
21st to endNight
70%9%8%7%5%1
2884
December1st to 10thNight
63%11%11%10%4
3040
11th to 20thNight
69%11%9%8%3
3747
21st to endNight
54%13%17%14%2
5566

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 10thDay
18%11%17%33%16%5%
180
11th to 20thDay
23%8%26%21%19%3
180
21st to endDay
25%9%21%28%13%4
198
February1st to 10thDay
27%15%20%24%11%1
168
11th to 20thDay
22%16%24%25%11%2
321
21st to endDay
15%16%32%22%11%4
292
March1st to 10thDay
15%14%26%26%16%2
420
11th to 20thDay
16%17%26%25%12%4
420
21st to endDay
23%16%23%22%11%5%
462
April1st to 10thDay
16%15%30%25%11%3
420
11th to 20thDay
16%17%23%26%11%6%
412
21st to endDay
17%14%25%25%13%5%
420
May1st to 10thDay
18%9%26%26%18%3
423
11th to 20thDay
15%421%32%22%6%
488
21st to endDay
17%7%20%33%20%3
874
June1st to 10thDay
19%9%25%30%14%1
810
11th to 20thDay
24%9%22%28%15%3
810
21st to endDay
20%8%21%25%21%5%
810
July1st to 10thDay
18%8%18%32%21%3
796
11th to 20thDay
18%8%18%29%22%4
718
21st to endDay
13%8%21%32%20%7%
671
August1st to 10thDay
11%8%20%30%25%7%
447
11th to 20thDay
16%9%26%27%17%5%
437
21st to endDay
18%9%24%26%14%8%
495
September1st to 10thDay
20%10%20%27%17%6%
450
11th to 20thDay
23%7%18%30%16%7%
450
21st to endDay
29%12%23%20%13%3
450
October1st to 10thDay
26%10%17%22%19%5%
450
11th to 20thDay
30%11%21%21%13%4
390
21st to endDay
30%10%18%28%10%4
261
November1st to 10thDay
32%19%16%20%9%3
180
11th to 20thDay
23%11%20%28%12%6%
180
21st to endDay
31%15%18%22%8%6%
180
December1st to 10thDay
18%8%18%31%21%4
180
11th to 20thDay
26%8%17%26%21%3
180
21st to endDay
22%9%19%30%14%6%
198
January1st to 10thNight
27%11%24%26%10%2
1036
11th to 20thNight
28%13%21%28%9%1
850
21st to endNight
30%10%21%27%10%1
910
February1st to 10thNight
28%12%20%27%13%1
738
11th to 20thNight
25%10%21%31%12%1
704
21st to endNight
18%7%27%31%16%2
592
March1st to 10thNight
20%9%27%29%14%1
720
11th to 20thNight
16%11%27%33%11%1
720
21st to endNight
18%12%20%29%19%3
792
April1st to 10thNight
20%8%16%36%18%2
720
11th to 20thNight
16%10%23%33%19%1
575
21st to endNight
22%7%20%33%18%1
360
May1st to 10thNight
20%7%16%37%19%1
360
11th to 20thNight
17%319%38%21%2
354
21st to endNight
15%5%20%37%22%2
389
June1st to 10thNight
17%7%19%39%18%1
360
11th to 20thNight
27%5%16%34%16%2
360
21st to endNight
20%5%16%34%23%3
360
July1st to 10thNight
17%5%13%39%25%1
350
11th to 20thNight
18%6%12%31%31%2
348
21st to endNight
14%7%9%37%29%4
394
August1st to 10thNight
12%6%8%31%39%4
358
11th to 20thNight
12%49%42%31%3
356
21st to endNight
24%6%9%35%24%1
615
September1st to 10thNight
26%6%11%33%23%1
720
11th to 20thNight
21%410%34%28%3
720
21st to endNight
29%10%16%29%14%1
720
October1st to 10thNight
26%6%18%33%17%1
720
11th to 20thNight
28%8%19%29%15%1
720
21st to endNight
33%9%20%28%9%1
792
November1st to 10thNight
35%12%21%22%10%
740
11th to 20thNight
29%16%23%24%8%1
834
21st to endNight
32%13%21%25%8%1
966
December1st to 10thNight
23%10%20%34%11%1
1040
11th to 20thNight
27%12%24%26%10%1
1040
21st to endNight
21%11%27%28%11%1
1144
Page generated at 2024-02-02 02:20:28. Version ac07

Copyright 2024 Attilla Danko


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