Getchell Mountain
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Getchell Mountain clear sky chart from 2005-11-06 to 2024-01-14.

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
23%
23102
15%
74832
6%
23049
34%
23049
16%
51543

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
16%
801
14%
2737
3%
798
29%
798
11%
1927
January11th to 20thNight
15%
735
13%
2569
2%
735
27%
735
9%
1885
January21st to endNight
16%
792
18%
2727
4%
792
33%
792
15%
1809
February1st to 10thNight
14%
720
14%
2340
4%
720
26%
720
12%
1674
February11th to 20thNight
11%
703
13%
2228
2%
700
25%
700
11%
1605
February21st to endNight
16%
592
19%
1776
5%
592
34%
592
15%
1243
March1st to 10thNight
16%
720
19%
2124
6%
720
30%
720
16%
1515
March11th to 20thNight
18%
720
16%
1980
5%
720
29%
720
15%
1441
March21st to endNight
21%
792
18%
2178
5%
792
31%
792
18%
1558
April1st to 10thNight
15%
702
15%
1833
3%
702
24%
702
16%
1351
April11th to 20thNight
17%
534
18%
1598
5%
534
28%
534
16%
1103
April21st to endNight
18%
540
13%
1620
4%
540
26%
540
13%
1192
May1st to 10thNight
23%
540
15%
1620
6%
540
33%
540
16%
1152
May11th to 20thNight
18%
532
14%
1593
5%
532
27%
532
14%
1169
May21st to endNight
26%
437
12%
1405
7%
436
35%
436
16%
987
June1st to 10thNight
24%
360
11%
1260
7%
360
32%
360
14%
908
June11th to 20thNight
28%
360
13%
1260
10%
360
36%
360
19%
837
June21st to endNight
30%
360
9%
1260
6%
360
36%
360
15%
902
July1st to 10thNight
33%
350
12%
1225
7%
350
44%
350
21%
809
July11th to 20thNight
37%
348
12%
1359
13%
348
44%
348
18%
878
July21st to endNight
38%
425
12%
1516
10%
402
46%
402
18%
992
August1st to 10thNight
37%
538
11%
1600
7%
534
41%
534
24%
1074
August11th to 20thNight
40%
532
14%
1596
9%
532
44%
532
20%
1094
August21st to endNight
41%
594
22%
1782
11%
594
47%
594
28%
1092
September1st to 10thNight
36%
666
17%
1856
7%
666
44%
666
31%
1155
September11th to 20thNight
39%
720
20%
1980
12%
720
46%
720
31%
1234
September21st to endNight
31%
720
23%
1980
10%
720
43%
720
27%
1282
October1st to 10thNight
34%
720
22%
2064
12%
720
43%
720
25%
1342
October11th to 20thNight
27%
720
19%
2160
6%
720
39%
720
20%
1452
October21st to endNight
18%
792
14%
2560
4%
792
30%
792
14%
1823
November1st to 10thNight
21%
740
19%
2407
7%
740
35%
740
17%
1601
November11th to 20thNight
22%
823
21%
2603
8%
823
39%
823
16%
1743
November21st to endNight
18%
850
15%
2660
3%
850
31%
850
14%
1845
December1st to 10thNight
16%
850
14%
2759
4%
850
27%
850
12%
2016
December11th to 20thNight
14%
850
14%
3456
3%
849
26%
849
9%
2412
December21st to endNight
11%
924
10%
5161
2%
906
25%
906
6%
3441

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
19%8%36%6%35%45%7%34%
74612
Night
19%9%36%5%3445%6%35%
75149
TransparencyDay
48%6%11%20%12%2
74313
Night
49%6%11%20%12%1
74983
SeeingDay
27%16%31%18%6%1
14828
Night
25%15%32%22%6%
23113

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 10thDay
15%12%5%8%6%445%46%31%
1426
11th to 20thDay
20%14%36%6%25%346%31%
1464
21st to endDay
14%9%47%6%34447%37%
1627
February1st to 10thDay
16%11%48%6%45%5%5%6%29%
1620
11th to 20thDay
15%12%5%8%6%45%45%6%30%
1618
21st to endDay
12%11%5%7%7%35%5%47%33%
1480
March1st to 10thDay
18%12%47%5%36%35%6%31%
1832
11th to 20thDay
17%8%5%7%7%3445%7%34%
1980
21st to endDay
18%11%47%6%3445%6%33%
2178
April1st to 10thDay
21%12%48%5%3445%6%27%
2123
11th to 20thDay
20%10%36%6%3435%5%34%
2312
21st to endDay
24%12%46%5%33445%31%
2340
May1st to 10thDay
23%9%36%6%34446%33%
2340
11th to 20thDay
22%8%35%5%4445%6%34%
2301
21st to endDay
18%7%36%6%35%5%5%8%34%
2885
June1st to 10thDay
25%8%47%5%35%45%7%28%
2700
11th to 20thDay
21%6%345%245%6%7%36%
2700
21st to endDay
25%8%37%5%35%5%5%6%27%
2700
July1st to 10thDay
16%6%26%5%46%6%7%8%35%
2700
11th to 20thDay
16%6%26%6%45%5%7%8%35%
2552
21st to endDay
15%6%36%6%45%5%6%9%33%
2695
August1st to 10thDay
16%6%25%7%35%5%7%8%35%
2327
11th to 20thDay
15%7%26%6%36%6%6%8%34%
2304
21st to endDay
15%5%26%6%35%447%43%
2574
September1st to 10thDay
11%5%35%5%3445%8%46%
2100
11th to 20thDay
16%6%34334435%49%
1980
21st to endDay
18%7%24423447%45%
1980
October1st to 10thDay
17%7%36%6%3335%7%41%
1895
11th to 20thDay
21%7%25%6%4435%6%37%
1800
21st to endDay
22%10%47%5%44346%32%
1794
November1st to 10thDay
21%7%26%4345%46%38%
1671
11th to 20thDay
20%7%25%4345%48%37%
1577
21st to endDay
21%9%35%6%2445%6%33%
1520
December1st to 10thDay
23%11%46%6%35%5%45%28%
1418
11th to 20thDay
22%11%46%6%245%45%30%
1668
21st to endDay
23%11%37%5%44445%30%
2431
January1st to 10thNight
16%11%5%8%7%4445%6%31%
2737
11th to 20thNight
17%12%48%7%45%5%45%29%
2569
21st to endNight
11%8%47%7%47%6%6%6%34%
2727
February1st to 10thNight
16%10%37%7%47%5%6%7%28%
2340
11th to 20thNight
14%12%48%8%45%5%5%7%30%
2225
21st to endNight
14%11%5%8%5%35%446%35%
1776
March1st to 10thNight
15%13%47%6%34446%34%
2115
11th to 20thNight
18%10%46%5%45%45%6%33%
1979
21st to endNight
18%11%47%5%3445%6%34%
2178
April1st to 10thNight
22%11%47%5%23446%32%
1833
11th to 20thNight
21%8%35%5%3445%7%34%
1598
21st to endNight
26%9%35%5%35%45%6%29%
1620
May1st to 10thNight
23%8%37%5%3446%6%33%
1620
11th to 20thNight
21%9%36%6%45%5%5%5%30%
1592
21st to endNight
18%9%36%6%25%5%5%7%35%
1404
June1st to 10thNight
24%8%36%6%35%5%5%7%27%
1260
11th to 20thNight
18%8%37%5%3345%8%36%
1260
21st to endNight
26%6%36%7%3435%7%31%
1260
July1st to 10thNight
14%7%36%4347%6%9%37%
1260
11th to 20thNight
17%7%35%435%5%8%8%35%
1405
21st to endNight
18%6%26%5%35%5%6%8%35%
1605
August1st to 10thNight
16%5%26%5%36%5%5%7%39%
1612
11th to 20thNight
15%8%35%5%45%6%5%8%36%
1596
21st to endNight
13%5%26%42445%7%49%
1782
September1st to 10thNight
14%5%244245%5%7%48%
1856
11th to 20thNight
16%6%24323446%49%
1980
21st to endNight
18%6%2442445%7%46%
1980
October1st to 10thNight
19%6%25%42445%6%42%
2064
11th to 20thNight
18%6%36%6%3445%6%38%
2160
21st to endNight
24%9%36%5%3435%5%33%
2560
November1st to 10thNight
19%7%36%5%335%47%37%
2407
11th to 20thNight
19%8%35%5%35%5%5%5%37%
2603
21st to endNight
19%9%36%5%345%5%7%34%
2660
December1st to 10thNight
24%10%46%5%34446%30%
2759
11th to 20thNight
25%8%35%5%34446%33%
3531
21st to endNight
23%11%46%5%23345%33%
5236

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
53%5%13%17%12%1
1427
11th to 20thDay
55%6%10%18%9%2
1464
21st to endDay
46%412%21%16%1
1627
February1st to 10thDay
54%6%11%17%10%2
1620
11th to 20thDay
54%6%10%18%12%1
1626
21st to endDay
50%6%10%20%11%4
1480
March1st to 10thDay
53%410%17%13%2
1836
11th to 20thDay
48%6%11%16%17%3
1980
21st to endDay
52%5%10%19%11%4
2178
April1st to 10thDay
57%5%9%14%12%3
2123
11th to 20thDay
49%5%10%20%15%1
2312
21st to endDay
54%48%16%13%4
2340
May1st to 10thDay
53%5%8%19%12%3
2340
11th to 20thDay
49%6%8%22%12%2
2305
21st to endDay
47%8%13%20%11%1
2885
June1st to 10thDay
54%6%12%18%10%1
2700
11th to 20thDay
46%5%11%20%16%2
2700
21st to endDay
54%8%11%16%9%1
2700
July1st to 10thDay
43%8%14%22%12%1
2625
11th to 20thDay
43%8%13%22%11%1
2475
21st to endDay
45%8%13%22%11%1
2544
August1st to 10thDay
44%9%14%24%8%
2314
11th to 20thDay
45%10%12%22%10%
2304
21st to endDay
40%7%12%25%15%1
2574
September1st to 10thDay
34%7%12%29%17%1
2100
11th to 20thDay
37%49%28%19%3
1980
21st to endDay
40%5%9%28%18%1
1980
October1st to 10thDay
44%5%11%26%14%
1895
11th to 20thDay
46%6%13%25%9%1
1800
21st to endDay
54%5%10%19%12%
1794
November1st to 10thDay
46%6%13%19%14%1
1671
11th to 20thDay
44%6%13%21%14%2
1577
21st to endDay
50%6%15%21%7%
1520
December1st to 10thDay
57%7%10%17%8%1
1418
11th to 20thDay
56%5%10%18%10%1
1668
21st to endDay
55%6%10%17%9%3
2431
January1st to 10thNight
52%6%11%19%10%1
2737
11th to 20thNight
56%7%11%17%8%1
2569
21st to endNight
45%7%11%23%12%1
2727
February1st to 10thNight
52%6%12%17%10%2
2340
11th to 20thNight
53%6%10%17%13%2
2228
21st to endNight
51%38%20%15%3
1776
March1st to 10thNight
51%5%8%20%14%2
2124
11th to 20thNight
52%5%10%17%14%2
1980
21st to endNight
49%5%9%20%14%2
2178
April1st to 10thNight
53%5%9%14%15%4
1833
11th to 20thNight
48%6%9%19%15%2
1598
21st to endNight
56%5%10%14%13%3
1620
May1st to 10thNight
51%6%9%18%15%2
1620
11th to 20thNight
53%7%9%19%11%1
1593
21st to endNight
49%8%11%19%12%1
1405
June1st to 10thNight
54%7%11%21%7%1
1260
11th to 20thNight
47%6%12%22%12%1
1260
21st to endNight
53%7%11%18%9%2
1260
July1st to 10thNight
42%9%16%21%12%
1225
11th to 20thNight
44%8%13%24%11%
1359
21st to endNight
45%8%16%19%11%1
1516
August1st to 10thNight
43%8%16%25%8%
1600
11th to 20thNight
45%9%16%22%8%
1596
21st to endNight
35%8%13%27%17%1
1782
September1st to 10thNight
34%7%14%30%14%1
1856
11th to 20thNight
36%5%13%26%18%2
1980
21st to endNight
39%6%10%29%16%1
1980
October1st to 10thNight
42%5%11%26%15%1
2064
11th to 20thNight
43%7%13%24%11%1
2160
21st to endNight
52%6%11%19%11%1
2560
November1st to 10thNight
45%7%12%23%12%1
2407
11th to 20thNight
46%6%12%22%13%1
2603
21st to endNight
49%6%14%19%10%1
2660
December1st to 10thNight
56%5%11%19%9%
2759
11th to 20thNight
53%5%11%17%14%1
3532
21st to endNight
53%5%11%18%9%3
5236

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
38%16%31%14%2
180
11th to 20thDay
33%22%35%5%41
166
21st to endDay
25%22%34%16%3
219
February1st to 10thDay
26%18%36%18%1
340
11th to 20thDay
28%28%31%11%21
356
21st to endDay
25%22%35%14%3
346
March1st to 10thDay
28%25%32%13%2
420
11th to 20thDay
28%19%34%15%41
420
21st to endDay
32%19%30%14%42
462
April1st to 10thDay
39%20%25%12%32
420
11th to 20thDay
34%21%27%12%4
412
21st to endDay
36%17%31%12%41
420
May1st to 10thDay
34%17%30%15%3
423
11th to 20thDay
30%20%28%18%31
447
21st to endDay
25%19%32%18%5%1
680
June1st to 10thDay
31%13%30%18%6%1
630
11th to 20thDay
26%14%28%21%8%2
630
21st to endDay
29%10%30%23%7%1
630
July1st to 10thDay
20%10%34%25%9%1
620
11th to 20thDay
21%10%36%23%8%2
474
21st to endDay
16%7%39%30%6%1
488
August1st to 10thDay
17%9%37%27%9%2
446
11th to 20thDay
19%10%28%30%10%2
439
21st to endDay
20%14%27%28%10%2
495
September1st to 10thDay
15%13%35%25%9%3
450
11th to 20thDay
24%11%31%17%13%4
450
21st to endDay
20%16%35%17%9%4
450
October1st to 10thDay
23%13%29%21%10%4
408
11th to 20thDay
25%18%31%16%8%2
360
21st to endDay
31%19%29%16%41
396
November1st to 10thDay
29%17%30%16%6%2
365
11th to 20thDay
31%20%29%14%6%
370
21st to endDay
31%21%28%17%3
370
December1st to 10thDay
31%18%35%13%4
268
11th to 20thDay
37%23%31%8%1
180
21st to endDay
37%23%27%9%4
198
January1st to 10thNight
25%19%33%21%2
801
11th to 20thNight
27%19%33%18%4
735
21st to endNight
20%19%38%20%31
792
February1st to 10thNight
25%20%35%18%2
720
11th to 20thNight
25%23%35%14%21
703
21st to endNight
24%21%32%21%3
592
March1st to 10thNight
27%16%36%19%1
720
11th to 20thNight
25%19%33%18%4
720
21st to endNight
24%18%33%19%5%1
792
April1st to 10thNight
32%17%32%16%3
702
11th to 20thNight
27%18%34%16%5%
534
21st to endNight
35%14%30%16%5%
540
May1st to 10thNight
29%14%29%24%4
540
11th to 20thNight
26%16%35%19%4
532
21st to endNight
20%14%35%25%6%
437
June1st to 10thNight
30%8%34%23%5%
360
11th to 20thNight
22%8%35%27%9%
360
21st to endNight
29%6%30%30%5%
360
July1st to 10thNight
17%5%38%33%6%
350
11th to 20thNight
18%5%31%36%8%1
348
21st to endNight
18%333%36%8%
425
August1st to 10thNight
19%432%35%10%
538
11th to 20thNight
19%6%27%34%12%1
532
21st to endNight
15%8%29%34%12%1
594
September1st to 10thNight
17%7%35%28%12%
666
11th to 20thNight
20%9%28%29%12%2
720
21st to endNight
21%11%32%24%10%1
720
October1st to 10thNight
22%10%28%27%13%
720
11th to 20thNight
21%14%33%23%8%1
720
21st to endNight
31%16%31%19%3
792
November1st to 10thNight
26%17%31%21%6%1
740
11th to 20thNight
26%17%30%19%8%1
823
21st to endNight
28%19%31%18%31
850
December1st to 10thNight
31%16%31%17%4
850
11th to 20thNight
30%21%29%18%2
850
21st to endNight
31%20%31%14%4
935
Page generated at 2024-01-11 04:22:40. Version ac07

Copyright 2024 Attilla Danko


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