Fremont Peak
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fremont Peak clear sky chart from 2005-11-06 to 2024-01-15.

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
64%
23835
26%
74799
24%
23787
67%
23787
35%
43001

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
54%
756
19%
2543
19%
756
57%
756
24%
1610
January11th to 20thNight
62%
738
22%
2397
21%
738
66%
738
30%
1432
January21st to endNight
58%
792
25%
2574
26%
792
61%
792
27%
1603
February1st to 10thNight
59%
720
25%
2340
26%
720
63%
720
30%
1390
February11th to 20thNight
56%
700
25%
2135
23%
700
62%
700
31%
1282
February21st to endNight
56%
592
25%
1776
23%
592
60%
592
32%
1068
March1st to 10thNight
49%
720
17%
2051
14%
720
53%
720
24%
1393
March11th to 20thNight
52%
720
21%
1980
18%
720
56%
720
28%
1325
March21st to endNight
54%
792
18%
2120
14%
792
58%
792
32%
1376
April1st to 10thNight
57%
720
21%
1800
14%
720
59%
720
33%
1182
April11th to 20thNight
52%
711
25%
1779
14%
711
55%
711
38%
1107
April21st to endNight
60%
720
26%
1800
14%
720
62%
720
43%
1076
May1st to 10thNight
61%
720
23%
1800
14%
720
62%
720
39%
1117
May11th to 20thNight
62%
489
21%
1552
18%
489
64%
489
30%
899
May21st to endNight
59%
388
20%
1552
19%
388
63%
388
24%
890
June1st to 10thNight
66%
360
24%
1440
27%
360
69%
360
30%
739
June11th to 20thNight
71%
360
30%
1440
36%
360
75%
360
39%
653
June21st to endNight
78%
360
31%
1440
40%
360
79%
360
46%
606
July1st to 10thNight
76%
350
27%
1400
35%
350
76%
350
39%
630
July11th to 20thNight
79%
500
29%
1544
27%
500
79%
500
47%
749
July21st to endNight
73%
591
28%
1674
24%
558
74%
558
45%
840
August1st to 10thNight
66%
537
24%
1602
20%
534
66%
534
38%
870
August11th to 20thNight
81%
707
33%
1775
22%
707
81%
707
61%
919
August21st to endNight
77%
792
31%
1980
20%
792
77%
792
56%
1074
September1st to 10thNight
82%
720
39%
1800
29%
720
82%
720
63%
925
September11th to 20thNight
75%
720
37%
1800
30%
720
76%
720
52%
1005
September21st to endNight
80%
720
39%
2019
37%
720
83%
720
60%
969
October1st to 10thNight
76%
720
29%
2160
31%
720
79%
720
51%
1068
October11th to 20thNight
73%
720
34%
2160
37%
720
76%
720
44%
1141
October21st to endNight
73%
792
37%
2376
39%
792
76%
792
47%
1217
November1st to 10thNight
68%
740
31%
2271
33%
740
70%
740
41%
1223
November11th to 20thNight
67%
760
28%
2470
28%
760
70%
760
35%
1348
November21st to endNight
67%
760
29%
2527
30%
760
71%
760
39%
1324
December1st to 10thNight
61%
760
24%
2660
26%
760
64%
760
30%
1520
December11th to 20thNight
52%
759
18%
3236
22%
759
56%
759
17%
2247
December21st to endNight
48%
829
13%
4826
19%
817
55%
817
12%
3184

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
6%5%24423447%57%
74720
Night
8%7%35%43445%7%51%
75073
TransparencyDay
26%5%9%18%24%18%
74440
Night
31%6%9%17%21%16%
74875
SeeingDay
8%9%26%32%19%6%
14324
Night
9%413%33%32%9%
23852

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 10thDay
15%8%46%5%3345%8%40%
1618
11th to 20thDay
9%5%25%4345%5%7%51%
1657
21st to endDay
14%8%36%5%335%46%44%
1782
February1st to 10thDay
14%7%35%423447%48%
1620
11th to 20thDay
12%7%35%5%145%5%6%47%
1713
21st to endDay
12%8%26%5%3445%5%45%
1480
March1st to 10thDay
13%8%46%6%35%6%5%7%36%
1907
11th to 20thDay
14%6%36%5%346%7%10%37%
1980
21st to endDay
10%8%35%6%24447%46%
2236
April1st to 10thDay
10%6%46%5%335%5%7%46%
2160
11th to 20thDay
8%6%35%444347%52%
2129
21st to endDay
7%5%35%423447%55%
2160
May1st to 10thDay
45%3432445%8%58%
2160
11th to 20thDay
442442346%9%57%
2336
21st to endDay
5%8%35%425%449%51%
2723
June1st to 10thDay
35%3443345%8%59%
2520
11th to 20thDay
2413222337%71%
2520
21st to endDay
2313323236%72%
2520
July1st to 10thDay
1324323247%70%
2520
11th to 20thDay
1223323348%68%
2359
21st to endDay
1222323349%71%
2546
August1st to 10thDay
2425%423339%63%
2328
11th to 20thDay
31231335%7%72%
2126
21st to endDay
1323323448%68%
2376
September1st to 10thDay
2312212236%78%
2160
11th to 20thDay
2423323348%66%
2160
21st to endDay
3212212346%74%
1936
October1st to 10thDay
4313323436%68%
1800
11th to 20thDay
4413423336%67%
1800
21st to endDay
442332335%6%64%
1980
November1st to 10thDay
7%5%25%424447%56%
1807
11th to 20thDay
7%5%25%5%245%5%6%54%
1710
21st to endDay
10%42433345%7%57%
1649
December1st to 10thDay
10%7%26%5%25%46%6%47%
1520
11th to 20thDay
18%11%47%6%25%5%5%6%32%
1928
21st to endDay
12%9%46%7%35%5%6%7%37%
2794
January1st to 10thNight
13%7%36%5%3445%7%42%
2543
11th to 20thNight
10%6%35%5%345%5%8%48%
2397
21st to endNight
13%7%26%5%345%5%6%44%
2574
February1st to 10thNight
12%7%34434346%50%
2340
11th to 20thNight
10%7%35%4345%6%7%47%
2134
21st to endNight
11%7%35%433346%51%
1776
March1st to 10thNight
13%9%37%5%3445%7%40%
2051
11th to 20thNight
12%9%37%5%345%48%40%
1980
21st to endNight
11%8%345%2445%6%48%
2120
April1st to 10thNight
11%7%345%345%5%7%47%
1800
11th to 20thNight
9%8%35%423446%52%
1779
21st to endNight
6%7%3332445%9%54%
1800
May1st to 10thNight
48%36%5%345%5%7%51%
1800
11th to 20thNight
48%37%5%345%5%7%48%
1551
21st to endNight
5%11%5%6%5%34446%48%
1552
June1st to 10thNight
47%37%4345%5%7%53%
1440
11th to 20thNight
36%3442345%7%59%
1440
21st to endNight
16%26%434335%62%
1440
July1st to 10thNight
15%46%5%3435%8%55%
1440
11th to 20thNight
15%37%3345%5%8%57%
1596
21st to endNight
15%48%6%335%5%10%49%
1773
August1st to 10thNight
18%5%9%8%46%5%5%6%46%
1611
11th to 20thNight
1425%5%3435%8%60%
1775
21st to endNight
16%47%33445%7%57%
1980
September1st to 10thNight
2434322347%68%
1800
11th to 20thNight
36%36%423447%60%
1800
21st to endNight
25%12412336%71%
2019
October1st to 10thNight
5%5%23423346%64%
2160
11th to 20thNight
6%6%25%324347%59%
2160
21st to endNight
5%6%2422335%5%63%
2376
November1st to 10thNight
7%5%34423336%58%
2271
11th to 20thNight
8%6%3332345%10%53%
2470
21st to endNight
7%435%334446%57%
2527
December1st to 10thNight
11%6%345%2445%6%50%
2660
11th to 20thNight
16%10%47%6%35%5%5%7%33%
3276
21st to endNight
14%9%36%6%45%6%5%7%34%
4862

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
44%6%10%22%13%5%
1618
11th to 20thDay
33%5%12%18%18%14%
1657
21st to endDay
42%6%8%13%22%9%
1782
February1st to 10thDay
38%47%20%20%12%
1620
11th to 20thDay
36%6%9%18%23%8%
1723
21st to endDay
41%5%8%22%19%6%
1480
March1st to 10thDay
44%8%10%17%18%4
1907
11th to 20thDay
41%8%10%19%18%4
1980
21st to endDay
39%6%15%21%16%4
2236
April1st to 10thDay
37%7%10%23%18%5%
2160
11th to 20thDay
31%6%12%25%20%6%
2132
21st to endDay
27%7%11%28%21%6%
2160
May1st to 10thDay
24%6%11%26%29%5%
2160
11th to 20thDay
22%5%11%26%28%8%
2339
21st to endDay
29%7%11%25%23%4
2724
June1st to 10thDay
22%7%12%23%26%11%
2520
11th to 20thDay
14%39%20%34%20%
2520
21st to endDay
12%36%13%29%36%
2520
July1st to 10thDay
12%35%11%22%47%
2451
11th to 20thDay
13%47%10%22%44%
2288
21st to endDay
8%35%12%29%42%
2405
August1st to 10thDay
16%35%13%26%37%
2312
11th to 20thDay
9%26%13%30%40%
2126
21st to endDay
11%45%14%30%36%
2376
September1st to 10thDay
9%339%27%48%
2160
11th to 20thDay
15%36%19%36%20%
2160
21st to endDay
12%35%21%39%21%
1936
October1st to 10thDay
17%48%17%28%26%
1800
11th to 20thDay
19%5%8%21%23%25%
1800
21st to endDay
20%48%19%25%23%
1980
November1st to 10thDay
28%5%9%19%25%15%
1807
11th to 20thDay
29%5%11%20%25%10%
1710
21st to endDay
29%49%17%27%15%
1649
December1st to 10thDay
35%6%11%17%18%13%
1520
11th to 20thDay
52%6%9%13%14%6%
1928
21st to endDay
45%6%13%21%11%4
2794
January1st to 10thNight
41%7%10%21%17%5%
2543
11th to 20thNight
35%6%12%17%16%14%
2397
21st to endNight
40%5%12%13%19%11%
2574
February1st to 10thNight
37%47%17%21%13%
2340
11th to 20thNight
35%6%10%17%24%7%
2135
21st to endNight
36%5%9%27%18%6%
1776
March1st to 10thNight
44%7%13%16%15%6%
2051
11th to 20thNight
41%7%10%17%18%7%
1980
21st to endNight
37%7%12%22%16%6%
2120
April1st to 10thNight
37%6%13%22%16%6%
1800
11th to 20thNight
32%5%13%25%19%6%
1779
21st to endNight
27%6%12%28%22%5%
1800
May1st to 10thNight
30%6%9%21%24%9%
1800
11th to 20thNight
31%8%10%17%26%8%
1552
21st to endNight
35%8%12%18%22%5%
1552
June1st to 10thNight
27%9%11%18%24%11%
1440
11th to 20thNight
22%6%8%14%30%21%
1440
21st to endNight
17%5%7%13%25%33%
1440
July1st to 10thNight
19%8%5%10%20%39%
1400
11th to 20thNight
20%5%6%12%20%37%
1544
21st to endNight
22%6%9%12%20%31%
1674
August1st to 10thNight
28%6%6%15%16%29%
1602
11th to 20thNight
17%37%12%23%38%
1775
21st to endNight
18%6%6%15%25%31%
1980
September1st to 10thNight
14%5%48%24%46%
1800
11th to 20thNight
20%6%5%18%28%23%
1800
21st to endNight
15%45%16%36%24%
2019
October1st to 10thNight
20%410%16%23%27%
2160
11th to 20thNight
24%5%7%17%22%25%
2160
21st to endNight
22%46%19%25%24%
2376
November1st to 10thNight
27%5%9%20%23%16%
2271
11th to 20thNight
29%6%10%19%26%10%
2470
21st to endNight
28%410%17%25%16%
2527
December1st to 10thNight
33%7%10%18%19%13%
2660
11th to 20thNight
51%6%9%14%15%5%
3276
21st to endNight
46%10%12%16%11%5%
4862

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
24%11%24%25%14%1
279
11th to 20thDay
13%11%22%34%19%1
353
21st to endDay
17%6%27%28%20%2
374
February1st to 10thDay
18%11%24%22%21%5%
340
11th to 20thDay
15%14%27%29%13%2
399
21st to endDay
14%15%29%28%11%3
346
March1st to 10thDay
20%15%30%25%10%1
420
11th to 20thDay
19%14%29%23%11%4
420
21st to endDay
14%18%33%23%10%1
462
April1st to 10thDay
13%16%33%23%13%2
420
11th to 20thDay
12%20%30%24%11%2
412
21st to endDay
7%17%29%29%12%5%
420
May1st to 10thDay
9%16%33%28%11%4
423
11th to 20thDay
8%15%33%28%10%5%
448
21st to endDay
10%14%31%29%12%5%
485
June1st to 10thDay
6%6%36%29%17%8%
450
11th to 20thDay
310%31%33%16%7%
450
21st to endDay
36%28%35%22%6%
450
July1st to 10thDay
1325%43%22%7%
446
11th to 20thDay
214%49%25%10%
444
21st to endDay
120%43%24%12%
487
August1st to 10thDay
35%26%40%19%8%
447
11th to 20thDay
222%40%23%12%
437
21st to endDay
1119%43%26%9%
495
September1st to 10thDay
2418%40%24%12%
450
11th to 20thDay
46%28%34%21%7%
450
21st to endDay
5%6%19%37%25%9%
450
October1st to 10thDay
5%8%24%34%22%7%
450
11th to 20thDay
6%7%23%29%26%10%
450
21st to endDay
8%7%20%34%23%8%
495
November1st to 10thDay
7%9%19%32%26%7%
403
11th to 20thDay
6%418%35%29%8%
270
21st to endDay
9%323%35%24%5%
241
December1st to 10thDay
14%9%20%33%20%4
180
11th to 20thDay
16%8%21%24%24%6%
180
21st to endDay
18%9%25%28%17%3
198
January1st to 10thNight
15%7%14%36%21%8%
760
11th to 20thNight
12%5%13%36%26%8%
738
21st to endNight
16%5%13%36%25%5%
792
February1st to 10thNight
17%413%35%25%6%
720
11th to 20thNight
14%5%17%34%23%7%
704
21st to endNight
14%7%15%41%20%4
592
March1st to 10thNight
15%7%18%34%21%5%
720
11th to 20thNight
14%417%35%23%6%
720
21st to endNight
13%7%18%37%22%4
792
April1st to 10thNight
12%5%15%40%25%3
720
11th to 20thNight
9%9%21%32%23%6%
711
21st to endNight
7%8%19%31%27%8%
720
May1st to 10thNight
6%5%19%35%27%8%
720
11th to 20thNight
8%5%13%35%30%9%
489
21st to endNight
7%7%17%31%30%7%
389
June1st to 10thNight
7%414%34%34%8%
360
11th to 20thNight
4214%39%36%6%
360
21st to endNight
245%31%49%8%
360
July1st to 10thNight
137%24%55%11%
350
11th to 20thNight
36%17%52%22%
500
21st to endNight
219%15%55%20%
591
August1st to 10thNight
429%22%50%13%
537
11th to 20thNight
227%31%46%13%
707
21st to endNight
217%23%52%16%
792
September1st to 10thNight
226%24%51%15%
720
11th to 20thNight
5%37%29%43%12%
720
21st to endNight
427%29%42%16%
720
October1st to 10thNight
6%28%36%35%13%
720
11th to 20thNight
8%310%32%35%13%
720
21st to endNight
6%310%33%30%18%
792
November1st to 10thNight
8%412%35%29%11%
740
11th to 20thNight
12%211%35%32%9%
760
21st to endNight
8%215%40%28%7%
760
December1st to 10thNight
13%5%13%37%25%6%
760
11th to 20thNight
18%7%14%35%23%4
760
21st to endNight
18%6%19%35%18%4
836
Page generated at 2024-01-12 04:31:46. Version ac07

Copyright 2024 Attilla Danko


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