Breckenridge
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Breckenridge clear sky chart from 2005-11-05 to 2018-04-23.

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
39%
16833
23%
49545
12%
16786
49%
16786
31%
28449

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
26%
965
21%
2706
8%
960
38%
960
27%
1588
January16th to endNight
26%
832
26%
2704
13%
832
43%
832
30%
1469
February1st to 15thNight
20%
762
16%
2472
5%
758
34%
758
22%
1503
February16th to endNight
21%
684
23%
2050
6%
684
39%
684
28%
1198
March1st to 15thNight
30%
780
22%
2243
9%
780
41%
780
33%
1266
March16th to endNight
26%
767
21%
2223
9%
767
38%
767
27%
1339
April1st to 15thNight
27%
584
19%
1948
9%
584
41%
584
25%
1094
April16th to endNight
31%
558
20%
1859
11%
558
43%
558
24%
1106
May1st to 15thNight
34%
540
17%
1612
8%
540
44%
540
26%
1023
May16th to endNight
46%
563
18%
1498
10%
561
53%
561
32%
908
June1st to 15thNight
51%
540
24%
1440
14%
540
60%
540
48%
745
June16th to endNight
65%
540
27%
1440
20%
540
70%
540
53%
737
July1st to 15thNight
70%
510
16%
1360
13%
510
72%
510
32%
866
July16th to endNight
74%
564
16%
1498
15%
531
75%
531
32%
915
August1st to 15thNight
65%
539
15%
1638
14%
536
67%
536
31%
962
August16th to endNight
68%
573
24%
1910
24%
573
72%
573
31%
1101
September1st to 15thNight
67%
540
27%
1800
24%
540
74%
540
34%
992
September16th to endNight
60%
573
31%
1941
23%
573
71%
573
40%
984
October1st to 15thNight
41%
720
26%
2160
14%
720
50%
720
39%
1136
October16th to endNight
42%
768
33%
2304
15%
768
56%
768
38%
1221
November1st to 15thNight
35%
941
28%
2461
11%
941
46%
941
39%
1362
November16th to endNight
32%
975
29%
2636
12%
975
45%
975
38%
1449
December1st to 15thNight
20%
975
17%
2730
4%
975
32%
975
26%
1653
December16th to endNight
23%
1040
20%
2912
8%
1040
34%
1040
22%
1832

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
5%7%48%7%35%45%7%42%
49984
Night
1325%5%35%5%6%8%51%
49724
TransparencyDay
40%6%13%20%15%4
49665
Night
26%8%18%25%17%3
49545
SeeingDay
15%23%28%19%10%2
6512
Night
5%18%31%27%15%2
16835

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
239%8%47%45%9%44%
1572
16th to endDay
449%8%2435%7%49%
1872
February1st to 15thDay
3413%9%35%46%7%41%
1721
16th to endDay
3412%8%5%6%446%43%
1710
March1st to 15thDay
7%47%8%45%446%45%
2044
16th to endDay
18%6%10%7%45%45%7%38%
2353
April1st to 15thDay
19%5%9%7%35%45%5%40%
2330
16th to endDay
314%6%11%8%45%446%30%
2215
May1st to 15thDay
5%15%5%9%7%35%5%5%6%31%
2334
16th to endDay
7%12%49%6%35%45%8%32%
2616
June1st to 15thDay
7%6%35%4245%6%8%44%
2520
16th to endDay
4425%435%5%5%6%53%
2520
July1st to 15thDay
11%6%37%7%35%5%47%35%
2520
16th to endDay
11%6%48%8%5%6%5%5%7%30%
2564
August1st to 15thDay
14%8%49%6%45%446%30%
2313
16th to endDay
10%7%38%7%45%5%6%7%34%
2292
September1st to 15thDay
11%6%36%5%24345%46%
2160
16th to endDay
5%7%27%5%33335%50%
2018
October1st to 15thDay
47%36%5%33346%50%
1800
16th to endDay
36%26%5%24346%53%
1917
November1st to 15thDay
426%5%2336%7%57%
1718
16th to endDay
335%6%23438%58%
1651
December1st to 15thDay
328%7%5%6%5%6%10%43%
1560
16th to endDay
35%9%9%47%46%8%40%
1664
January1st to 15thNight
1246%36%5%8%11%48%
2706
16th to endNight
225%6%37%45%8%52%
2704
February1st to 15thNight
226%8%46%8%7%9%44%
2461
16th to endNight
138%7%46%5%6%9%45%
2050
March1st to 15thNight
3246%35%46%8%54%
2243
16th to endNight
15%47%6%34447%51%
2223
April1st to 15thNight
5%35%6%36%5%5%9%49%
1948
16th to endNight
210%26%5%35%448%46%
1859
May1st to 15thNight
48%35%6%3446%8%43%
1611
16th to endNight
36%35%5%35%46%9%48%
1497
June1st to 15thNight
221232345%9%62%
1440
16th to endNight
121332436%7%64%
1440
July1st to 15thNight
4325%5%37%6%8%9%44%
1440
16th to endNight
5%3245%35%5%7%10%45%
1601
August1st to 15thNight
5%5%25%415%5%6%9%46%
1647
16th to endNight
6%4245%345%6%9%48%
1910
September1st to 15thNight
44244345%5%7%53%
1800
16th to endNight
13235%34447%59%
1941
October1st to 15thNight
242333445%7%57%
2160
16th to endNight
15%24423345%61%
2304
November1st to 15thNight
214435%46%7%60%
2461
16th to endNight
225%5%2445%8%57%
2636
December1st to 15thNight
226%7%35%47%10%49%
2730
16th to endNight
227%8%46%6%5%12%43%
2912

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%10%22%20%11%3
1573
16th to endDay
31%7%20%22%14%3
1872
February1st to 15thDay
40%10%17%19%9%2
1721
16th to endDay
38%5%15%21%16%2
1710
March1st to 15thDay
36%6%15%24%15%1
2044
16th to endDay
42%6%13%24%9%2
2353
April1st to 15thDay
42%6%14%20%11%4
2330
16th to endDay
53%5%11%20%7%1
2215
May1st to 15thDay
51%6%11%20%9%
2334
16th to endDay
48%6%12%19%10%1
2620
June1st to 15thDay
36%411%18%21%7%
2520
16th to endDay
30%47%22%25%9%
2520
July1st to 15thDay
47%6%10%13%14%7%
2371
16th to endDay
51%8%14%13%9%3
2404
August1st to 15thDay
54%7%9%11%13%4
2298
16th to endDay
47%6%11%18%13%3
2292
September1st to 15thDay
41%49%16%21%8%
2160
16th to endDay
35%310%24%23%2
2018
October1st to 15thDay
34%39%24%22%4
1800
16th to endDay
29%5%10%28%21%4
1917
November1st to 15thDay
24%6%16%21%25%6%
1718
16th to endDay
24%6%15%30%16%5%
1651
December1st to 15thDay
33%10%18%24%11%1
1560
16th to endDay
39%10%14%19%13%3
1664
January1st to 15thNight
22%13%23%23%13%2
2706
16th to endNight
24%8%21%24%16%4
2704
February1st to 15thNight
29%12%20%23%11%2
2472
16th to endNight
28%7%18%23%18%3
2050
March1st to 15thNight
23%8%18%29%16%2
2243
16th to endNight
31%6%17%30%11%2
2223
April1st to 15thNight
29%8%17%27%14%2
1948
16th to endNight
34%7%17%26%12%1
1859
May1st to 15thNight
36%7%16%26%11%
1612
16th to endNight
31%6%17%28%13%2
1498
June1st to 15thNight
18%5%16%27%23%7%
1440
16th to endNight
18%412%26%27%11%
1440
July1st to 15thNight
31%11%15%17%16%7%
1360
16th to endNight
30%10%22%20%11%3
1498
August1st to 15thNight
32%7%20%18%14%5%
1638
16th to endNight
31%7%16%24%17%2
1910
September1st to 15thNight
28%7%14%21%20%7%
1800
16th to endNight
23%5%14%32%21%2
1941
October1st to 15thNight
22%5%15%28%22%5%
2160
16th to endNight
23%5%12%31%22%4
2304
November1st to 15thNight
20%7%15%25%24%5%
2461
16th to endNight
22%5%16%29%20%4
2636
December1st to 15thNight
27%11%22%22%14%2
2730
16th to endNight
31%11%20%20%13%2
2912

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
15%26%27%19%9%1
135
16th to endDay
7%34%31%22%2
144
February1st to 15thDay
22%35%31%10%
135
16th to endDay
21%30%24%21%1
120
March1st to 15thDay
20%34%25%17%2
229
16th to endDay
17%40%30%9%1
352
April1st to 15thDay
18%44%25%7%11
329
16th to endDay
22%44%21%8%2
288
May1st to 15thDay
18%22%33%16%7%1
375
16th to endDay
17%20%28%19%10%3
517
June1st to 15thDay
10%20%26%23%17%3
495
16th to endDay
6%13%30%24%21%3
495
July1st to 15thDay
14%7%23%25%21%7%
475
16th to endDay
16%6%24%23%20%8%
423
August1st to 15thDay
21%13%24%27%10%2
315
16th to endDay
16%8%32%27%11%2
332
September1st to 15thDay
16%18%35%19%6%2
315
16th to endDay
14%18%34%19%8%4
210
October1st to 15thDay
11%25%24%23%11%3
135
16th to endDay
15%27%24%20%10%2
144
November1st to 15thDay
10%33%20%19%13%2
135
16th to endDay
17%31%36%13%1
135
December1st to 15thDay
15%36%34%11%2
135
16th to endDay
12%42%26%13%5%
144
January1st to 15thNight
8%29%31%19%9%1
965
16th to endNight
5%23%40%21%8%1
832
February1st to 15thNight
5%28%40%19%5%
764
16th to endNight
427%40%21%4
684
March1st to 15thNight
5%21%37%27%8%
780
16th to endNight
5%24%40%24%5%
767
April1st to 15thNight
6%22%40%23%6%
584
16th to endNight
7%22%34%26%8%
558
May1st to 15thNight
9%13%35%29%11%
540
16th to endNight
7%12%27%32%18%1
563
June1st to 15thNight
38%30%35%19%1
540
16th to endNight
3421%40%28%1
540
July1st to 15thNight
5%112%35%42%3
510
16th to endNight
5%17%32%46%6%
564
August1st to 15thNight
9%12%35%37%3
539
16th to endNight
7%213%34%36%6%
573
September1st to 15thNight
5%117%42%26%5%
540
16th to endNight
46%23%35%25%4
573
October1st to 15thNight
416%34%26%13%3
720
16th to endNight
416%32%28%14%3
768
November1st to 15thNight
6%21%33%27%9%1
941
16th to endNight
425%35%26%7%1
975
December1st to 15thNight
5%30%39%18%4
975
16th to endNight
6%29%33%22%7%
1040
Page generated at 2018-04-24 08:03:02. Version ac04

Copyright 2018 A. Danko


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