Loveland Pass
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Loveland Pass clear sky chart from 2005-11-05 to 2017-09-15.

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
33%
15930
21%
46861
10%
15883
44%
15883
26%
27329

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
20%
900
20%
2506
6%
895
33%
895
21%
1497
January16th to endNight
19%
771
24%
2499
10%
771
36%
771
23%
1370
February1st to 15thNight
15%
701
15%
2275
4%
697
29%
697
16%
1367
February16th to endNight
14%
632
21%
1894
3%
632
33%
632
19%
1132
March1st to 15thNight
22%
720
21%
2079
5%
720
36%
720
23%
1230
March16th to endNight
20%
702
20%
2046
7%
702
33%
702
23%
1244
April1st to 15thNight
21%
539
19%
1798
6%
539
37%
539
22%
1016
April16th to endNight
25%
540
18%
1800
9%
540
38%
540
20%
1080
May1st to 15thNight
28%
540
16%
1606
5%
540
40%
540
22%
1029
May16th to endNight
41%
563
17%
1498
9%
561
49%
561
28%
928
June1st to 15thNight
46%
540
23%
1440
12%
540
55%
540
44%
768
June16th to endNight
61%
540
26%
1440
18%
540
68%
540
49%
749
July1st to 15thNight
66%
510
16%
1360
13%
510
68%
510
31%
863
July16th to endNight
70%
564
17%
1484
15%
531
72%
531
33%
894
August1st to 15thNight
64%
539
15%
1641
14%
536
67%
536
30%
981
August16th to endNight
66%
573
24%
1910
25%
573
70%
573
30%
1111
September1st to 15thNight
59%
540
27%
1800
21%
540
69%
540
33%
991
September16th to endNight
56%
517
30%
1777
22%
517
66%
517
37%
912
October1st to 15thNight
35%
660
26%
1980
13%
660
46%
660
32%
1077
October16th to endNight
33%
704
29%
2112
11%
704
48%
704
31%
1157
November1st to 15thNight
26%
875
27%
2275
8%
875
40%
875
32%
1299
November16th to endNight
23%
900
27%
2433
8%
900
37%
900
29%
1371
December1st to 15thNight
15%
900
16%
2520
3%
900
27%
900
18%
1527
December16th to endNight
17%
960
18%
2688
5%
960
28%
960
18%
1736

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%9%5%9%7%35%45%6%38%
47885
Night
25%37%7%35%45%7%46%
47039
TransparencyDay
43%6%12%19%14%4
47565
Night
29%7%17%25%16%4
46861
SeeingDay
20%21%27%18%10%2
5824
Night
9%22%29%24%12%1
15933

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
5%6%13%10%46%347%37%
1438
16th to endDay
6%6%13%8%34346%42%
1728
February1st to 15thDay
6%8%15%10%44446%33%
1588
16th to endDay
46%17%10%5%5%246%35%
1580
March1st to 15thDay
19%5%11%9%33346%41%
1879
16th to endDay
211%7%12%7%3445%6%34%
2178
April1st to 15thDay
213%7%12%6%25%345%35%
2150
16th to endDay
319%8%12%7%34445%26%
2160
May1st to 15thDay
7%16%6%8%8%34445%28%
2343
16th to endDay
8%13%48%7%35%5%5%6%29%
2616
June1st to 15thDay
8%8%245%35%46%8%42%
2520
16th to endDay
5%4245%35%5%6%6%50%
2520
July1st to 15thDay
10%7%48%7%35%5%5%6%35%
2520
16th to endDay
11%8%48%7%47%5%5%6%30%
2579
August1st to 15thDay
15%8%48%7%3445%6%30%
2310
16th to endDay
12%8%38%6%35%5%6%6%33%
2292
September1st to 15thDay
11%7%37%42433445%
2149
16th to endDay
7%10%36%323345%48%
1851
October1st to 15thDay
5%12%5%6%434246%44%
1650
16th to endDay
5%8%47%5%23346%47%
1749
November1st to 15thDay
18%48%5%3445%6%49%
1583
16th to endDay
6%48%8%2325%6%52%
1526
December1st to 15thDay
7%5%13%11%46%349%34%
1440
16th to endDay
6%5%14%12%6%5%35%6%32%
1536
January1st to 15thNight
349%11%5%6%5%5%6%39%
2506
16th to endNight
45%10%10%5%5%445%43%
2499
February1st to 15thNight
45%11%12%5%6%447%35%
2264
16th to endNight
35%14%10%46%347%39%
1894
March1st to 15thNight
449%7%45%45%7%46%
2079
16th to endNight
17%6%9%5%34346%46%
2046
April1st to 15thNight
6%49%8%35%45%7%44%
1798
16th to endNight
213%39%5%34437%41%
1800
May1st to 15thNight
410%38%5%35%5%6%7%40%
1605
16th to endNight
39%245%35%46%10%44%
1497
June1st to 15thNight
221232445%9%58%
1440
16th to endNight
231232345%7%62%
1440
July1st to 15thNight
43246%26%6%6%10%46%
1440
16th to endNight
43345%35%6%7%8%47%
1586
August1st to 15thNight
6%5%244345%6%9%47%
1650
16th to endNight
6%5%24425%5%7%8%48%
1910
September1st to 15thNight
44244345%6%7%52%
1800
16th to endNight
3425%42335%7%58%
1777
October1st to 15thNight
37%35%5%25%347%53%
1980
16th to endNight
27%26%5%23345%56%
2112
November1st to 15thNight
437%5%35%347%54%
2275
16th to endNight
349%7%23338%52%
2433
December1st to 15thNight
5%49%10%46%5%5%6%41%
2520
16th to endNight
4411%13%6%5%348%36%
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
34%9%21%19%11%2
1439
16th to endDay
36%6%17%22%12%3
1728
February1st to 15thDay
40%9%18%18%9%2
1588
16th to endDay
40%6%15%22%13%2
1580
March1st to 15thDay
38%7%13%25%13%1
1879
16th to endDay
45%5%11%24%9%3
2178
April1st to 15thDay
46%5%12%19%12%4
2150
16th to endDay
55%49%19%8%1
2160
May1st to 15thDay
53%6%9%19%9%
2343
16th to endDay
52%6%11%18%9%2
2620
June1st to 15thDay
39%6%10%15%20%7%
2520
16th to endDay
32%6%6%22%23%8%
2520
July1st to 15thDay
49%7%9%12%13%7%
2371
16th to endDay
52%7%12%14%8%3
2418
August1st to 15thDay
56%6%8%10%12%4
2295
16th to endDay
49%6%8%17%14%3
2292
September1st to 15thDay
42%47%15%20%8%
2149
16th to endDay
37%39%23%22%2
1851
October1st to 15thDay
37%5%8%24%21%3
1650
16th to endDay
33%5%9%26%21%4
1749
November1st to 15thDay
27%6%16%19%23%6%
1583
16th to endDay
27%5%16%28%16%5%
1526
December1st to 15thDay
37%9%18%23%10%1
1440
16th to endDay
41%10%14%19%10%3
1536
January1st to 15thNight
26%11%23%22%13%2
2506
16th to endNight
26%8%22%23%14%5%
2499
February1st to 15thNight
32%10%20%23%11%2
2275
16th to endNight
31%6%18%23%16%3
1894
March1st to 15thNight
27%9%16%28%14%3
2079
16th to endNight
32%6%16%29%11%2
2046
April1st to 15thNight
30%7%16%27%14%3
1798
16th to endNight
35%7%16%26%13%
1800
May1st to 15thNight
38%7%16%24%11%
1606
16th to endNight
33%7%17%26%12%2
1498
June1st to 15thNight
20%6%16%25%22%7%
1440
16th to endNight
20%411%28%24%10%
1440
July1st to 15thNight
34%8%15%19%15%7%
1360
16th to endNight
31%7%21%22%11%4
1484
August1st to 15thNight
34%6%19%19%14%5%
1641
16th to endNight
31%8%14%25%18%2
1910
September1st to 15thNight
29%6%13%21%20%8%
1800
16th to endNight
23%6%13%32%21%2
1777
October1st to 15thNight
24%6%15%28%20%4
1980
16th to endNight
25%6%12%29%22%3
2112
November1st to 15thNight
23%6%15%25%22%7%
2275
16th to endNight
25%5%14%29%19%4
2433
December1st to 15thNight
27%11%23%22%12%1
2520
16th to endNight
34%9%20%20%12%2
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
20%23%26%14%14%1
90
16th to endDay
12%35%31%19%1
96
February1st to 15thDay
25%42%24%6%1
90
16th to endDay
23%28%27%17%3
81
March1st to 15thDay
24%34%23%15%1
169
16th to endDay
18%42%29%8%
288
April1st to 15thDay
24%37%24%8%21
269
16th to endDay
28%42%19%7%1
270
May1st to 15thDay
22%22%31%15%6%
387
16th to endDay
22%21%27%16%11%2
517
June1st to 15thDay
16%16%27%24%12%2
495
16th to endDay
8%11%31%26%18%2
495
July1st to 15thDay
18%7%23%26%18%5%
475
16th to endDay
18%5%24%23%19%7%
438
August1st to 15thDay
29%11%26%23%8%1
315
16th to endDay
24%9%28%26%9%2
332
September1st to 15thDay
21%18%34%15%8%1
312
16th to endDay
16%15%33%16%13%3
153
October1st to 15thDay
13%30%24%14%15%2
90
16th to endDay
23%21%27%18%7%1
96
November1st to 15thDay
12%24%18%23%15%5%
90
16th to endDay
22%31%36%8%1
90
December1st to 15thDay
22%43%25%7%1
90
16th to endDay
8%54%23%9%31
96
January1st to 15thNight
14%32%27%15%8%1
900
16th to endNight
11%28%36%17%5%
771
February1st to 15thNight
10%33%35%14%5%
704
16th to endNight
11%35%32%17%3
632
March1st to 15thNight
6%32%32%19%7%
720
16th to endNight
7%30%39%18%4
702
April1st to 15thNight
8%25%39%20%5%
539
16th to endNight
11%24%34%22%6%
540
May1st to 15thNight
11%16%36%26%9%
540
16th to endNight
12%12%27%31%14%1
563
June1st to 15thNight
6%10%32%34%15%
540
16th to endNight
45%22%44%22%1
540
July1st to 15thNight
9%111%39%35%2
510
16th to endNight
7%110%33%41%4
564
August1st to 15thNight
11%113%41%30%2
539
16th to endNight
8%214%38%30%5%
573
September1st to 15thNight
7%321%39%22%5%
540
16th to endNight
5%8%24%33%24%3
517
October1st to 15thNight
8%21%32%21%13%1
660
16th to endNight
9%23%30%23%11%2
704
November1st to 15thNight
9%28%32%20%9%
875
16th to endNight
11%29%33%19%6%
900
December1st to 15thNight
10%40%31%14%3
900
16th to endNight
12%31%32%17%5%
960
Page generated at 2017-09-15 22:58:32. Version ac04

Copyright 2017 A. Danko


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