Lac Lovering
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lac Lovering clear sky chart from 2005-11-05 to 2017-09-22.

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
27%
14686
11%
46883
7%
14655
32%
14655
14%
35069

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
14%
720
6%
2506
4%
716
18%
716
6%
2064
January16th to endNight
16%
768
7%
2688
4%
768
21%
768
7%
2202
February1st to 15thNight
16%
704
6%
2300
3%
701
19%
701
7%
1928
February16th to endNight
18%
631
9%
1893
5%
631
23%
631
9%
1519
March1st to 15thNight
20%
720
13%
2160
9%
720
26%
720
12%
1673
March16th to endNight
26%
768
17%
2014
7%
768
33%
768
17%
1522
April1st to 15thNight
22%
718
14%
1796
4%
718
28%
718
16%
1418
April16th to endNight
26%
582
16%
1662
6%
582
32%
582
18%
1166
May1st to 15thNight
28%
465
15%
1545
11%
465
36%
465
17%
1066
May16th to endNight
33%
374
11%
1497
10%
374
41%
374
14%
1027
June1st to 15thNight
31%
360
8%
1440
8%
360
38%
360
12%
1021
June16th to endNight
43%
360
8%
1440
11%
360
48%
360
18%
925
July1st to 15thNight
46%
340
11%
1360
16%
340
50%
340
20%
837
July16th to endNight
53%
376
11%
1418
15%
354
55%
354
21%
851
August1st to 15thNight
52%
418
13%
1489
14%
416
54%
416
21%
956
August16th to endNight
53%
705
19%
1851
12%
705
56%
705
34%
1186
September1st to 15thNight
44%
720
12%
1830
6%
720
46%
720
27%
1267
September16th to endNight
44%
685
20%
1891
14%
685
48%
685
31%
1190
October1st to 15thNight
31%
660
16%
1891
9%
660
38%
660
18%
1375
October16th to endNight
21%
704
8%
2288
5%
704
27%
704
11%
1781
November1st to 15thNight
21%
700
13%
2277
9%
700
27%
700
12%
1718
November16th to endNight
21%
720
12%
2439
9%
720
26%
720
10%
1894
December1st to 15thNight
13%
720
4%
2520
1%
720
17%
720
5%
2162
December16th to endNight
10%
768
6%
2688
3%
768
14%
768
4%
2321

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%11%47%6%34446%27%
48006
Night
18%11%48%6%34445%27%
47053
Cloud CoverDay
20%11%47%6%34446%26%
48016
Night
18%12%48%6%34445%27%
47058
TransparencyDay
58%411%18%7%
47694
Night
58%410%17%7%
46883
SeeingDay
27%13%26%19%10%3
5703
Night
26%13%25%23%9%
14687

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 15thDay
17%15%6%13%9%5%6%43312%
1432
16th to endDay
11%15%7%10%9%46%5%5%5%18%
1536
February1st to 15thDay
12%16%9%14%9%5%6%44313%
1557
16th to endDay
12%17%7%12%8%45%34418%
1580
March1st to 15thDay
16%15%6%8%7%3444423%
1790
16th to endDay
18%13%5%9%6%2323331%
2208
April1st to 15thDay
20%15%5%7%5%23335%27%
2152
16th to endDay
20%10%36%5%34435%32%
2298
May1st to 15thDay
22%8%36%7%2435%6%29%
2416
16th to endDay
20%7%36%6%35%5%6%6%28%
2618
June1st to 15thDay
28%7%25%5%3445%6%25%
2520
16th to endDay
20%7%35%5%35%5%5%7%29%
2520
July1st to 15thDay
16%6%36%6%35%5%6%9%31%
2520
16th to endDay
17%5%35%6%35%6%6%9%29%
2654
August1st to 15thDay
18%6%36%7%36%6%6%8%26%
2448
16th to endDay
15%6%25%445%45%8%37%
2350
September1st to 15thDay
20%6%25%424346%38%
2130
16th to endDay
17%6%24424448%40%
1881
October1st to 15thDay
23%11%35%5%33346%28%
1737
16th to endDay
24%17%45%5%3433323%
1584
November1st to 15thDay
19%14%46%5%33446%26%
1581
16th to endDay
18%16%5%9%5%24345%24%
1518
December1st to 15thDay
21%20%7%10%6%4343315%
1440
16th to endDay
22%19%9%11%7%2423312%
1536
January1st to 15thNight
14%16%7%12%8%45%35%416%
2506
16th to endNight
10%15%7%11%10%47%5%4418%
2688
February1st to 15thNight
11%14%6%15%11%45%44316%
2299
16th to endNight
14%15%7%10%6%46%42423%
1893
March1st to 15thNight
19%12%6%7%7%24435%26%
2147
16th to endNight
16%12%5%7%6%3432432%
2014
April1st to 15thNight
21%12%46%6%25%43328%
1796
16th to endNight
20%9%26%5%24346%35%
1662
May1st to 15thNight
19%9%36%6%24447%32%
1545
16th to endNight
20%6%35%5%35%45%7%32%
1495
June1st to 15thNight
28%7%25%42435%8%28%
1440
16th to endNight
17%6%35%4245%7%9%33%
1440
July1st to 15thNight
14%5%345%26%5%5%10%34%
1440
16th to endNight
12%5%25%4445%6%8%39%
1514
August1st to 15thNight
14%5%25%5%35%6%6%9%37%
1499
16th to endNight
12%415%434448%46%
1851
September1st to 15thNight
18%5%25%434446%40%
1830
16th to endNight
19%42331335%7%45%
1891
October1st to 15thNight
21%9%36%5%24346%32%
1891
16th to endNight
25%11%36%6%34445%23%
2288
November1st to 15thNight
19%12%46%7%44346%26%
2277
16th to endNight
19%13%5%9%6%3443426%
2439
December1st to 15thNight
21%19%7%11%6%2433313%
2520
16th to endNight
20%20%8%9%7%3442413%
2688

Percentage Cloud Cover SE (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
16%16%6%13%9%46%43313%
1432
16th to endDay
11%17%6%10%10%36%5%45%18%
1536
February1st to 15thDay
11%17%9%14%10%5%7%32313%
1557
16th to endDay
12%17%8%12%8%5%5%33417%
1580
March1st to 15thDay
17%15%6%9%7%35%43323%
1800
16th to endDay
18%15%5%9%5%2222430%
2208
April1st to 15thDay
21%14%5%7%5%2323427%
2152
16th to endDay
21%10%25%5%24445%31%
2298
May1st to 15thDay
24%8%36%5%3435%5%29%
2416
16th to endDay
22%6%36%6%345%6%6%27%
2618
June1st to 15thDay
30%7%35%5%3445%6%24%
2520
16th to endDay
21%7%36%5%26%5%5%7%28%
2520
July1st to 15thDay
17%6%45%6%35%5%5%9%30%
2520
16th to endDay
17%7%25%6%35%6%7%9%28%
2654
August1st to 15thDay
18%7%27%6%36%6%6%8%26%
2448
16th to endDay
16%6%25%5%25%45%8%36%
2350
September1st to 15thDay
22%6%24424346%38%
2130
16th to endDay
18%6%2442435%8%40%
1881
October1st to 15thDay
24%11%25%424445%28%
1737
16th to endDay
25%19%35%5%2434322%
1584
November1st to 15thDay
21%14%46%423445%26%
1581
16th to endDay
17%17%7%8%5%2434424%
1518
December1st to 15thDay
20%20%9%9%6%3433316%
1440
16th to endDay
22%21%8%11%6%3432212%
1536
January1st to 15thNight
14%17%7%12%8%46%34415%
2506
16th to endNight
10%18%7%12%9%5%7%43416%
2688
February1st to 15thNight
11%14%7%16%11%5%5%43315%
2292
16th to endNight
14%17%7%11%7%35%32322%
1893
March1st to 15thNight
19%14%5%8%7%2433426%
2160
16th to endNight
17%13%6%7%5%3432431%
2013
April1st to 15thNight
21%14%46%5%3444327%
1796
16th to endNight
21%9%26%424225%36%
1662
May1st to 15thNight
20%8%46%5%23446%32%
1545
16th to endNight
21%6%36%5%4435%6%31%
1495
June1st to 15thNight
29%6%35%42445%7%27%
1440
16th to endNight
19%6%24325%5%6%8%34%
1440
July1st to 15thNight
15%5%25%5%35%5%5%10%34%
1440
16th to endNight
13%5%25%5%35%5%6%8%39%
1514
August1st to 15thNight
16%5%345%25%5%5%9%36%
1499
16th to endNight
14%425%32435%7%46%
1851
September1st to 15thNight
19%5%245%34436%39%
1830
16th to endNight
19%41331235%7%45%
1891
October1st to 15thNight
23%9%36%423445%32%
1891
16th to endNight
28%13%35%5%34445%22%
2288
November1st to 15thNight
20%13%36%7%44346%25%
2277
16th to endNight
19%14%6%10%5%2433325%
2439
December1st to 15thNight
21%20%7%11%7%3433314%
2520
16th to endNight
20%21%7%10%7%35%32311%
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
75%47%10%2
1433
16th to endDay
67%310%14%3
1536
February1st to 15thDay
76%27%11%2
1560
16th to endDay
69%37%10%7%1
1580
March1st to 15thDay
65%39%14%6%1
1800
16th to endDay
60%27%17%10%1
2208
April1st to 15thDay
60%27%17%10%1
2152
16th to endDay
53%48%19%11%3
2298
May1st to 15thDay
56%38%19%11%
2416
16th to endDay
54%5%11%18%9%
2622
June1st to 15thDay
58%412%17%6%
2520
16th to endDay
52%6%11%21%7%
2520
July1st to 15thDay
47%6%14%24%7%
2371
16th to endDay
49%6%16%22%4
2487
August1st to 15thDay
53%6%17%18%4
2434
16th to endDay
43%5%16%24%10%
2350
September1st to 15thDay
46%411%26%9%
2130
16th to endDay
42%313%26%12%
1881
October1st to 15thDay
56%312%19%7%
1737
16th to endDay
66%311%14%4
1584
November1st to 15thDay
59%411%15%7%1
1581
16th to endDay
63%312%13%6%
1518
December1st to 15thDay
73%49%10%2
1440
16th to endDay
78%36%6%4
1536
January1st to 15thNight
71%310%10%2
2506
16th to endNight
70%37%13%4
2688
February1st to 15thNight
73%38%11%3
2300
16th to endNight
67%38%11%8%
1893
March1st to 15thNight
62%38%18%6%1
2160
16th to endNight
57%27%16%12%2
2014
April1st to 15thNight
61%35%16%12%
1796
16th to endNight
51%39%19%13%2
1662
May1st to 15thNight
51%47%19%15%1
1545
16th to endNight
52%5%11%20%8%1
1497
June1st to 15thNight
56%410%20%6%
1440
16th to endNight
44%7%14%23%9%
1440
July1st to 15thNight
41%8%16%24%8%
1360
16th to endNight
41%5%18%24%9%
1418
August1st to 15thNight
42%6%20%23%6%
1489
16th to endNight
36%418%28%11%
1851
September1st to 15thNight
45%414%25%9%
1830
16th to endNight
37%414%29%12%
1891
October1st to 15thNight
53%411%20%9%
1891
16th to endNight
63%410%15%5%
2288
November1st to 15thNight
60%411%14%6%2
2277
16th to endNight
64%39%16%5%
2439
December1st to 15thNight
76%38%9%2
2520
16th to endNight
78%36%7%3
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
21%20%31%18%8%
60
16th to endDay
32%20%28%15%11
64
February1st to 15thDay
27%25%27%12%6%
133
16th to endDay
26%21%27%17%5%1
239
March1st to 15thDay
33%20%20%20%5%
270
16th to endDay
29%17%23%15%11%2
288
April1st to 15thDay
35%15%23%18%42
270
16th to endDay
28%15%29%13%9%3
270
May1st to 15thDay
38%11%25%12%9%3
288
16th to endDay
23%18%26%23%7%1
331
June1st to 15thDay
38%7%26%18%9%
315
16th to endDay
22%11%36%20%7%
315
July1st to 15thDay
21%9%31%23%9%4
305
16th to endDay
17%7%31%28%12%1
326
August1st to 15thDay
20%7%31%22%14%4
313
16th to endDay
20%9%20%22%18%8%
332
September1st to 15thDay
23%5%22%21%17%9%
315
16th to endDay
17%11%19%22%18%11%
278
October1st to 15thDay
29%14%21%12%16%4
254
16th to endDay
40%13%20%17%7%
240
November1st to 15thDay
28%14%28%18%7%1
235
16th to endDay
32%18%21%15%9%2
138
December1st to 15thDay
41%16%21%15%31
60
16th to endDay
46%17%29%6%
64
January1st to 15thNight
24%20%31%18%4
720
16th to endNight
22%20%31%20%5%
768
February1st to 15thNight
21%18%31%24%4
704
16th to endNight
25%17%29%22%4
631
March1st to 15thNight
31%14%26%21%4
720
16th to endNight
25%18%25%20%8%1
768
April1st to 15thNight
30%15%26%23%4
718
16th to endNight
28%14%25%21%9%
582
May1st to 15thNight
26%11%29%23%8%1
465
16th to endNight
23%8%27%30%9%
375
June1st to 15thNight
33%6%20%27%11%
360
16th to endNight
18%6%26%36%11%
360
July1st to 15thNight
16%423%35%19%1
340
16th to endNight
14%222%40%19%
376
August1st to 15thNight
19%317%36%22%
418
16th to endNight
16%320%34%23%2
705
September1st to 15thNight
22%7%19%34%15%1
720
16th to endNight
21%7%24%24%19%2
685
October1st to 15thNight
31%10%21%22%13%1
660
16th to endNight
35%13%24%20%5%
704
November1st to 15thNight
25%15%30%19%7%1
700
16th to endNight
28%18%24%16%9%2
720
December1st to 15thNight
34%17%28%14%4
720
16th to endNight
35%17%26%15%3
768
Page generated at 2017-09-23 06:43:47. Version ac04

Copyright 2017 A. Danko


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