Mew Lake Campground
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mew Lake Campground clear sky chart from 2005-11-05 to

2017-09-12
.

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
24%
14640
12%
46525
6%
14608
31%
14608
14%
34424

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
9%
720
4%
2506
1%
716
12%
716
4%
2128
January16th to endNight
17%
768
10%
2553
5%
768
23%
768
9%
2036
February1st to 15thNight
12%
704
8%
2287
3%
701
18%
701
8%
1858
February16th to endNight
15%
631
11%
2027
5%
631
23%
631
10%
1556
March1st to 15thNight
15%
720
12%
2005
4%
720
22%
720
12%
1547
March16th to endNight
26%
768
19%
2102
8%
768
36%
768
22%
1454
April1st to 15thNight
19%
718
15%
1796
5%
718
24%
718
18%
1355
April16th to endNight
29%
573
17%
1653
8%
573
35%
573
20%
1171
May1st to 15thNight
33%
411
17%
1491
13%
411
42%
411
18%
980
May16th to endNight
32%
374
13%
1497
8%
374
45%
374
18%
938
June1st to 15thNight
31%
360
9%
1422
7%
360
39%
360
16%
936
June16th to endNight
39%
360
10%
1260
9%
360
46%
360
20%
833
July1st to 15thNight
42%
340
15%
1256
17%
340
49%
340
28%
712
July16th to endNight
43%
385
14%
1427
13%
363
51%
363
24%
854
August1st to 15thNight
50%
539
14%
1609
10%
536
54%
536
26%
1035
August16th to endNight
45%
633
17%
1779
8%
633
51%
633
31%
1110
September1st to 15thNight
38%
707
14%
1768
6%
707
42%
707
28%
1219
September16th to endNight
39%
657
18%
1829
11%
657
44%
657
27%
1205
October1st to 15thNight
26%
660
16%
1980
9%
660
35%
660
17%
1434
October16th to endNight
16%
704
8%
2126
3%
704
22%
704
9%
1723
November1st to 15thNight
22%
700
14%
2424
10%
700
30%
700
12%
1776
November16th to endNight
17%
720
8%
2520
6%
720
21%
720
8%
2071
December1st to 15thNight
10%
720
6%
2520
1%
720
15%
720
5%
2179
December16th to endNight
8%
768
6%
2688
2%
768
13%
768
4%
2314

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
18%11%47%6%34446%28%
48137
Night
16%12%5%8%6%34445%28%
46692
Cloud CoverDay
18%11%47%6%34446%28%
48147
Night
16%12%5%8%6%34445%29%
46697
TransparencyDay
57%5%10%17%8%1
47822
Night
56%5%10%17%9%
46525
SeeingDay
24%14%30%20%7%2
5606
Night
23%15%31%21%7%
14641

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
18%16%8%11%8%2435%416%
1432
16th to endDay
12%16%7%12%7%36%5%46%18%
1668
February1st to 15thDay
10%16%8%12%10%36%43417%
1575
16th to endDay
15%17%6%10%8%25%445%19%
1446
March1st to 15thDay
15%14%6%10%7%45%34425%
1942
16th to endDay
12%10%5%8%6%33345%35%
2121
April1st to 15thDay
21%14%5%6%322336%29%
2152
16th to endDay
20%11%35%413335%37%
2318
May1st to 15thDay
20%10%36%5%34336%31%
2460
16th to endDay
17%7%35%5%3445%6%35%
2618
June1st to 15thDay
22%9%46%5%24447%27%
2535
16th to endDay
18%6%25%6%35%5%5%8%31%
2700
July1st to 15thDay
16%6%25%5%45%5%5%7%35%
2625
16th to endDay
13%6%36%6%45%6%5%9%31%
2643
August1st to 15thDay
16%6%36%7%45%5%5%7%31%
2340
16th to endDay
15%6%25%6%45%6%5%7%32%
2411
September1st to 15thDay
21%8%35%5%23446%34%
2112
16th to endDay
20%7%25%5%23436%38%
1798
October1st to 15thDay
25%11%46%5%24325%28%
1650
16th to endDay
31%15%5%6%5%2324417%
1744
November1st to 15thDay
18%13%5%9%5%34445%25%
1431
16th to endDay
22%18%8%11%5%3333415%
1440
December1st to 15thDay
19%22%8%12%8%3333410%
1440
16th to endDay
18%22%8%11%7%33335%12%
1536
January1st to 15thNight
16%18%7%12%9%45%43411%
2506
16th to endNight
12%15%8%10%9%45%5%35%19%
2553
February1st to 15thNight
10%14%8%12%9%5%5%446%17%
2285
16th to endNight
12%15%7%11%6%45%445%22%
2027
March1st to 15thNight
14%13%6%9%7%3443428%
1993
16th to endNight
11%10%5%7%5%24336%39%
2102
April1st to 15thNight
19%14%5%5%434235%32%
1796
16th to endNight
18%10%36%424446%35%
1653
May1st to 15thNight
19%8%36%423447%34%
1491
16th to endNight
14%7%26%434447%39%
1495
June1st to 15thNight
18%6%35%4245%46%35%
1422
16th to endNight
13%7%36%5%25%5%5%8%35%
1260
July1st to 15thNight
11%5%24423447%47%
1332
16th to endNight
10%5%25%435%5%5%8%43%
1523
August1st to 15thNight
11%5%244245%5%8%43%
1620
16th to endNight
10%425%435%45%8%44%
1779
September1st to 15thNight
15%6%25%3335%5%7%41%
1768
16th to endNight
17%7%24423336%43%
1829
October1st to 15thNight
21%10%35%434346%32%
1980
16th to endNight
26%16%47%42334420%
2126
November1st to 15thNight
18%12%5%7%5%2445%5%28%
2424
16th to endNight
20%18%6%9%7%3433418%
2520
December1st to 15thNight
18%21%8%12%7%3433313%
2520
16th to endNight
19%20%7%13%7%3433312%
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
18%16%8%11%8%3335%416%
1432
16th to endDay
12%15%7%12%6%36%5%45%18%
1668
February1st to 15thDay
10%16%8%13%10%36%44417%
1575
16th to endDay
15%17%6%10%8%25%445%19%
1446
March1st to 15thDay
16%13%6%9%7%45%43425%
1953
16th to endDay
12%10%49%6%33345%35%
2120
April1st to 15thDay
21%14%46%323335%29%
2152
16th to endDay
20%11%35%423235%37%
2318
May1st to 15thDay
20%9%46%5%34345%31%
2460
16th to endDay
16%8%36%5%3445%6%35%
2618
June1st to 15thDay
22%9%46%5%2435%6%28%
2535
16th to endDay
17%6%26%6%35%5%5%7%31%
2700
July1st to 15thDay
16%5%25%6%36%46%7%35%
2625
16th to endDay
13%6%36%6%36%5%5%9%31%
2643
August1st to 15thDay
16%7%38%7%445%5%6%31%
2340
16th to endDay
15%6%25%6%45%5%6%7%32%
2411
September1st to 15thDay
21%8%36%424446%34%
2112
16th to endDay
19%8%25%433446%37%
1798
October1st to 15thDay
24%11%45%5%33326%28%
1650
16th to endDay
30%16%47%5%3233417%
1744
November1st to 15thDay
18%13%5%9%6%3335%5%25%
1431
16th to endDay
22%18%8%10%6%2432416%
1440
December1st to 15thDay
18%23%8%12%8%3334310%
1440
16th to endDay
18%21%8%11%6%3334412%
1536
January1st to 15thNight
16%18%8%12%9%45%44412%
2506
16th to endNight
11%14%7%11%9%45%5%4420%
2553
February1st to 15thNight
10%15%7%11%9%5%5%5%5%5%17%
2278
16th to endNight
12%16%7%10%6%45%445%22%
2027
March1st to 15thNight
15%12%6%9%7%35%44427%
2005
16th to endNight
11%9%5%7%5%33336%39%
2102
April1st to 15thNight
19%14%46%42333433%
1796
16th to endNight
17%10%35%5%23445%35%
1653
May1st to 15thNight
19%8%35%424448%34%
1491
16th to endNight
13%7%36%4245%5%7%39%
1495
June1st to 15thNight
17%7%35%5%25%5%46%35%
1422
16th to endNight
13%6%36%5%26%46%7%35%
1260
July1st to 15thNight
10%5%2442345%7%47%
1332
16th to endNight
10%5%344346%5%7%43%
1523
August1st to 15thNight
11%5%244345%6%8%43%
1620
16th to endNight
10%425%5%3446%9%44%
1779
September1st to 15thNight
15%6%25%424448%40%
1768
16th to endNight
17%7%24423436%43%
1829
October1st to 15thNight
20%10%45%434346%33%
1980
16th to endNight
25%16%47%43434420%
2126
November1st to 15thNight
17%13%46%5%35%45%6%28%
2424
16th to endNight
20%17%6%9%7%3433418%
2520
December1st to 15thNight
18%20%8%11%7%3433313%
2520
16th to endNight
19%19%7%13%7%35%33412%
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
70%47%10%6%
1433
16th to endDay
66%47%12%6%2
1668
February1st to 15thDay
69%47%12%5%
1577
16th to endDay
66%37%12%9%
1446
March1st to 15thDay
63%311%13%6%1
1953
16th to endDay
50%48%17%15%3
2121
April1st to 15thDay
57%47%17%11%2
2152
16th to endDay
50%37%21%13%2
2318
May1st to 15thDay
55%39%17%12%1
2460
16th to endDay
48%6%10%20%11%2
2622
June1st to 15thDay
56%410%19%8%
2535
16th to endDay
50%6%11%19%10%1
2700
July1st to 15thDay
44%6%11%25%10%1
2472
16th to endDay
47%7%13%22%8%
2476
August1st to 15thDay
51%7%14%17%8%
2327
16th to endDay
47%7%13%23%7%
2411
September1st to 15thDay
51%5%12%20%10%
2112
16th to endDay
47%5%11%27%8%
1798
October1st to 15thDay
59%410%16%9%
1650
16th to endDay
70%48%10%5%
1744
November1st to 15thDay
60%5%12%15%6%
1431
16th to endDay
73%38%10%31
1440
December1st to 15thDay
78%46%8%2
1440
16th to endDay
74%37%9%4
1536
January1st to 15thNight
75%49%6%4
2506
16th to endNight
66%47%13%7%1
2553
February1st to 15thNight
67%5%9%11%5%
2287
16th to endNight
62%48%16%7%
2027
March1st to 15thNight
60%410%15%8%1
2005
16th to endNight
47%49%19%16%2
2102
April1st to 15thNight
56%36%19%13%1
1796
16th to endNight
50%47%20%15%1
1653
May1st to 15thNight
47%5%10%19%14%2
1491
16th to endNight
41%7%14%21%13%1
1497
June1st to 15thNight
48%5%12%20%12%
1422
16th to endNight
45%6%13%23%10%
1260
July1st to 15thNight
32%7%12%29%17%1
1256
16th to endNight
37%6%16%26%11%
1427
August1st to 15thNight
37%9%16%25%11%
1609
16th to endNight
34%7%19%28%9%
1779
September1st to 15thNight
41%6%16%24%10%
1768
16th to endNight
42%413%31%7%
1829
October1st to 15thNight
53%5%10%19%11%
1980
16th to endNight
66%410%12%5%
2126
November1st to 15thNight
57%5%13%15%8%
2424
16th to endNight
70%49%10%3
2520
December1st to 15thNight
75%5%6%9%3
2520
16th to endNight
76%36%7%5%
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
31%28%28%6%5%
60
16th to endDay
32%17%32%11%5%
86
February1st to 15thDay
26%34%32%6%
90
16th to endDay
40%19%29%9%1
105
March1st to 15thDay
25%20%32%17%2
270
16th to endDay
19%21%32%16%8%1
288
April1st to 15thDay
26%19%32%15%5%
270
16th to endDay
25%21%26%14%9%2
270
May1st to 15thDay
33%10%23%20%8%3
288
16th to endDay
21%18%30%21%6%2
331
June1st to 15thDay
25%13%32%20%6%
330
16th to endDay
20%12%34%22%8%1
495
July1st to 15thDay
16%11%34%27%8%2
406
16th to endDay
15%10%33%27%10%3
326
August1st to 15thDay
17%5%31%29%7%8%
313
16th to endDay
19%8%28%27%10%6%
332
September1st to 15thDay
23%9%27%21%12%7%
299
16th to endDay
21%9%31%21%11%5%
254
October1st to 15thDay
28%14%29%17%8%1
255
16th to endDay
43%13%26%14%2
269
November1st to 15thDay
24%18%37%14%4
85
16th to endDay
40%15%33%11%
60
December1st to 15thDay
35%21%30%13%
60
16th to endDay
28%43%23%4
64
January1st to 15thNight
26%23%32%14%2
720
16th to endNight
21%17%35%18%5%1
768
February1st to 15thNight
19%21%39%15%4
704
16th to endNight
21%19%37%18%3
631
March1st to 15thNight
24%23%32%17%2
720
16th to endNight
17%17%32%21%8%1
768
April1st to 15thNight
26%16%32%19%4
718
16th to endNight
24%13%29%21%10%
573
May1st to 15thNight
22%9%29%27%10%
411
16th to endNight
17%10%36%25%9%
375
June1st to 15thNight
20%11%31%29%6%
360
16th to endNight
16%7%30%36%8%
360
July1st to 15thNight
12%5%33%33%14%
340
16th to endNight
11%5%32%35%13%1
385
August1st to 15thNight
13%5%24%33%19%3
539
16th to endNight
12%6%31%30%17%1
633
September1st to 15thNight
18%8%29%25%14%2
707
16th to endNight
21%8%26%27%13%2
657
October1st to 15thNight
28%13%27%21%8%
660
16th to endNight
33%18%27%15%5%
704
November1st to 15thNight
25%20%25%19%7%
700
16th to endNight
32%16%28%17%4
720
December1st to 15thNight
31%21%32%11%2
720
16th to endNight
32%18%31%13%21
768
Page generated at 2017-09-13 07:39:23. Version ac04

Copyright 2017 A. Danko


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