Lake Buffum
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lake Buffum clear sky chart from 2005-11-05 to 2017-04-24.

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
60%
15512
20%
45578
16%
15471
64%
15471
29%
28984

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
50%
718
19%
2327
14%
716
58%
716
25%
1452
January16th to endNight
47%
768
25%
2436
18%
768
56%
768
30%
1453
February1st to 15thNight
47%
701
23%
2103
16%
698
55%
698
33%
1254
February16th to endNight
46%
631
26%
1821
14%
631
57%
631
35%
1068
March1st to 15thNight
50%
720
29%
1980
18%
720
60%
720
40%
1144
March16th to endNight
57%
768
26%
2112
20%
768
62%
768
41%
1206
April1st to 15thNight
62%
718
23%
1976
18%
718
66%
718
42%
1114
April16th to endNight
58%
696
25%
1788
15%
696
64%
696
42%
1052
May1st to 15thNight
70%
546
27%
1536
20%
546
74%
546
41%
862
May16th to endNight
75%
513
20%
1539
16%
513
76%
513
33%
959
June1st to 15thNight
69%
495
10%
1485
9%
495
70%
495
22%
1065
June16th to endNight
73%
495
7%
1485
6%
495
73%
495
20%
1100
July1st to 15thNight
69%
465
6%
1395
6%
465
69%
465
17%
1095
July16th to endNight
74%
522
7%
1469
7%
489
75%
489
21%
1095
August1st to 15thNight
81%
494
5%
1474
6%
491
81%
491
24%
1036
August16th to endNight
64%
673
6%
1896
5%
673
64%
673
18%
1414
September1st to 15thNight
64%
660
6%
1815
6%
660
64%
660
17%
1369
September16th to endNight
59%
657
10%
1815
10%
657
60%
657
17%
1362
October1st to 15thNight
67%
660
24%
1875
24%
660
69%
660
31%
1189
October16th to endNight
58%
704
27%
2112
24%
704
64%
704
31%
1285
November1st to 15thNight
61%
700
31%
2101
27%
700
68%
700
38%
1186
November16th to endNight
53%
720
29%
2202
23%
720
62%
720
32%
1336
December1st to 15thNight
54%
720
24%
2340
21%
720
59%
720
28%
1406
December16th to endNight
57%
768
22%
2496
21%
768
62%
768
30%
1482

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
8%5%36%7%46%6%6%8%36%
46012
Night
7%5%25%5%35%5%6%9%43%
45786
TransparencyDay
43%9%13%15%12%5%
45713
Night
35%9%16%19%14%5%
45589
SeeingDay
8%213%21%25%29%
5253
Night
9%218%33%27%9%
15520

By Month

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
11%7%26%5%25%5%6%8%38%
1611
16th to endDay
9%6%235%3445%7%47%
1785
February1st to 15thDay
11%5%245%3345%7%45%
1750
16th to endDay
8%5%25%5%2445%8%47%
1652
March1st to 15thDay
5%2245%36%5%5%8%51%
1980
16th to endDay
7%4145%36%5%47%48%
2111
April1st to 15thDay
5%315%6%46%6%7%8%43%
1972
16th to endDay
6%425%6%37%6%49%44%
2032
May1st to 15thDay
5%3145%36%5%6%8%47%
2091
16th to endDay
6%6%27%8%5%8%6%7%8%32%
2223
June1st to 15thDay
12%7%37%7%46%7%7%9%24%
2145
16th to endDay
9%7%48%8%48%7%7%8%23%
2145
July1st to 15thDay
9%8%410%9%5%8%7%6%8%19%
2145
16th to endDay
8%6%49%10%5%8%8%7%9%20%
2283
August1st to 15thDay
6%7%39%9%5%8%8%8%10%22%
2142
16th to endDay
10%7%49%8%5%8%8%7%9%20%
1941
September1st to 15thDay
9%7%39%8%5%7%8%7%8%22%
1815
16th to endDay
10%7%48%10%6%8%6%7%8%20%
1815
October1st to 15thDay
8%5%27%7%45%6%7%8%37%
1754
16th to endDay
8%5%25%5%45%447%44%
1760
November1st to 15thDay
5%4146%35%45%8%49%
1757
16th to endDay
7%5%25%7%35%46%7%44%
1755
December1st to 15thDay
10%5%37%5%35%5%5%8%40%
1620
16th to endDay
7%5%35%435%5%5%8%45%
1728
January1st to 15thNight
9%6%25%5%345%5%9%41%
2327
16th to endNight
10%5%244245%7%8%45%
2436
February1st to 15thNight
11%5%1432435%7%48%
2103
16th to endNight
7%5%144245%5%8%49%
1821
March1st to 15thNight
4413435%45%7%54%
1980
16th to endNight
6%32442345%9%54%
2112
April1st to 15thNight
432242446%9%55%
1976
16th to endNight
6%42342445%7%54%
1788
May1st to 15thNight
4313325%5%48%57%
1536
16th to endNight
7%3234346%7%10%46%
1538
June1st to 15thNight
8%5%37%7%45%7%7%11%31%
1485
16th to endNight
6%436%8%6%7%6%8%10%32%
1485
July1st to 15thNight
8%7%28%6%47%7%8%10%28%
1485
16th to endNight
4446%7%48%7%10%12%28%
1577
August1st to 15thNight
5%435%5%36%7%10%12%35%
1485
16th to endNight
9%5%28%6%47%6%9%11%29%
1896
September1st to 15thNight
6%7%36%7%47%5%8%12%29%
1815
16th to endNight
11%7%28%7%5%5%6%7%10%27%
1815
October1st to 15thNight
7%5%25%5%35%46%7%46%
1875
16th to endNight
9%6%3442435%8%47%
2112
November1st to 15thNight
7%32442445%7%53%
2101
16th to endNight
8%425%5%25%45%8%46%
2202
December1st to 15thNight
9%435%5%245%6%8%44%
2340
16th to endNight
6%424435%5%6%9%45%
2496

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
41%6%9%19%18%5%
1612
16th to endDay
35%5%7%18%23%9%
1785
February1st to 15thDay
37%47%14%21%13%
1752
16th to endDay
35%6%10%16%21%10%
1652
March1st to 15thDay
30%6%11%22%20%8%
1980
16th to endDay
33%6%11%19%20%8%
2112
April1st to 15thDay
34%8%12%19%17%6%
1972
16th to endDay
35%7%11%16%20%8%
2032
May1st to 15thDay
32%8%14%19%17%7%
2091
16th to endDay
44%11%13%17%12%1
2227
June1st to 15thDay
52%10%17%15%3
2145
16th to endDay
53%14%17%11%2
2145
July1st to 15thDay
59%14%17%6%1
2006
16th to endDay
55%14%18%9%1
2128
August1st to 15thDay
52%16%24%6%
2129
16th to endDay
56%15%19%7%
1941
September1st to 15thDay
54%15%17%9%2
1815
16th to endDay
56%11%16%8%41
1815
October1st to 15thDay
41%9%12%14%14%7%
1754
16th to endDay
38%6%9%13%21%11%
1760
November1st to 15thDay
31%5%9%22%21%9%
1757
16th to endDay
38%5%9%17%15%12%
1755
December1st to 15thDay
40%7%12%16%17%5%
1620
16th to endDay
35%6%14%19%17%7%
1728
January1st to 15thNight
38%6%12%19%15%6%
2327
16th to endNight
35%5%11%21%18%8%
2436
February1st to 15thNight
34%49%16%21%12%
2112
16th to endNight
30%7%14%18%21%7%
1821
March1st to 15thNight
27%6%10%27%20%7%
1980
16th to endNight
27%5%13%24%20%8%
2112
April1st to 15thNight
24%7%16%24%20%6%
1976
16th to endNight
26%6%15%22%22%6%
1788
May1st to 15thNight
24%8%17%25%18%5%
1537
16th to endNight
30%11%18%24%15%
1540
June1st to 15thNight
43%12%21%17%4
1485
16th to endNight
43%15%21%15%3
1485
July1st to 15thNight
47%17%24%8%2
1395
16th to endNight
42%16%28%12%
1469
August1st to 15thNight
33%19%36%10%
1474
16th to endNight
45%16%27%10%1
1896
September1st to 15thNight
45%16%22%13%2
1815
16th to endNight
50%12%17%14%31
1815
October1st to 15thNight
35%7%12%20%17%6%
1875
16th to endNight
35%6%9%17%22%9%
2112
November1st to 15thNight
29%5%11%22%22%9%
2101
16th to endNight
34%6%8%20%18%11%
2202
December1st to 15thNight
35%6%13%22%14%6%
2340
16th to endNight
32%7%15%19%15%8%
2496

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
22%8%26%26%8%6%
90
16th to endDay
11%14%33%21%16%2
96
February1st to 15thDay
8%10%25%26%20%8%
90
16th to endDay
11%5%33%33%13%1
153
March1st to 15thDay
5%429%32%24%3
270
16th to endDay
10%419%27%31%6%
288
April1st to 15thDay
4223%31%27%10%
270
16th to endDay
8%211%23%35%18%
243
May1st to 15thDay
6%10%21%34%27%
228
16th to endDay
5%5%19%30%38%
267
June1st to 15thDay
15%5%11%22%43%
255
16th to endDay
6%47%20%61%
255
July1st to 15thDay
6%2318%68%
245
16th to endDay
8%148%20%56%
270
August1st to 15thDay
5%16%11%16%59%
253
16th to endDay
6%15%12%16%57%
268
September1st to 15thDay
10%16%10%21%49%
255
16th to endDay
12%311%31%40%
254
October1st to 15thDay
9%7%30%34%17%
255
16th to endDay
12%118%30%27%10%
272
November1st to 15thDay
8%15%33%29%12%
265
16th to endDay
8%321%34%27%4
225
December1st to 15thDay
13%327%40%15%
90
16th to endDay
6%5%13%33%35%6%
96
January1st to 15thNight
12%5%23%40%16%1
720
16th to endNight
12%6%29%37%14%
768
February1st to 15thNight
13%5%29%39%11%
704
16th to endNight
9%433%40%11%
631
March1st to 15thNight
5%433%42%11%1
720
16th to endNight
7%325%43%19%
768
April1st to 15thNight
5%223%47%19%1
718
16th to endNight
7%323%43%21%
696
May1st to 15thNight
5%114%48%25%3
547
16th to endNight
6%9%37%38%7%
515
June1st to 15thNight
8%5%26%45%13%
495
16th to endNight
6%414%43%30%
495
July1st to 15thNight
9%29%44%33%
465
16th to endNight
419%46%36%
522
August1st to 15thNight
5%17%48%35%
494
16th to endNight
10%5%17%36%28%
673
September1st to 15thNight
10%5%21%38%23%
660
16th to endNight
14%5%25%39%14%
657
October1st to 15thNight
10%10%36%35%5%
660
16th to endNight
12%217%32%30%3
704
November1st to 15thNight
8%221%40%25%3
700
16th to endNight
7%327%41%19%1
720
December1st to 15thNight
9%5%25%37%21%1
720
16th to endNight
8%325%37%24%1
768
Page generated at 2017-04-25 07:48:23. Version ac04

Copyright 2017 A. Danko


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