AllSky Camera - 108 Mile Ranch
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the AllSky Camera - 108 Mile Ranch clear sky chart from 2005-11-05 to 2018-01-12.

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
37%
15320
9%
48327
7%
15292
40%
15292
16%
35207

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
25%
807
5%
2855
4%
804
27%
804
8%
2352
January16th to endNight
32%
785
8%
2789
7%
785
35%
785
11%
2099
February1st to 15thNight
28%
698
7%
2370
6%
697
31%
697
12%
1820
February16th to endNight
41%
632
13%
2026
11%
632
45%
632
20%
1380
March1st to 15thNight
28%
720
9%
2120
5%
720
33%
720
14%
1595
March16th to endNight
36%
768
10%
2032
5%
768
38%
768
18%
1526
April1st to 15thNight
37%
719
9%
1799
4%
719
40%
719
19%
1369
April16th to endNight
37%
438
12%
1518
10%
438
42%
438
14%
1108
May1st to 15thNight
39%
359
9%
1440
12%
359
43%
359
14%
990
May16th to endNight
41%
374
4%
1382
2%
374
42%
374
14%
1002
June1st to 15thNight
41%
360
0%
1080
0%
360
41%
360
14%
819
June16th to endNight
41%
360
0%
1080
0%
360
41%
360
17%
796
July1st to 15thNight
54%
340
1%
1126
0%
340
54%
340
23%
721
July16th to endNight
57%
376
7%
1299
8%
354
60%
354
25%
768
August1st to 15thNight
68%
360
14%
1432
22%
358
70%
358
27%
767
August16th to endNight
59%
589
17%
1735
15%
589
61%
589
30%
1039
September1st to 15thNight
59%
720
18%
1800
10%
720
60%
720
35%
1150
September16th to endNight
47%
716
18%
1960
11%
716
51%
716
26%
1315
October1st to 15thNight
43%
720
12%
2160
10%
720
45%
720
22%
1455
October16th to endNight
30%
768
11%
2468
7%
768
36%
768
15%
1777
November1st to 15thNight
26%
760
8%
2660
5%
760
31%
760
10%
2034
November16th to endNight
28%
856
8%
2806
5%
856
32%
856
11%
2213
December1st to 15thNight
32%
1007
7%
3062
5%
1007
34%
1007
12%
2421
December16th to endNight
24%
1088
7%
3328
4%
1088
27%
1088
10%
2691

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
10%10%48%7%45%5%6%7%30%
49039
Night
9%11%48%7%46%5%6%7%28%
48476
TransparencyDay
52%5%15%18%6%
48692
Night
53%6%15%17%6%
48327
SeeingDay
16%13%24%25%15%3
6820
Night
17%10%24%28%16%2
15329

By Month

Percentage Cloud Cover NW (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
10%15%6%10%8%46%7%7%7%14%
1330
16th to endDay
8%13%7%10%9%45%6%45%22%
1434
February1st to 15thDay
10%17%6%9%6%445%45%24%
1492
16th to endDay
6%11%6%10%7%36%6%6%7%27%
1448
March1st to 15thDay
6%14%6%10%10%5%6%5%5%7%20%
1839
16th to endDay
5%11%6%10%10%45%6%6%8%24%
2192
April1st to 15thDay
9%13%7%8%8%37%5%6%6%21%
2149
16th to endDay
9%12%5%9%8%47%6%6%7%20%
2439
May1st to 15thDay
10%11%38%6%45%5%6%7%30%
2511
16th to endDay
14%9%48%8%46%6%6%7%23%
2726
June1st to 15thDay
18%8%37%7%36%6%5%6%25%
2880
16th to endDay
12%8%48%7%46%5%6%7%27%
2880
July1st to 15thDay
8%5%26%5%36%5%6%7%41%
2763
16th to endDay
8%5%14435%46%7%47%
2781
August1st to 15thDay
6%425%5%345%6%8%47%
2520
16th to endDay
9%425%5%45%5%6%8%40%
2464
September1st to 15thDay
9%5%25%5%2335%7%48%
2160
16th to endDay
14%8%35%5%35%5%47%35%
1998
October1st to 15thDay
11%10%36%5%245%5%6%36%
1800
16th to endDay
16%11%37%5%35%45%5%29%
1753
November1st to 15thDay
13%14%5%9%6%36%6%5%6%21%
1528
16th to endDay
9%13%7%10%8%47%5%6%7%18%
1469
December1st to 15thDay
9%12%6%9%7%5%6%7%6%7%20%
1228
16th to endDay
7%16%6%10%7%36%5%6%7%20%
1255
January1st to 15thNight
10%16%6%13%9%46%5%6%5%15%
2855
16th to endNight
9%12%6%9%8%46%6%6%8%21%
2789
February1st to 15thNight
10%15%7%10%7%4445%6%22%
2358
16th to endNight
6%10%5%7%8%46%46%7%33%
2026
March1st to 15thNight
6%15%6%9%7%46%6%5%7%24%
2120
16th to endNight
5%11%47%8%48%7%6%8%26%
2028
April1st to 15thNight
6%12%6%8%8%36%6%5%7%29%
1799
16th to endNight
8%10%49%8%5%7%5%5%8%24%
1518
May1st to 15thNight
10%11%5%8%7%35%5%5%6%30%
1439
16th to endNight
14%8%5%7%8%47%7%7%8%22%
1382
June1st to 15thNight
18%8%46%6%36%5%7%7%24%
1080
16th to endNight
12%7%37%9%5%7%5%5%6%28%
1080
July1st to 15thNight
7%5%36%6%35%6%7%9%38%
1195
16th to endNight
8%435%5%36%7%7%8%40%
1388
August1st to 15thNight
5%425%6%346%6%7%48%
1440
16th to endNight
7%6%145%46%5%7%9%41%
1735
September1st to 15thNight
8%326%5%2445%6%49%
1800
16th to endNight
12%7%25%435%5%6%7%40%
1960
October1st to 15thNight
9%9%47%6%35%447%37%
2160
16th to endNight
14%9%37%7%35%5%6%6%29%
2468
November1st to 15thNight
13%13%49%7%45%5%6%7%22%
2660
16th to endNight
9%15%5%9%9%46%45%6%22%
2806
December1st to 15thNight
10%14%6%9%9%36%5%5%6%22%
3062
16th to endNight
7%16%6%11%9%5%6%5%5%6%19%
3328

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
64%8%16%6%2
1330
16th to endDay
62%5%16%11%3
1434
February1st to 15thDay
62%415%11%4
1492
16th to endDay
53%6%16%15%7%
1448
March1st to 15thDay
61%5%14%12%5%
1839
16th to endDay
57%5%16%16%3
2192
April1st to 15thDay
61%5%11%14%6%
2149
16th to endDay
60%6%12%14%5%
2439
May1st to 15thDay
53%412%17%11%
2511
16th to endDay
58%5%14%17%4
2730
June1st to 15thDay
58%5%11%15%7%1
2880
16th to endDay
53%5%16%17%6%
2880
July1st to 15thDay
40%5%14%23%13%2
2603
16th to endDay
33%6%17%30%10%
2607
August1st to 15thDay
33%5%18%30%10%
2503
16th to endDay
38%6%20%24%8%1
2464
September1st to 15thDay
35%5%18%28%11%1
2160
16th to endDay
48%5%14%21%8%1
1998
October1st to 15thDay
47%421%21%4
1800
16th to endDay
55%5%19%16%2
1753
November1st to 15thDay
61%6%13%13%4
1528
16th to endDay
63%7%11%13%3
1469
December1st to 15thDay
59%10%15%12%1
1228
16th to endDay
61%6%15%11%3
1255
January1st to 15thNight
69%5%12%9%3
2855
16th to endNight
57%8%16%13%21
2789
February1st to 15thNight
61%5%13%13%5%
2370
16th to endNight
48%419%18%8%
2026
March1st to 15thNight
56%5%15%16%5%
2120
16th to endNight
52%6%18%17%3
2032
April1st to 15thNight
53%6%15%19%5%
1799
16th to endNight
56%5%13%18%6%
1518
May1st to 15thNight
53%411%18%11%
1440
16th to endNight
55%6%18%14%4
1382
June1st to 15thNight
55%8%9%19%6%
1080
16th to endNight
55%5%16%16%6%1
1080
July1st to 15thNight
40%8%14%19%14%2
1126
16th to endNight
38%6%17%26%11%
1299
August1st to 15thNight
32%6%17%30%12%1
1432
16th to endNight
36%420%26%8%2
1735
September1st to 15thNight
33%6%14%29%13%2
1800
16th to endNight
42%5%15%21%11%2
1960
October1st to 15thNight
46%416%25%6%
2160
16th to endNight
53%6%18%19%2
2468
November1st to 15thNight
59%7%14%12%5%
2660
16th to endNight
62%6%13%12%5%
2806
December1st to 15thNight
61%6%15%12%3
3062
16th to endNight
65%6%13%11%3
3328

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
17%7%24%23%20%7%
82
16th to endDay
18%20%32%15%10%1
64
February1st to 15thDay
16%17%31%26%7%1
152
16th to endDay
12%16%28%24%14%3
216
March1st to 15thDay
23%26%26%17%5%1
270
16th to endDay
18%25%32%18%31
288
April1st to 15thDay
19%19%25%23%11%1
269
16th to endDay
20%20%26%22%7%1
270
May1st to 15thDay
18%17%26%20%13%3
288
16th to endDay
19%11%19%25%18%4
441
June1st to 15thDay
20%10%24%28%14%2
675
16th to endDay
16%10%23%28%18%3
675
July1st to 15thDay
11%7%25%29%21%3
537
16th to endDay
12%6%23%32%19%4
450
August1st to 15thDay
8%5%17%33%25%9%
315
16th to endDay
12%8%25%29%17%5%
332
September1st to 15thDay
10%14%26%25%15%6%
315
16th to endDay
20%11%23%23%16%3
315
October1st to 15thDay
20%18%23%18%14%5%
315
16th to endDay
23%16%21%18%17%2
185
November1st to 15thDay
24%27%24%12%8%2
90
16th to endDay
15%21%25%15%16%5%
90
December1st to 15thDay
10%10%18%31%16%13%
90
16th to endDay
12%8%28%29%18%3
96
January1st to 15thNight
22%10%25%26%12%2
808
16th to endNight
17%12%27%28%11%1
785
February1st to 15thNight
20%9%28%26%12%1
704
16th to endNight
12%8%25%36%14%2
632
March1st to 15thNight
18%15%29%23%10%2
720
16th to endNight
12%15%28%25%16%1
768
April1st to 15thNight
13%10%26%27%17%3
719
16th to endNight
13%10%31%27%14%2
438
May1st to 15thNight
16%9%25%29%17%2
360
16th to endNight
18%8%19%28%21%4
375
June1st to 15thNight
20%6%20%32%18%1
360
16th to endNight
15%6%24%31%20%2
360
July1st to 15thNight
9%5%21%33%27%3
340
16th to endNight
9%6%18%30%31%4
376
August1st to 15thNight
6%310%33%37%7%
360
16th to endNight
11%417%32%30%4
589
September1st to 15thNight
11%5%17%31%28%6%
720
16th to endNight
18%8%20%28%20%3
716
October1st to 15thNight
18%9%21%28%18%2
720
16th to endNight
21%12%27%23%13%2
768
November1st to 15thNight
24%17%24%23%8%2
760
16th to endNight
22%14%25%25%9%2
856
December1st to 15thNight
19%11%22%30%13%2
1007
16th to endNight
17%15%30%26%9%
1088
Page generated at 2018-01-12 19:01:30. Version ac04

Copyright 2018 A. Danko


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