Elbow Falls
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Elbow Falls clear sky chart from 2005-11-05 to 2017-08-12.

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
29%
15008
14%
46445
6%
14976
38%
14976
18%
29999

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%
900
13%
2685
3%
895
24%
895
13%
1803
January16th to endNight
18%
786
19%
2706
7%
786
32%
786
15%
1681
February1st to 15thNight
23%
699
15%
2432
7%
696
36%
696
16%
1510
February16th to endNight
28%
632
16%
1950
8%
632
39%
632
18%
1303
March1st to 15thNight
22%
720
17%
2134
5%
720
35%
720
17%
1373
March16th to endNight
28%
768
14%
2065
3%
768
36%
768
18%
1465
April1st to 15thNight
29%
647
10%
1727
3%
647
33%
647
15%
1249
April16th to endNight
32%
540
11%
1620
7%
540
36%
540
16%
1129
May1st to 15thNight
40%
401
9%
1430
10%
401
44%
401
18%
934
May16th to endNight
38%
374
5%
1309
3%
374
40%
374
14%
964
June1st to 15thNight
40%
360
1%
1260
0%
360
40%
360
15%
896
June16th to endNight
44%
360
1%
1260
0%
360
44%
360
19%
806
July1st to 15thNight
52%
340
3%
1190
0%
340
53%
340
24%
715
July16th to endNight
55%
376
9%
1313
9%
354
59%
354
29%
712
August1st to 15thNight
62%
374
15%
1422
19%
372
67%
372
27%
808
August16th to endNight
50%
525
18%
1575
14%
525
53%
525
35%
859
September1st to 15thNight
49%
633
18%
1670
10%
633
53%
633
33%
1033
September16th to endNight
39%
656
20%
1815
9%
656
48%
656
27%
1117
October1st to 15thNight
31%
660
16%
1944
7%
660
41%
660
18%
1321
October16th to endNight
26%
704
21%
2288
7%
704
43%
704
19%
1416
November1st to 15thNight
13%
793
18%
2370
4%
793
28%
793
15%
1470
November16th to endNight
17%
900
14%
2700
3%
900
28%
900
15%
1756
December1st to 15thNight
20%
900
16%
2700
6%
900
29%
900
15%
1800
December16th to endNight
18%
960
18%
2880
3%
960
33%
960
16%
1879

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
9%9%47%6%35%5%6%8%32%
47560
Night
5%7%37%5%35%5%6%9%39%
46598
Cloud CoverDay
9%9%47%6%35%5%6%8%33%
47561
Night
5%7%36%5%35%5%6%8%40%
46601
TransparencyDay
46%9%15%19%8%1
47218
Night
38%9%17%22%10%1
46445
SeeingDay
17%21%29%20%8%2
5840
Night
9%23%30%22%11%2
15015

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
15%38%6%36%6%9%11%38%
1253
16th to endDay
6%5%8%6%47%5%6%11%36%
1528
February1st to 15thDay
15%48%7%5%7%6%8%8%35%
1431
16th to endDay
16%6%13%9%46%6%7%8%29%
1521
March1st to 15thDay
6%48%7%35%6%8%11%35%
1825
16th to endDay
412%7%11%8%45%6%6%9%22%
2156
April1st to 15thDay
7%15%8%7%5%45%5%7%8%23%
2221
16th to endDay
8%19%6%7%6%2445%7%26%
2340
May1st to 15thDay
9%15%47%5%345%6%8%29%
2519
16th to endDay
23%11%36%6%35%5%5%7%20%
2802
June1st to 15thDay
22%11%47%7%35%45%7%21%
2700
16th to endDay
17%7%37%7%46%5%5%6%27%
2700
July1st to 15thDay
12%6%36%6%47%6%6%7%32%
2700
16th to endDay
8%5%35%5%45%6%6%7%40%
2763
August1st to 15thDay
13%7%37%5%46%6%5%7%32%
2445
16th to endDay
11%5%25%5%345%6%7%41%
2275
September1st to 15thDay
14%7%25%423445%45%
1958
16th to endDay
10%5%24435%5%6%7%43%
1815
October1st to 15thDay
9%11%37%6%3446%8%31%
1684
16th to endDay
49%37%435%7%8%8%36%
1584
November1st to 15thDay
26%46%6%35%47%10%41%
1476
16th to endDay
26%38%6%25%45%9%44%
1260
December1st to 15thDay
16%310%7%37%6%7%10%34%
1260
16th to endDay
6%49%6%36%5%7%10%38%
1344
January1st to 15thNight
16%48%7%46%6%8%11%34%
2685
16th to endNight
16%48%7%45%5%6%10%39%
2706
February1st to 15thNight
15%37%7%35%8%7%10%38%
2421
16th to endNight
7%49%7%46%7%6%9%37%
1950
March1st to 15thNight
5%46%6%35%6%8%11%41%
2134
16th to endNight
19%48%7%445%7%9%34%
2062
April1st to 15thNight
6%11%7%8%425%5%7%9%31%
1727
16th to endNight
412%5%8%5%4446%7%35%
1620
May1st to 15thNight
6%11%47%6%25%36%7%36%
1429
16th to endNight
20%11%26%5%3447%6%27%
1309
June1st to 15thNight
16%9%47%5%24447%32%
1260
16th to endNight
13%5%245%36%6%5%7%40%
1260
July1st to 15thNight
8%4146%245%47%48%
1260
16th to endNight
6%3234245%7%9%50%
1403
August1st to 15thNight
9%5%243145%6%8%47%
1430
16th to endNight
10%31321336%9%52%
1575
September1st to 15thNight
10%7%1331335%6%51%
1670
16th to endNight
10%41433446%7%49%
1815
October1st to 15thNight
8%10%46%5%26%45%6%37%
1944
16th to endNight
47%27%5%345%7%10%40%
2288
November1st to 15thNight
16%35%445%5%7%9%44%
2370
16th to endNight
17%5%7%6%35%6%7%10%39%
2700
December1st to 15thNight
15%5%9%7%46%5%7%10%37%
2700
16th to endNight
5%410%6%46%5%8%8%37%
2880

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
15%47%435%6%8%11%40%
1253
16th to endDay
6%5%8%6%46%5%6%10%37%
1528
February1st to 15thDay
15%5%7%8%46%6%8%8%36%
1431
16th to endDay
16%6%13%8%37%6%6%9%30%
1521
March1st to 15thDay
7%48%6%36%6%7%11%37%
1825
16th to endDay
414%6%11%7%36%6%7%8%24%
2157
April1st to 15thDay
8%16%6%8%5%346%6%8%24%
2221
16th to endDay
10%20%5%8%5%2435%6%27%
2340
May1st to 15thDay
9%16%47%5%3446%8%29%
2519
16th to endDay
24%11%36%5%35%46%7%20%
2802
June1st to 15thDay
22%10%47%6%35%45%6%21%
2700
16th to endDay
17%6%46%6%46%6%6%7%28%
2700
July1st to 15thDay
12%6%36%6%47%5%6%7%33%
2700
16th to endDay
7%426%5%36%7%7%7%41%
2763
August1st to 15thDay
12%6%36%6%46%6%6%7%33%
2445
16th to endDay
11%5%245%335%6%7%43%
2275
September1st to 15thDay
14%6%15%5%23345%46%
1958
16th to endDay
10%6%13425%5%6%8%44%
1815
October1st to 15thDay
10%11%45%6%345%5%8%33%
1684
16th to endDay
5%8%46%5%35%6%8%9%36%
1584
November1st to 15thDay
27%47%5%345%8%10%41%
1476
16th to endDay
27%37%6%25%46%10%43%
1260
December1st to 15thDay
16%49%7%36%7%7%9%35%
1260
16th to endDay
7%49%6%345%6%9%40%
1344
January1st to 15thNight
6%48%7%36%6%7%9%37%
2685
16th to endNight
15%47%8%35%5%6%9%40%
2706
February1st to 15thNight
16%36%7%35%6%8%9%39%
2421
16th to endNight
18%49%6%46%6%6%8%37%
1950
March1st to 15thNight
5%47%5%446%8%10%41%
2134
16th to endNight
29%48%8%445%6%9%36%
2065
April1st to 15thNight
6%13%6%7%4345%7%9%31%
1727
16th to endNight
5%13%5%6%6%2446%7%35%
1620
May1st to 15thNight
6%11%5%6%5%35%46%7%37%
1429
16th to endNight
20%11%26%4245%6%7%28%
1309
June1st to 15thNight
17%8%36%5%345%46%33%
1260
16th to endNight
11%6%24435%6%6%7%40%
1260
July1st to 15thNight
9%5%145%3446%7%48%
1260
16th to endNight
6%3234235%7%10%50%
1403
August1st to 15thNight
10%5%233235%6%8%47%
1430
16th to endNight
9%4222347%8%53%
1575
September1st to 15thNight
11%7%13322346%51%
1670
16th to endNight
10%4143345%6%7%49%
1815
October1st to 15thNight
8%10%46%5%35%45%7%38%
1944
16th to endNight
47%27%5%336%6%9%42%
2288
November1st to 15thNight
16%45%5%35%47%9%45%
2370
16th to endNight
26%5%6%5%35%5%6%9%40%
2700
December1st to 15thNight
17%5%8%7%37%5%6%10%37%
2700
16th to endNight
5%410%6%46%6%8%8%38%
2880

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%13%20%23%6%2
1253
16th to endDay
39%9%16%20%10%3
1528
February1st to 15thDay
39%8%17%23%8%2
1431
16th to endDay
47%9%14%19%8%
1521
March1st to 15thDay
38%10%23%20%7%
1825
16th to endDay
55%9%16%14%4
2157
April1st to 15thDay
54%9%16%13%6%
2221
16th to endDay
56%7%14%15%41
2340
May1st to 15thDay
51%7%16%17%6%
2519
16th to endDay
61%7%12%13%4
2807
June1st to 15thDay
62%8%10%11%5%
2700
16th to endDay
52%9%13%16%6%1
2700
July1st to 15thDay
47%9%14%17%9%1
2541
16th to endDay
38%9%12%24%12%1
2591
August1st to 15thDay
46%11%14%20%6%1
2428
16th to endDay
36%7%15%29%8%1
2275
September1st to 15thDay
40%414%24%14%1
1958
16th to endDay
36%7%15%27%10%1
1815
October1st to 15thDay
47%8%14%18%10%
1684
16th to endDay
39%11%17%22%8%
1584
November1st to 15thDay
35%9%21%22%9%1
1476
16th to endDay
36%8%22%20%8%2
1260
December1st to 15thDay
40%10%21%18%8%1
1260
16th to endDay
37%9%16%23%11%1
1344
January1st to 15thNight
39%11%21%18%6%2
2685
16th to endNight
38%8%16%20%12%4
2706
February1st to 15thNight
37%8%17%21%11%2
2432
16th to endNight
41%8%12%20%14%1
1950
March1st to 15thNight
33%11%23%22%9%
2134
16th to endNight
43%10%16%22%7%
2065
April1st to 15thNight
47%8%17%17%8%
1727
16th to endNight
46%8%16%20%5%1
1620
May1st to 15thNight
44%7%17%23%7%
1430
16th to endNight
53%9%14%17%5%
1309
June1st to 15thNight
50%8%13%18%8%
1260
16th to endNight
39%9%15%24%8%1
1260
July1st to 15thNight
35%8%15%28%10%1
1190
16th to endNight
26%10%17%29%14%
1313
August1st to 15thNight
32%8%18%30%9%1
1422
16th to endNight
26%6%19%34%12%1
1575
September1st to 15thNight
33%5%16%26%16%1
1670
16th to endNight
32%7%17%27%13%2
1815
October1st to 15thNight
44%7%15%21%10%
1944
16th to endNight
35%9%17%27%9%
2288
November1st to 15thNight
32%10%18%24%11%1
2370
16th to endNight
37%9%21%18%9%3
2700
December1st to 15thNight
40%9%19%20%8%1
2700
16th to endNight
39%8%17%22%11%1
2880

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
36%40%31%10%8%
60
16th to endDay
31%35%14%12%6%
64
February1st to 15thDay
339%40%10%41
66
16th to endDay
7%23%33%25%9%
180
March1st to 15thDay
6%41%40%10%1
270
16th to endDay
13%35%32%16%2
288
April1st to 15thDay
16%31%34%14%2
269
16th to endDay
27%27%22%15%42
270
May1st to 15thDay
21%18%28%21%7%1
339
16th to endDay
30%11%18%21%13%4
517
June1st to 15thDay
26%17%23%19%11%2
495
16th to endDay
17%19%28%22%9%3
495
July1st to 15thDay
18%10%28%23%15%3
475
16th to endDay
12%17%34%21%10%2
432
August1st to 15thDay
17%12%30%29%8%2
300
16th to endDay
16%22%34%19%5%1
268
September1st to 15thDay
24%19%26%21%5%2
255
16th to endDay
17%30%28%17%5%
255
October1st to 15thDay
17%23%31%20%5%
173
16th to endDay
9%16%34%26%11%2
96
November1st to 15thDay
8%41%32%12%4
89
16th to endDay
10%25%28%10%10%16%
60
December1st to 15thDay
130%28%21%11%6%
60
16th to endDay
9%25%37%17%9%1
64
January1st to 15thNight
8%33%39%14%2
900
16th to endNight
5%35%33%18%5%1
786
February1st to 15thNight
432%30%18%11%2
704
16th to endNight
5%18%39%24%10%1
632
March1st to 15thNight
5%30%37%19%6%1
720
16th to endNight
7%20%32%27%9%2
768
April1st to 15thNight
12%22%26%28%8%1
647
16th to endNight
14%15%28%26%13%1
540
May1st to 15thNight
13%10%26%28%18%2
402
16th to endNight
26%9%18%20%23%2
375
June1st to 15thNight
21%10%19%29%16%2
360
16th to endNight
16%12%21%28%20%1
360
July1st to 15thNight
15%6%17%34%22%3
340
16th to endNight
7%8%22%36%22%2
376
August1st to 15thNight
14%412%31%32%5%
374
16th to endNight
12%12%21%31%20%2
525
September1st to 15thNight
16%10%18%25%18%10%
633
16th to endNight
12%18%24%25%13%5%
656
October1st to 15thNight
14%20%25%26%10%2
660
16th to endNight
8%24%33%24%5%2
704
November1st to 15thNight
7%36%38%11%32
793
16th to endNight
6%32%39%15%41
900
December1st to 15thNight
5%32%35%17%8%1
900
16th to endNight
432%36%17%7%1
960
Page generated at 2017-08-13 12:16:29. Version ac04

Copyright 2017 A. Danko


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