Little Bow Reservoir
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Little Bow Reservoir clear sky chart from 2005-11-05 to 2017-09-19.

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
39%
15264
14%
46806
9%
15236
45%
15236
22%
31263

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
29%
897
12%
2685
7%
895
34%
895
16%
1993
January16th to endNight
31%
829
16%
2749
10%
829
40%
829
19%
1852
February1st to 15thNight
38%
698
12%
2368
11%
697
42%
697
16%
1649
February16th to endNight
38%
632
12%
1999
9%
632
42%
632
17%
1444
March1st to 15thNight
32%
720
13%
2088
7%
720
40%
720
20%
1484
March16th to endNight
32%
768
10%
2112
2%
768
38%
768
18%
1578
April1st to 15thNight
33%
606
12%
1702
5%
606
38%
606
18%
1249
April16th to endNight
40%
540
14%
1620
10%
540
43%
540
20%
1138
May1st to 15thNight
44%
479
12%
1461
11%
479
47%
479
24%
949
May16th to endNight
42%
375
7%
1309
5%
374
45%
374
16%
916
June1st to 15thNight
41%
360
3%
1260
1%
360
41%
360
19%
827
June16th to endNight
49%
360
3%
1260
1%
360
50%
360
25%
742
July1st to 15thNight
60%
340
4%
1190
2%
340
61%
340
31%
656
July16th to endNight
62%
376
14%
1267
14%
354
68%
354
37%
635
August1st to 15thNight
65%
447
14%
1519
15%
445
68%
445
34%
831
August16th to endNight
61%
573
25%
1719
19%
573
65%
573
44%
904
September1st to 15thNight
52%
633
20%
1812
13%
633
56%
633
36%
1078
September16th to endNight
47%
671
22%
1856
13%
671
55%
671
37%
1112
October1st to 15thNight
39%
660
18%
1936
9%
660
48%
660
23%
1305
October16th to endNight
43%
704
20%
2277
13%
704
52%
704
25%
1425
November1st to 15thNight
28%
836
18%
2411
9%
836
38%
836
23%
1634
November16th to endNight
30%
900
14%
2626
7%
900
37%
900
23%
1784
December1st to 15thNight
33%
900
11%
2700
8%
900
37%
900
16%
1990
December16th to endNight
30%
960
13%
2880
6%
960
36%
960
17%
2088

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%7%36%5%35%5%5%8%38%
48043
Night
8%8%36%5%35%5%6%8%38%
46955
Cloud CoverDay
9%8%36%5%35%5%6%8%38%
48044
Night
8%8%46%5%35%5%6%8%37%
46958
TransparencyDay
41%7%15%23%9%1
47696
Night
42%7%15%21%10%1
46806
SeeingDay
13%7%25%29%19%5%
6028
Night
12%7%31%31%14%2
15274

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%10%48%6%34447%34%
1253
16th to endDay
5%10%39%6%36%5%6%9%31%
1485
February1st to 15thDay
9%11%48%7%36%6%5%7%30%
1494
16th to endDay
6%13%7%9%7%446%6%8%26%
1473
March1st to 15thDay
6%11%48%7%45%5%48%32%
1872
16th to endDay
9%11%6%8%6%45%5%5%8%28%
2111
April1st to 15thDay
11%10%5%7%6%35%5%6%7%30%
2243
16th to endDay
13%9%36%5%36%6%6%6%32%
2340
May1st to 15thDay
12%7%35%5%245%6%7%38%
2487
16th to endDay
20%6%26%435%5%6%7%29%
2802
June1st to 15thDay
16%6%26%5%35%5%6%9%32%
2700
16th to endDay
11%5%25%425%5%6%9%40%
2700
July1st to 15thDay
7%3244245%6%9%50%
2700
16th to endDay
5%21342445%9%56%
2814
August1st to 15thDay
8%3243235%6%10%48%
2431
16th to endDay
9%31322345%8%54%
2483
September1st to 15thDay
12%5%22422346%53%
2146
16th to endDay
11%41332445%8%51%
1849
October1st to 15thDay
14%8%37%5%345%5%7%34%
1694
16th to endDay
7%7%36%6%36%6%6%7%37%
1595
November1st to 15thDay
9%10%36%6%35%5%7%7%33%
1435
16th to endDay
5%12%5%8%5%235%7%9%36%
1332
December1st to 15thDay
7%12%6%11%7%5%5%45%7%25%
1260
16th to endDay
5%11%49%9%37%6%6%8%27%
1344
January1st to 15thNight
7%10%5%9%6%47%5%7%8%27%
2685
16th to endNight
6%11%37%6%35%5%6%7%35%
2749
February1st to 15thNight
8%9%47%7%46%5%5%6%33%
2357
16th to endNight
5%12%6%10%7%45%5%5%7%29%
1999
March1st to 15thNight
6%9%5%7%6%36%5%8%9%30%
2088
16th to endNight
9%11%5%8%6%35%5%6%7%29%
2109
April1st to 15thNight
11%9%47%6%45%45%9%30%
1702
16th to endNight
12%10%45%6%35%5%6%6%34%
1620
May1st to 15thNight
9%8%37%4345%5%7%39%
1460
16th to endNight
18%6%25%5%36%5%6%8%31%
1309
June1st to 15thNight
15%5%36%4345%6%8%35%
1260
16th to endNight
9%324435%6%7%9%41%
1260
July1st to 15thNight
6%315%42435%8%51%
1260
16th to endNight
4212425%5%6%7%56%
1353
August1st to 15thNight
5%3144235%5%9%52%
1527
16th to endNight
6%313223447%59%
1719
September1st to 15thNight
11%5%14323346%53%
1812
16th to endNight
8%4145%2445%8%51%
1856
October1st to 15thNight
12%8%36%5%245%5%7%38%
1936
16th to endNight
8%5%25%6%3447%8%43%
2277
November1st to 15thNight
6%8%47%6%35%5%5%6%40%
2411
16th to endNight
7%10%47%425%46%9%36%
2626
December1st to 15thNight
6%11%410%7%46%5%5%7%31%
2700
16th to endNight
6%13%6%8%6%36%5%6%8%28%
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
9%11%49%6%34447%33%
1253
16th to endDay
5%10%49%6%36%5%6%10%30%
1485
February1st to 15thDay
9%10%47%8%46%5%5%7%29%
1494
16th to endDay
5%13%7%9%7%45%6%5%7%25%
1473
March1st to 15thDay
5%11%48%8%47%5%48%31%
1872
16th to endDay
9%11%5%8%7%35%5%6%8%27%
2112
April1st to 15thDay
11%10%47%6%45%5%6%8%29%
2243
16th to endDay
12%10%35%6%45%6%5%7%32%
2340
May1st to 15thDay
11%7%35%5%345%6%7%38%
2487
16th to endDay
19%7%26%5%26%5%6%7%29%
2802
June1st to 15thDay
15%7%36%5%35%5%6%9%32%
2700
16th to endDay
10%6%25%435%5%6%9%40%
2700
July1st to 15thDay
6%4144345%6%9%50%
2700
16th to endDay
43332346%9%55%
2814
August1st to 15thDay
7%41342446%10%49%
2431
16th to endDay
8%4321436%8%54%
2483
September1st to 15thDay
12%5%13422346%52%
2146
16th to endDay
10%414323348%51%
1849
October1st to 15thDay
13%9%36%6%3446%8%33%
1694
16th to endDay
7%8%36%6%36%6%6%7%37%
1595
November1st to 15thDay
8%11%37%5%46%5%6%8%32%
1435
16th to endDay
5%11%5%8%5%2447%8%35%
1332
December1st to 15thDay
7%12%7%11%8%5%6%36%7%24%
1260
16th to endDay
5%10%5%9%8%47%6%6%9%27%
1344
January1st to 15thNight
6%11%5%8%6%47%6%7%8%26%
2685
16th to endNight
6%11%46%6%35%47%7%34%
2749
February1st to 15thNight
8%9%47%8%46%5%5%6%32%
2357
16th to endNight
5%12%6%9%8%36%5%5%7%29%
1999
March1st to 15thNight
5%9%5%8%6%35%5%8%9%30%
2088
16th to endNight
9%10%5%8%6%46%5%6%8%28%
2112
April1st to 15thNight
11%9%47%6%45%6%5%7%30%
1702
16th to endNight
12%9%35%5%45%5%6%7%34%
1620
May1st to 15thNight
9%8%46%5%25%5%47%39%
1460
16th to endNight
17%6%25%5%36%7%6%7%31%
1309
June1st to 15thNight
13%7%36%4345%7%8%34%
1260
16th to endNight
9%2245%45%6%7%10%41%
1260
July1st to 15thNight
5%32443445%8%51%
1260
16th to endNight
3213335%5%7%8%56%
1353
August1st to 15thNight
5%3235%245%6%8%51%
1527
16th to endNight
6%31232335%8%59%
1719
September1st to 15thNight
10%5%14413346%52%
1812
16th to endNight
8%415%435%45%7%51%
1856
October1st to 15thNight
12%9%25%5%245%5%7%37%
1936
16th to endNight
8%6%246%35%5%6%8%42%
2277
November1st to 15thNight
6%8%47%5%35%5%5%6%40%
2411
16th to endNight
6%10%5%7%43446%8%36%
2626
December1st to 15thNight
5%11%5%10%7%46%45%7%30%
2700
16th to endNight
6%12%6%9%7%35%5%6%8%27%
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
50%7%14%20%5%1
1253
16th to endDay
46%8%15%18%7%3
1485
February1st to 15thDay
52%7%16%16%6%1
1494
16th to endDay
53%9%14%16%5%
1473
March1st to 15thDay
50%8%17%17%6%
1872
16th to endDay
52%8%13%18%5%
2112
April1st to 15thDay
50%8%14%18%7%1
2243
16th to endDay
47%8%14%20%7%1
2340
May1st to 15thDay
40%7%13%25%12%
2487
16th to endDay
50%7%14%19%6%
2807
June1st to 15thDay
46%8%17%18%7%1
2700
16th to endDay
36%8%18%25%9%1
2700
July1st to 15thDay
28%8%18%32%10%1
2541
16th to endDay
23%7%19%28%17%3
2637
August1st to 15thDay
28%8%20%31%10%1
2414
16th to endDay
25%5%15%33%17%2
2483
September1st to 15thDay
32%412%26%16%6%
2146
16th to endDay
31%6%12%32%12%4
1849
October1st to 15thDay
46%7%15%21%7%1
1694
16th to endDay
42%7%16%23%8%1
1595
November1st to 15thDay
45%9%15%20%7%
1435
16th to endDay
43%7%17%21%8%1
1332
December1st to 15thDay
57%7%13%16%4
1260
16th to endDay
51%6%15%18%6%
1344
January1st to 15thNight
51%9%15%16%5%1
2685
16th to endNight
45%7%16%18%10%2
2749
February1st to 15thNight
49%7%13%18%9%1
2368
16th to endNight
50%8%14%18%7%
1999
March1st to 15thNight
45%9%17%20%5%
2088
16th to endNight
50%8%15%17%6%
2112
April1st to 15thNight
50%8%12%19%9%
1702
16th to endNight
47%7%12%21%8%1
1620
May1st to 15thNight
42%6%11%25%12%2
1461
16th to endNight
47%10%15%17%7%1
1309
June1st to 15thNight
43%8%15%21%8%1
1260
16th to endNight
35%7%17%24%13%1
1260
July1st to 15thNight
29%7%16%28%14%2
1190
16th to endNight
22%8%17%27%19%4
1267
August1st to 15thNight
27%8%20%26%13%2
1519
16th to endNight
22%5%13%30%22%5%
1719
September1st to 15thNight
31%5%10%24%20%7%
1812
16th to endNight
30%6%14%27%16%4
1856
October1st to 15thNight
42%8%15%19%11%1
1936
16th to endNight
37%8%16%25%11%
2277
November1st to 15thNight
42%7%15%21%12%
2411
16th to endNight
43%7%20%15%10%2
2626
December1st to 15thNight
52%7%15%18%5%
2700
16th to endNight
50%8%16%19%5%
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
18%116%21%21%20%
60
16th to endDay
12%9%25%26%15%10%
64
February1st to 15thDay
18%10%22%32%12%3
77
16th to endDay
18%333%31%12%
132
March1st to 15thDay
12%12%41%25%7%
270
16th to endDay
12%14%36%26%10%1
288
April1st to 15thDay
12%15%29%29%10%2
269
16th to endDay
20%7%27%28%13%2
270
May1st to 15thDay
13%5%28%29%18%4
387
16th to endDay
22%5%19%25%21%5%
517
June1st to 15thDay
14%9%22%31%18%3
495
16th to endDay
11%427%32%20%4
495
July1st to 15thDay
7%218%36%27%6%
475
16th to endDay
6%326%35%21%5%
483
August1st to 15thDay
7%118%32%29%9%
315
16th to endDay
8%5%21%29%25%9%
332
September1st to 15thDay
18%8%19%26%21%6%
315
16th to endDay
13%10%27%25%14%7%
268
October1st to 15thDay
16%14%23%27%16%1
134
16th to endDay
14%425%31%19%5%
96
November1st to 15thDay
17%17%33%18%11%1
90
16th to endDay
11%431%30%12%9%
72
December1st to 15thDay
8%8%46%18%18%
60
16th to endDay
12%9%26%21%25%4
64
January1st to 15thNight
12%11%35%26%11%2
900
16th to endNight
13%10%34%26%11%2
829
February1st to 15thNight
11%10%26%29%16%4
704
16th to endNight
11%6%30%32%16%3
632
March1st to 15thNight
10%6%40%30%12%1
720
16th to endNight
14%8%34%31%10%1
768
April1st to 15thNight
15%8%32%31%11%
606
16th to endNight
17%7%28%33%11%1
540
May1st to 15thNight
13%6%27%30%20%1
480
16th to endNight
20%425%27%20%1
375
June1st to 15thNight
17%6%30%27%16%1
360
16th to endNight
10%429%35%20%
360
July1st to 15thNight
8%319%45%21%1
340
16th to endNight
5%225%42%21%1
376
August1st to 15thNight
6%120%42%26%2
447
16th to endNight
7%224%39%24%1
573
September1st to 15thNight
13%322%34%23%2
633
16th to endNight
10%5%30%33%16%2
671
October1st to 15thNight
17%6%28%30%13%3
660
16th to endNight
11%7%31%35%13%
704
November1st to 15thNight
10%11%44%23%7%2
836
16th to endNight
12%9%39%28%8%1
900
December1st to 15thNight
10%9%32%32%12%2
900
16th to endNight
13%9%33%29%11%3
960
Page generated at 2017-09-20 02:49:48. Version ac04

Copyright 2017 A. Danko


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