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 2005-11-06 to 2024-01-12.

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
39%
23547
15%
74594
9%
23511
46%
23511
23%
48124

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 10thNight
32%
947
13%
2836
7%
946
37%
946
17%
2059
January11th to 20thNight
34%
910
15%
2730
9%
910
40%
910
19%
1913
January21st to endNight
31%
793
19%
2773
11%
793
43%
793
18%
1841
February1st to 10thNight
35%
720
13%
2459
11%
720
39%
720
16%
1725
February11th to 20thNight
36%
702
12%
2273
8%
700
41%
700
16%
1651
February21st to endNight
39%
592
14%
1845
9%
592
45%
592
19%
1285
March1st to 10thNight
35%
720
14%
2142
9%
720
42%
720
21%
1497
March11th to 20thNight
37%
720
18%
1980
9%
720
45%
720
23%
1392
March21st to endNight
35%
792
10%
2178
3%
792
40%
792
20%
1579
April1st to 10thNight
32%
642
14%
1747
5%
642
39%
642
19%
1256
April11th to 20thNight
36%
533
16%
1601
9%
533
41%
533
20%
1121
April21st to endNight
38%
540
13%
1620
9%
540
43%
540
20%
1116
May1st to 10thNight
43%
540
10%
1562
8%
540
46%
540
22%
1071
May11th to 20thNight
51%
354
15%
1239
16%
354
54%
354
25%
739
May21st to endNight
45%
388
7%
1358
5%
388
47%
388
16%
944
June1st to 10thNight
41%
360
4%
1260
3%
360
42%
360
19%
819
June11th to 20thNight
39%
360
3%
1260
1%
360
41%
360
19%
816
June21st to endNight
54%
360
4%
1260
1%
360
55%
360
31%
680
July1st to 10thNight
62%
350
5%
1225
3%
350
63%
350
32%
671
July11th to 20thNight
55%
348
9%
1218
9%
348
58%
348
32%
667
July21st to endNight
65%
394
19%
1344
20%
372
73%
372
45%
606
August1st to 10thNight
62%
397
17%
1463
20%
395
66%
395
32%
763
August11th to 20thNight
62%
534
19%
1602
16%
534
66%
534
42%
865
August21st to endNight
59%
594
26%
1782
19%
594
63%
594
41%
958
September1st to 10thNight
51%
589
20%
1727
13%
589
56%
589
34%
1031
September11th to 20thNight
55%
720
22%
1980
14%
720
59%
720
36%
1216
September21st to endNight
44%
720
23%
1980
13%
720
52%
720
36%
1199
October1st to 10thNight
44%
720
21%
2088
13%
720
52%
720
28%
1326
October11th to 20thNight
39%
720
20%
2232
10%
720
50%
720
27%
1383
October21st to endNight
35%
792
19%
2574
11%
792
45%
792
22%
1664
November1st to 10thNight
27%
862
16%
2527
7%
862
37%
862
20%
1765
November11th to 20thNight
30%
950
20%
2660
9%
950
39%
950
25%
1781
November21st to endNight
33%
950
15%
2829
7%
950
41%
950
24%
1846
December1st to 10thNight
36%
950
16%
2850
10%
950
42%
950
20%
1958
December11th to 20thNight
30%
949
12%
3462
6%
949
36%
949
17%
2239
December21st to endNight
29%
1035
10%
4928
6%
1026
36%
1026
13%
2682

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%8%36%6%35%5%6%8%40%
74634
Night
7%8%47%6%35%5%6%8%39%
75091
TransparencyDay
39%8%15%24%11%2
74318
Night
40%8%15%22%12%2
74925
SeeingDay
12%9%25%29%19%6%
14250
Night
11%8%31%32%15%2
23564

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 10thDay
6%10%49%7%45%5%6%9%35%
1329
11th to 20thDay
6%8%5%9%7%46%5%7%9%33%
1284
21st to endDay
6%10%410%8%46%7%7%9%30%
1584
February1st to 10thDay
7%11%5%9%9%5%7%6%5%8%29%
1500
11th to 20thDay
6%12%6%9%9%5%5%7%6%7%28%
1575
21st to endDay
5%12%7%10%8%5%45%6%8%30%
1408
March1st to 10thDay
5%11%5%9%8%46%6%5%8%30%
1818
11th to 20thDay
7%9%48%8%45%5%6%9%36%
1979
21st to endDay
8%11%6%8%7%45%6%6%9%30%
2178
April1st to 10thDay
10%10%5%8%7%46%5%6%8%30%
2209
11th to 20thDay
11%11%38%6%46%6%7%7%32%
2310
21st to endDay
11%10%37%6%35%6%6%8%34%
2340
May1st to 10thDay
12%8%46%6%45%6%7%8%34%
2397
11th to 20thDay
11%6%36%5%36%6%7%9%38%
2650
21st to endDay
19%8%36%5%35%5%6%7%33%
2917
June1st to 10thDay
13%7%25%6%46%6%6%10%35%
2700
11th to 20thDay
16%8%27%6%35%6%7%9%31%
2700
21st to endDay
7%4245%35%5%7%10%48%
2700
July1st to 10thDay
6%3245%345%6%9%52%
2700
11th to 20thDay
6%324425%5%6%10%52%
2700
21st to endDay
5%21332345%9%62%
2891
August1st to 10thDay
7%4244345%6%9%53%
2466
11th to 20thDay
6%425%3246%6%9%53%
2299
21st to endDay
9%4243245%5%9%54%
2574
September1st to 10thDay
10%5%23433447%55%
2230
11th to 20thDay
14%6%2442345%7%48%
1980
21st to endDay
8%8%25%43445%8%49%
1980
October1st to 10thDay
13%9%36%6%45%5%5%7%38%
1872
11th to 20thDay
9%8%36%6%36%5%6%7%41%
1728
21st to endDay
8%9%36%7%45%6%7%8%38%
1782
November1st to 10thDay
10%14%47%6%45%5%7%7%31%
1531
11th to 20thDay
6%10%37%7%345%6%10%39%
1520
21st to endDay
49%6%9%5%346%7%9%36%
1349
December1st to 10thDay
6%12%5%10%6%46%46%7%35%
1330
11th to 20thDay
410%5%10%8%5%6%5%7%7%32%
1682
21st to endDay
48%36%6%36%5%6%8%45%
2442
January1st to 10thNight
410%5%9%8%47%6%7%9%29%
2836
11th to 20thNight
6%9%410%7%46%6%7%9%33%
2730
21st to endNight
6%11%48%7%46%6%7%8%34%
2773
February1st to 10thNight
7%9%5%9%8%5%7%6%5%7%31%
2459
11th to 20thNight
6%13%6%9%7%5%6%6%6%8%28%
2272
21st to endNight
411%7%10%7%5%5%6%6%7%32%
1845
March1st to 10thNight
5%11%5%8%7%46%6%8%9%32%
2142
11th to 20thNight
7%10%5%8%5%36%7%6%9%35%
1980
21st to endNight
7%10%5%9%8%45%5%8%9%31%
2178
April1st to 10thNight
8%11%48%7%45%5%7%9%32%
1747
11th to 20thNight
10%12%5%8%5%36%5%6%8%32%
1601
21st to endNight
11%10%36%7%46%6%7%7%34%
1620
May1st to 10thNight
10%10%49%6%35%5%6%8%35%
1562
11th to 20thNight
10%5%245%36%5%5%9%43%
1239
21st to endNight
16%7%37%6%46%6%6%8%31%
1358
June1st to 10thNight
14%6%46%445%5%7%8%37%
1260
11th to 20thNight
17%6%25%5%46%5%8%9%33%
1260
21st to endNight
5%435%5%35%6%7%10%48%
1260
July1st to 10thNight
6%314445%5%8%10%49%
1260
11th to 20thNight
7%5%26%425%5%6%8%52%
1260
21st to endNight
3213425%46%9%62%
1423
August1st to 10thNight
6%425%5%335%6%8%54%
1471
11th to 20thNight
5%4134246%6%10%54%
1602
21st to endNight
7%32432445%7%57%
1782
September1st to 10thNight
10%5%244345%6%8%48%
1727
11th to 20thNight
11%5%25%423447%52%
1980
21st to endNight
7%5%25%5%35%46%8%48%
1980
October1st to 10thNight
11%7%35%5%345%5%8%44%
2088
11th to 20thNight
9%7%36%5%35%5%6%8%44%
2232
21st to endNight
8%7%37%8%35%47%8%40%
2574
November1st to 10thNight
10%12%48%6%45%5%5%8%34%
2527
11th to 20thNight
5%9%5%7%6%35%6%7%8%40%
2660
21st to endNight
5%10%47%5%35%47%10%39%
2829
December1st to 10thNight
5%11%49%7%46%5%6%8%36%
2850
11th to 20thNight
38%5%9%7%46%6%7%9%35%
3510
21st to endNight
5%9%46%6%36%5%5%8%44%
5214

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 10thDay
46%8%15%21%8%2
1329
11th to 20thDay
45%8%16%21%7%2
1284
21st to endDay
47%9%16%18%9%2
1584
February1st to 10thDay
54%7%14%17%8%1
1500
11th to 20thDay
51%10%15%17%6%1
1584
21st to endDay
52%7%12%17%11%1
1408
March1st to 10thDay
51%8%15%17%9%
1818
11th to 20thDay
44%8%15%22%9%1
1980
21st to endDay
49%9%15%20%6%
2178
April1st to 10thDay
49%8%15%20%7%
2209
11th to 20thDay
49%7%12%21%9%2
2310
21st to endDay
44%8%15%22%10%1
2340
May1st to 10thDay
44%9%15%23%9%
2397
11th to 20thDay
39%9%14%26%12%1
2654
21st to endDay
48%7%15%21%9%
2918
June1st to 10thDay
43%8%18%20%9%1
2700
11th to 20thDay
45%9%16%20%9%1
2700
21st to endDay
29%8%19%29%12%3
2700
July1st to 10thDay
26%9%17%32%13%3
2626
11th to 20thDay
25%9%17%30%16%3
2619
21st to endDay
18%7%17%30%24%4
2730
August1st to 10thDay
25%7%16%32%16%3
2449
11th to 20thDay
25%7%18%34%12%3
2299
21st to endDay
26%6%15%31%19%3
2574
September1st to 10thDay
30%5%14%27%16%7%
2230
11th to 20thDay
34%7%13%29%14%3
1980
21st to endDay
33%7%13%31%12%3
1980
October1st to 10thDay
43%8%15%23%10%1
1872
11th to 20thDay
41%8%15%25%10%2
1728
21st to endDay
42%7%16%23%11%1
1782
November1st to 10thDay
50%8%13%20%8%1
1531
11th to 20thDay
41%8%17%24%9%
1520
21st to endDay
41%8%17%22%10%2
1349
December1st to 10thDay
49%7%13%18%9%3
1330
11th to 20thDay
48%7%16%24%41
1684
21st to endDay
34%7%15%22%20%1
2442
January1st to 10thNight
49%9%14%18%8%2
2836
11th to 20thNight
46%9%16%20%8%2
2730
21st to endNight
46%7%15%18%12%2
2773
February1st to 10thNight
50%7%13%16%11%2
2459
11th to 20thNight
51%9%13%18%8%
2273
21st to endNight
48%7%15%18%10%2
1845
March1st to 10thNight
45%9%15%22%7%1
2142
11th to 20thNight
45%7%15%21%11%1
1980
21st to endNight
47%10%17%19%7%1
2178
April1st to 10thNight
47%9%13%20%11%
1747
11th to 20thNight
48%7%12%20%10%1
1601
21st to endNight
45%9%12%24%9%2
1620
May1st to 10thNight
44%8%13%23%11%1
1562
11th to 20thNight
36%8%15%27%12%2
1239
21st to endNight
47%10%14%18%8%2
1358
June1st to 10thNight
42%9%14%24%10%1
1260
11th to 20thNight
42%8%16%22%9%2
1260
21st to endNight
29%8%19%27%16%2
1260
July1st to 10thNight
26%10%17%29%15%2
1225
11th to 20thNight
29%8%17%23%18%6%
1218
21st to endNight
17%7%15%28%28%5%
1344
August1st to 10thNight
27%8%17%28%16%4
1463
11th to 20thNight
24%6%19%28%18%4
1602
21st to endNight
25%6%12%30%21%5%
1782
September1st to 10thNight
31%8%13%25%18%6%
1727
11th to 20thNight
32%6%12%28%17%5%
1980
21st to endNight
32%6%15%28%15%4
1980
October1st to 10thNight
37%7%15%24%15%2
2088
11th to 20thNight
37%7%15%24%14%3
2232
21st to endNight
41%8%14%25%11%1
2574
November1st to 10thNight
48%7%14%21%10%2
2527
11th to 20thNight
39%9%17%20%14%1
2660
21st to endNight
40%8%20%20%10%3
2829
December1st to 10thNight
47%6%15%20%10%2
2850
11th to 20thNight
43%9%22%21%41
3507
21st to endNight
37%7%14%24%15%4
5214

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 10thDay
414%29%28%13%11%
180
11th to 20thDay
7%10%32%28%18%6%
163
21st to endDay
10%10%33%27%15%5%
176
February1st to 10thDay
14%10%36%30%9%2
188
11th to 20thDay
9%12%33%32%12%2
240
21st to endDay
10%11%26%34%15%4
274
March1st to 10thDay
10%14%35%24%13%5%
420
11th to 20thDay
8%12%30%26%19%6%
420
21st to endDay
11%10%32%25%17%5%
462
April1st to 10thDay
13%14%30%26%15%2
420
11th to 20thDay
14%8%29%28%17%5%
412
21st to endDay
14%12%27%27%15%4
420
May1st to 10thDay
13%11%22%27%20%8%
480
11th to 20thDay
15%6%22%27%24%6%
625
21st to endDay
17%7%20%30%18%8%
679
June1st to 10thDay
14%10%24%31%17%4
630
11th to 20thDay
16%10%27%30%15%2
630
21st to endDay
7%425%32%24%8%
630
July1st to 10thDay
7%418%35%28%9%
621
11th to 20thDay
7%5%22%35%22%8%
618
21st to endDay
4421%37%26%9%
637
August1st to 10thDay
8%420%35%26%8%
447
11th to 20thDay
9%417%32%26%12%
437
21st to endDay
9%6%20%30%25%11%
495
September1st to 10thDay
12%8%25%28%21%6%
450
11th to 20thDay
15%8%22%27%21%6%
450
21st to endDay
14%12%25%31%13%4
450
October1st to 10thDay
18%9%19%24%23%7%
342
11th to 20thDay
12%12%29%24%18%5%
270
21st to endDay
17%17%27%24%13%2
297
November1st to 10thDay
22%12%28%25%11%2
270
11th to 20thDay
12%14%36%27%9%2
270
21st to endDay
5%13%37%22%15%7%
189
December1st to 10thDay
8%12%32%29%14%5%
180
11th to 20thDay
12%17%37%22%11%2
180
21st to endDay
12%7%28%26%21%6%
198
January1st to 10thNight
10%14%34%27%14%1
950
11th to 20thNight
10%10%35%30%12%2
910
21st to endNight
13%11%36%28%11%2
793
February1st to 10thNight
10%11%30%31%14%4
720
11th to 20thNight
11%9%33%33%12%2
704
21st to endNight
11%6%28%30%22%4
592
March1st to 10thNight
9%6%36%33%14%3
720
11th to 20thNight
11%10%32%33%12%2
720
21st to endNight
12%9%30%31%14%3
792
April1st to 10thNight
12%10%33%31%13%1
642
11th to 20thNight
17%7%31%32%12%1
533
21st to endNight
15%9%28%33%14%1
540
May1st to 10thNight
14%9%24%33%20%1
540
11th to 20thNight
12%6%27%31%22%2
354
21st to endNight
19%6%22%32%20%2
389
June1st to 10thNight
18%6%28%30%16%3
360
11th to 20thNight
18%8%28%34%12%
360
21st to endNight
7%428%39%22%1
360
July1st to 10thNight
7%420%45%23%1
350
11th to 20thNight
7%425%45%18%2
348
21st to endNight
4324%45%22%2
394
August1st to 10thNight
9%318%43%25%2
397
11th to 20thNight
7%222%44%22%2
534
21st to endNight
8%324%40%23%2
594
September1st to 10thNight
12%426%37%19%2
589
11th to 20thNight
15%5%20%37%22%2
720
21st to endNight
10%7%33%34%14%3
720
October1st to 10thNight
15%7%25%33%18%3
720
11th to 20thNight
12%7%34%29%16%2
720
21st to endNight
13%9%34%32%12%1
792
November1st to 10thNight
17%9%39%24%9%1
862
11th to 20thNight
9%13%41%27%8%2
950
21st to endNight
10%14%35%29%10%1
950
December1st to 10thNight
10%11%32%31%14%2
950
11th to 20thNight
8%11%37%31%11%1
950
21st to endNight
13%10%34%29%11%2
1045
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