Little Bennett Regional Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Little Bennett Regional Park clear sky chart from 2005-11-05 to 2018-02-22.

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%
15844
20%
48936
11%
15805
48%
15805
24%
30926

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
21%
777
21%
2625
8%
776
38%
776
19%
1655
January16th to endNight
20%
832
22%
2704
7%
832
39%
832
21%
1695
February1st to 15thNight
21%
763
18%
2482
5%
761
37%
761
19%
1565
February16th to endNight
16%
659
23%
2011
5%
659
37%
659
20%
1288
March1st to 15thNight
24%
720
21%
2001
8%
720
37%
720
23%
1309
March16th to endNight
22%
768
20%
2091
8%
768
33%
768
23%
1410
April1st to 15thNight
26%
718
18%
1796
4%
718
34%
718
27%
1221
April16th to endNight
39%
720
18%
1800
7%
720
44%
720
29%
1219
May1st to 15thNight
37%
545
17%
1625
9%
545
44%
545
23%
1102
May16th to endNight
50%
374
17%
1497
15%
374
58%
374
22%
893
June1st to 15thNight
52%
360
18%
1440
18%
360
60%
360
24%
830
June16th to endNight
58%
360
17%
1440
18%
360
65%
360
25%
824
July1st to 15thNight
60%
340
11%
1360
13%
340
62%
340
17%
887
July16th to endNight
70%
545
16%
1576
13%
512
75%
512
36%
893
August1st to 15thNight
67%
539
18%
1609
15%
536
68%
536
30%
1023
August16th to endNight
64%
747
20%
1893
14%
747
64%
747
34%
1245
September1st to 15thNight
56%
720
24%
1800
13%
720
60%
720
35%
1179
September16th to endNight
52%
717
24%
1978
19%
717
56%
717
30%
1301
October1st to 15thNight
46%
720
23%
2160
20%
720
54%
720
27%
1396
October16th to endNight
36%
768
29%
2304
17%
768
51%
768
32%
1344
November1st to 15thNight
36%
760
24%
2414
14%
760
50%
760
27%
1459
November16th to endNight
30%
780
23%
2688
13%
780
45%
780
22%
1574
December1st to 15thNight
25%
780
17%
2730
6%
780
39%
780
17%
1771
December16th to endNight
21%
832
21%
2912
7%
832
39%
832
18%
1843

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
14%5%2443445%7%41%
49307
Night
13%5%2442445%7%43%
49118
Cloud CoverDay
14%5%245%3445%7%41%
49317
Night
13%5%2442445%7%43%
49122
TransparencyDay
40%6%12%22%15%2
49007
Night
39%5%11%23%16%2
48936
SeeingDay
17%10%24%24%16%6%
6130
Night
17%10%29%28%12%1
15849

By Month

Percentage Cloud Cover NE (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
16%6%25%3345%47%40%
1640
16th to endDay
14%8%35%424346%41%
1872
February1st to 15thDay
14%7%35%6%35%5%5%437%
1710
16th to endDay
14%7%35%5%33446%40%
1609
March1st to 15thDay
15%6%345%35%436%42%
1945
16th to endDay
15%7%36%5%24446%39%
2133
April1st to 15thDay
14%5%245%2436%7%42%
2152
16th to endDay
17%6%24423346%44%
2160
May1st to 15thDay
16%5%35%4345%6%8%36%
2336
16th to endDay
16%425%5%345%5%8%39%
2618
June1st to 15thDay
11%414436%5%6%10%41%
2520
16th to endDay
10%4145%25%5%6%9%44%
2520
July1st to 15thDay
9%5%246%36%6%6%8%39%
2520
16th to endDay
7%315%5%37%7%8%9%39%
2483
August1st to 15thDay
12%425%6%45%5%7%9%34%
2340
16th to endDay
11%5%145%25%5%6%9%42%
2295
September1st to 15thDay
15%424423348%46%
2160
16th to endDay
14%5%25%5%2445%7%41%
1978
October1st to 15thDay
19%5%2332335%6%44%
1800
16th to endDay
13%5%24423445%49%
1920
November1st to 15thDay
13%6%2342336%6%45%
1773
16th to endDay
16%5%24324446%45%
1599
December1st to 15thDay
16%5%25%5%3446%7%38%
1560
16th to endDay
16%7%25%43445%6%38%
1664
January1st to 15thNight
16%6%2443445%7%41%
2625
16th to endNight
15%7%25%434446%42%
2704
February1st to 15thNight
14%7%2442445%6%42%
2480
16th to endNight
14%8%25%4245%47%40%
2011
March1st to 15thNight
16%6%15%424446%43%
1989
16th to endNight
15%6%25%424346%42%
2091
April1st to 15thNight
12%5%35%5%35%46%7%41%
1796
16th to endNight
15%43343445%7%43%
1800
May1st to 15thNight
17%7%35%42346%7%37%
1625
16th to endNight
12%5%24425%46%9%42%
1495
June1st to 15thNight
11%314435%5%6%10%43%
1440
16th to endNight
8%425%435%5%6%9%44%
1440
July1st to 15thNight
8%5%25%6%47%6%7%9%35%
1440
16th to endNight
5%313426%6%7%11%46%
1683
August1st to 15thNight
8%425%435%5%7%8%43%
1620
16th to endNight
9%424435%5%6%8%45%
1893
September1st to 15thNight
12%5%2433345%7%47%
1800
16th to endNight
12%7%25%5%23446%46%
1978
October1st to 15thNight
18%414423435%44%
2160
16th to endNight
14%413323346%51%
2304
November1st to 15thNight
13%6%25%423335%49%
2414
16th to endNight
14%42443345%7%45%
2688
December1st to 15thNight
16%5%36%5%345%46%37%
2730
16th to endNight
16%7%25%42445%8%39%
2912

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
16%6%25%3245%5%7%40%
1640
16th to endDay
15%8%25%424436%42%
1872
February1st to 15thDay
14%7%35%5%36%5%5%5%37%
1710
16th to endDay
14%7%36%434346%40%
1609
March1st to 15thDay
15%6%35%435%436%42%
1956
16th to endDay
15%7%36%5%2435%6%39%
2132
April1st to 15thDay
14%5%2443345%7%43%
2152
16th to endDay
17%6%2432335%6%43%
2160
May1st to 15thDay
16%5%245%345%6%8%36%
2336
16th to endDay
15%5%15%5%3445%8%39%
2618
June1st to 15thDay
11%424435%5%7%10%41%
2520
16th to endDay
10%4236%245%6%9%44%
2520
July1st to 15thDay
9%5%245%36%5%7%9%39%
2520
16th to endDay
7%3145%37%7%8%10%38%
2483
August1st to 15thDay
12%5%246%46%5%7%8%35%
2340
16th to endDay
11%414435%5%7%8%42%
2295
September1st to 15thDay
15%414424348%46%
2160
16th to endDay
14%6%25%4245%48%41%
1978
October1st to 15thDay
19%5%2342335%6%44%
1800
16th to endDay
14%5%23423445%49%
1920
November1st to 15thDay
14%6%2342435%6%45%
1773
16th to endDay
15%5%14424446%45%
1599
December1st to 15thDay
16%5%25%5%3446%7%38%
1560
16th to endDay
17%7%25%434447%38%
1664
January1st to 15thNight
16%6%3432445%7%41%
2625
16th to endNight
16%7%3342435%6%42%
2704
February1st to 15thNight
14%7%245%2345%6%42%
2473
16th to endNight
13%8%25%42445%6%41%
2011
March1st to 15thNight
16%5%2442445%6%43%
2001
16th to endNight
15%6%345%24446%42%
2091
April1st to 15thNight
12%5%45%435%45%8%41%
1796
16th to endNight
14%5%24425%45%7%43%
1800
May1st to 15thNight
17%7%25%42345%7%38%
1624
16th to endNight
12%5%244245%5%9%42%
1495
June1st to 15thNight
10%324436%5%6%9%43%
1440
16th to endNight
7%5%25%5%35%45%10%44%
1440
July1st to 15thNight
8%5%26%6%46%7%7%8%36%
1440
16th to endNight
6%313426%6%7%10%46%
1683
August1st to 15thNight
8%425%5%35%47%8%44%
1620
16th to endNight
9%424435%5%6%8%45%
1893
September1st to 15thNight
12%5%145%3335%8%46%
1800
16th to endNight
12%6%25%5%24346%46%
1978
October1st to 15thNight
18%415%424445%44%
2160
16th to endNight
14%313313446%52%
2304
November1st to 15thNight
13%5%245%23345%49%
2414
16th to endNight
15%324424447%45%
2688
December1st to 15thNight
16%5%26%5%25%5%46%37%
2730
16th to endNight
16%6%3442435%8%39%
2912

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
42%6%12%21%13%3
1641
16th to endDay
43%312%23%13%3
1872
February1st to 15thDay
45%6%11%23%11%2
1712
16th to endDay
44%412%25%11%1
1609
March1st to 15thDay
42%412%22%15%2
1956
16th to endDay
44%5%11%18%17%2
2133
April1st to 15thDay
40%411%21%17%3
2152
16th to endDay
40%5%9%18%19%6%
2160
May1st to 15thDay
43%6%13%19%14%1
2336
16th to endDay
42%6%14%21%12%1
2622
June1st to 15thDay
35%8%14%26%12%1
2520
16th to endDay
34%8%14%22%16%1
2520
July1st to 15thDay
38%10%12%20%14%2
2371
16th to endDay
34%11%14%24%13%2
2327
August1st to 15thDay
42%8%13%20%14%1
2327
16th to endDay
36%8%13%24%15%2
2295
September1st to 15thDay
37%5%12%20%21%2
2160
16th to endDay
40%5%8%23%19%2
1978
October1st to 15thDay
40%410%24%16%3
1800
16th to endDay
36%410%28%19%1
1920
November1st to 15thDay
38%413%21%16%5%
1773
16th to endDay
39%410%27%16%1
1599
December1st to 15thDay
42%5%15%21%12%2
1560
16th to endDay
45%312%24%12%
1664
January1st to 15thNight
42%5%10%20%17%4
2625
16th to endNight
41%412%25%14%1
2704
February1st to 15thNight
41%5%12%23%14%2
2482
16th to endNight
42%49%26%15%1
2011
March1st to 15thNight
40%5%11%27%13%1
2001
16th to endNight
42%5%10%20%16%3
2091
April1st to 15thNight
40%5%10%20%18%3
1796
16th to endNight
39%5%10%20%17%6%
1800
May1st to 15thNight
44%6%10%21%14%2
1625
16th to endNight
37%8%17%20%14%2
1497
June1st to 15thNight
35%8%13%25%16%1
1440
16th to endNight
35%7%14%22%17%2
1440
July1st to 15thNight
42%11%13%16%11%4
1360
16th to endNight
27%8%20%23%18%2
1576
August1st to 15thNight
35%8%12%23%17%2
1609
16th to endNight
34%8%11%23%18%3
1893
September1st to 15thNight
36%6%12%20%21%3
1800
16th to endNight
39%5%8%21%20%3
1978
October1st to 15thNight
41%49%23%17%2
2160
16th to endNight
32%49%30%20%2
2304
November1st to 15thNight
37%48%23%19%6%
2414
16th to endNight
36%410%24%18%3
2688
December1st to 15thNight
45%5%12%23%11%1
2730
16th to endNight
43%5%13%24%11%1
2912

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%28%30%13%21
110
16th to endDay
19%29%32%15%2
144
February1st to 15thDay
25%23%43%6%
135
16th to endDay
18%18%43%17%1
230
March1st to 15thDay
17%22%29%22%6%
270
16th to endDay
19%17%32%20%6%3
288
April1st to 15thDay
17%16%28%21%12%2
270
16th to endDay
23%8%26%18%17%5%
270
May1st to 15thDay
26%15%22%19%10%5%
288
16th to endDay
20%420%26%21%6%
331
June1st to 15thDay
14%6%25%23%22%7%
315
16th to endDay
11%5%26%32%18%5%
315
July1st to 15thDay
15%123%27%24%7%
305
16th to endDay
9%111%35%29%11%
326
August1st to 15thDay
15%215%27%24%13%
313
16th to endDay
10%10%31%26%20%
332
September1st to 15thDay
15%6%18%20%22%16%
315
16th to endDay
20%414%27%20%13%
314
October1st to 15thDay
23%5%15%26%22%7%
315
16th to endDay
14%12%27%25%16%2
336
November1st to 15thDay
16%9%28%26%17%2
293
16th to endDay
18%17%33%18%10%1
129
December1st to 15thDay
18%24%30%14%8%3
90
16th to endDay
27%15%36%16%4
96
January1st to 15thNight
21%16%36%21%3
780
16th to endNight
20%17%38%21%1
832
February1st to 15thNight
20%16%36%24%1
764
16th to endNight
21%18%38%19%1
659
March1st to 15thNight
21%14%36%25%2
720
16th to endNight
19%14%40%19%5%1
768
April1st to 15thNight
15%17%38%23%4
718
16th to endNight
17%10%30%29%11%
720
May1st to 15thNight
19%8%28%29%12%
545
16th to endNight
15%5%20%38%18%1
375
June1st to 15thNight
11%26%35%24%
360
16th to endNight
10%120%50%16%1
360
July1st to 15thNight
12%115%43%26%1
340
16th to endNight
6%113%42%32%3
545
August1st to 15thNight
12%11%45%26%3
539
16th to endNight
12%113%38%28%4
747
September1st to 15thNight
14%222%29%28%2
720
16th to endNight
16%317%31%28%3
717
October1st to 15thNight
20%5%21%29%20%2
720
16th to endNight
17%11%33%25%12%
768
November1st to 15thNight
16%10%30%31%9%1
760
16th to endNight
18%16%30%26%7%
780
December1st to 15thNight
21%11%34%23%7%
780
16th to endNight
20%13%40%24%1
832
Page generated at 2018-02-23 11:21:29. Version ac04

Copyright 2018 A. Danko


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