Monroe
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Monroe clear sky chart from 2005-11-05 to 2019-06-02.

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
53%
17784
25%
53901
19%
17739
59%
17739
32%
32062

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
37%
1049
26%
2717
12%
1045
45%
1045
31%
1766
January16th to endNight
32%
1120
26%
2912
10%
1120
41%
1120
30%
1931
February1st to 15thNight
34%
936
22%
2584
9%
933
42%
933
27%
1707
February16th to endNight
26%
701
24%
2171
10%
701
37%
701
23%
1412
March1st to 15thNight
36%
630
24%
2310
17%
630
46%
630
23%
1394
March16th to endNight
43%
672
21%
2461
17%
672
52%
672
27%
1427
April1st to 15thNight
43%
629
26%
2097
18%
629
56%
629
33%
1165
April16th to endNight
47%
624
26%
2078
22%
624
56%
624
31%
1178
May1st to 15thNight
53%
630
23%
2100
21%
630
61%
630
31%
1219
May16th to endNight
64%
659
25%
2035
24%
657
68%
657
39%
1113
June1st to 15thNight
79%
588
20%
1764
23%
588
82%
588
43%
953
June16th to endNight
75%
585
21%
1755
23%
585
77%
585
37%
1011
July1st to 15thNight
79%
555
18%
1665
21%
555
80%
555
38%
942
July16th to endNight
85%
612
21%
1738
25%
579
85%
579
42%
953
August1st to 15thNight
84%
575
22%
1839
26%
572
84%
572
41%
980
August16th to endNight
76%
621
19%
2070
24%
621
76%
621
30%
1226
September1st to 15thNight
71%
585
22%
1950
25%
585
72%
585
31%
1158
September16th to endNight
71%
658
31%
2123
31%
658
72%
658
36%
1188
October1st to 15thNight
65%
780
30%
2340
24%
780
68%
780
39%
1296
October16th to endNight
57%
832
35%
2496
26%
832
65%
832
42%
1352
November1st to 15thNight
53%
820
29%
2460
24%
820
58%
820
36%
1427
November16th to endNight
46%
840
32%
2558
22%
840
56%
840
35%
1467
December1st to 15thNight
39%
963
25%
2766
15%
963
47%
963
28%
1775
December16th to endNight
35%
1120
20%
2912
10%
1120
41%
1120
25%
2022

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
12%5%25%5%345%5%7%42%
54399
Night
11%42442445%7%49%
54099
TransparencyDay
39%6%11%19%18%5%
54100
Night
34%5%11%20%21%7%
53903
SeeingDay
12%418%23%27%13%
7737
Night
14%422%31%23%4
17785

By Month

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
18%6%25%42234443%
1881
16th to endDay
18%8%3431323446%
2016
February1st to 15thDay
18%7%3442444441%
1935
16th to endDay
20%8%35%5%23325%38%
1885
March1st to 15thDay
17%7%35%5%3444439%
2310
16th to endDay
10%6%35%5%3445%6%44%
2463
April1st to 15thDay
12%6%245%3445%8%43%
2511
16th to endDay
10%5%36%6%2445%8%42%
2487
May1st to 15thDay
13%6%35%5%345%5%7%39%
2511
16th to endDay
6%315%6%45%6%6%10%42%
2779
June1st to 15thDay
5%3245%35%7%8%9%41%
2549
16th to endDay
5%325%6%47%7%7%10%38%
2535
July1st to 15thDay
8%325%6%47%7%7%11%34%
2535
16th to endDay
7%426%5%47%7%8%10%34%
2674
August1st to 15thDay
7%3246%45%6%6%11%42%
2363
16th to endDay
11%325%6%5%6%6%8%9%35%
2484
September1st to 15thDay
10%5%246%45%6%6%9%38%
2340
16th to endDay
10%4244345%5%7%47%
2148
October1st to 15thDay
7%4245%3345%6%53%
1950
16th to endDay
13%41431223457%
2080
November1st to 15thDay
10%6%2432235%5%51%
2058
16th to endDay
13%6%2342444449%
2052
December1st to 15thDay
19%9%26%42433439%
1837
16th to endDay
18%8%36%5%23346%37%
2016
January1st to 15thNight
16%6%25%423345%47%
2717
16th to endNight
18%6%24423335%46%
2912
February1st to 15thNight
15%7%35%424445%44%
2575
16th to endNight
18%7%24423345%42%
2171
March1st to 15thNight
15%5%24424347%43%
2310
16th to endNight
11%6%1442445%5%49%
2461
April1st to 15thNight
9%42332435%7%51%
2097
16th to endNight
9%5%2442435%6%52%
2078
May1st to 15thNight
9%43442345%9%47%
2099
16th to endNight
6%31442446%11%50%
2035
June1st to 15thNight
42133245%7%9%55%
1764
16th to endNight
5%323435%5%6%9%50%
1755
July1st to 15thNight
6%213435%47%11%47%
1755
16th to endNight
5%2123246%9%12%49%
1846
August1st to 15thNight
32124245%7%13%51%
1849
16th to endNight
8%3244335%8%11%43%
2070
September1st to 15thNight
8%4145%3446%7%47%
1950
16th to endNight
8%413434345%55%
2123
October1st to 15thNight
6%3245%24346%56%
2340
16th to endNight
11%31331223460%
2496
November1st to 15thNight
12%414313436%53%
2460
16th to endNight
12%5%33413335%53%
2558
December1st to 15thNight
17%7%24313336%45%
2766
16th to endNight
18%7%26%42333441%
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
43%35%19%21%6%
1882
16th to endDay
43%2318%24%7%
2016
February1st to 15thDay
46%36%18%17%7%
1937
16th to endDay
50%26%15%19%5%
1885
March1st to 15thDay
47%38%15%18%6%
2310
16th to endDay
39%5%10%18%22%2
2465
April1st to 15thDay
39%49%21%17%6%
2511
16th to endDay
40%5%8%19%21%4
2487
May1st to 15thDay
44%5%10%18%16%4
2511
16th to endDay
34%7%15%27%13%1
2783
June1st to 15thDay
33%10%14%23%16%
2549
16th to endDay
35%9%16%20%16%2
2535
July1st to 15thDay
37%9%21%21%8%1
2396
16th to endDay
39%10%17%21%11%
2519
August1st to 15thDay
32%10%18%23%13%1
2349
16th to endDay
40%8%16%20%11%2
2484
September1st to 15thDay
39%9%12%18%14%5%
2340
16th to endDay
35%5%10%19%21%7%
2148
October1st to 15thDay
30%5%9%19%20%14%
1950
16th to endDay
32%2316%31%13%
2080
November1st to 15thDay
34%38%19%26%7%
2058
16th to endDay
37%36%15%27%9%
2052
December1st to 15thDay
48%37%16%15%7%
1837
16th to endDay
48%47%18%17%3
2016
January1st to 15thNight
39%36%16%25%7%
2717
16th to endNight
41%35%17%22%9%
2912
February1st to 15thNight
42%46%19%19%7%
2584
16th to endNight
44%46%16%18%9%
2171
March1st to 15thNight
40%49%15%21%8%
2310
16th to endNight
35%5%9%20%23%5%
2461
April1st to 15thNight
30%5%11%22%20%9%
2097
16th to endNight
33%5%7%21%25%7%
2078
May1st to 15thNight
33%6%10%23%18%7%
2100
16th to endNight
27%5%15%28%21%1
2037
June1st to 15thNight
22%7%17%30%19%1
1764
16th to endNight
28%7%15%24%20%3
1755
July1st to 15thNight
26%8%26%25%11%2
1665
16th to endNight
22%9%24%28%13%1
1738
August1st to 15thNight
22%8%22%25%16%3
1839
16th to endNight
31%9%21%20%14%3
2070
September1st to 15thNight
32%8%15%22%13%8%
1950
16th to endNight
30%5%9%18%25%10%
2123
October1st to 15thNight
28%49%18%22%15%
2340
16th to endNight
28%25%16%29%18%
2496
November1st to 15thNight
31%410%18%24%10%
2460
16th to endNight
33%26%15%28%13%
2558
December1st to 15thNight
41%39%18%18%7%
2766
16th to endNight
46%37%18%18%4
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
25%8%38%18%6%1
180
16th to endDay
19%14%42%18%41
192
February1st to 15thDay
24%16%35%19%4
180
16th to endDay
32%11%36%15%2
159
March1st to 15thDay
23%17%38%20%
180
16th to endDay
8%15%40%25%8%1
193
April1st to 15thDay
20%10%28%26%12%1
390
16th to endDay
14%8%22%32%19%2
379
May1st to 15thDay
15%327%29%19%4
408
16th to endDay
7%321%29%27%11%
610
June1st to 15thDay
8%6%31%37%14%
576
16th to endDay
7%18%28%36%17%
570
July1st to 15thDay
5%15%23%40%23%
550
16th to endDay
7%1219%43%25%
595
August1st to 15thDay
7%217%46%25%
426
16th to endDay
12%315%36%30%
396
September1st to 15thDay
10%18%18%37%24%
375
16th to endDay
9%17%21%39%20%
274
October1st to 15thDay
321%27%31%15%
180
16th to endDay
17%325%26%21%6%
192
November1st to 15thDay
22%6%32%27%10%1
180
16th to endDay
15%9%29%26%13%6%
180
December1st to 15thDay
30%6%36%13%12%1
180
16th to endDay
21%15%34%19%7%1
192
January1st to 15thNight
20%7%29%32%9%
1050
16th to endNight
21%7%34%30%6%
1120
February1st to 15thNight
19%10%32%30%6%
936
16th to endNight
22%10%36%27%3
701
March1st to 15thNight
16%7%35%33%7%
630
16th to endNight
13%5%33%32%13%
672
April1st to 15thNight
10%9%35%32%12%
629
16th to endNight
12%6%29%36%14%1
624
May1st to 15thNight
10%127%41%17%1
630
16th to endNight
7%317%34%33%4
659
June1st to 15thNight
46%39%42%5%
588
16th to endNight
5%8%27%47%10%
585
July1st to 15thNight
5%427%48%13%
555
16th to endNight
5%222%54%14%
612
August1st to 15thNight
3319%54%18%
575
16th to endNight
10%325%47%12%
621
September1st to 15thNight
11%6%31%38%10%
585
16th to endNight
9%16%32%43%6%
658
October1st to 15thNight
8%117%31%34%6%
780
16th to endNight
13%420%33%23%4
832
November1st to 15thNight
14%323%34%21%2
820
16th to endNight
14%5%28%31%18%1
840
December1st to 15thNight
22%6%27%33%10%
963
16th to endNight
24%9%26%30%8%
1120
Page generated at 2019-06-02 18:43:10. Version ac04

Copyright 2019 A. Danko


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