Lamoine Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lamoine Observatory clear sky chart from 2005-11-05 to 2019-06-24.

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
23%
17189
16%
53959
6%
17152
34%
17152
15%
37150

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
12%
840
17%
2926
4%
836
29%
836
10%
1952
January16th to endNight
9%
896
14%
3083
1%
896
25%
896
9%
2127
February1st to 15thNight
10%
824
15%
2676
2%
821
26%
821
10%
1879
February16th to endNight
14%
735
16%
2211
3%
735
31%
735
13%
1537
March1st to 15thNight
14%
840
17%
2427
5%
840
28%
840
14%
1743
March16th to endNight
19%
896
19%
2464
6%
896
30%
896
18%
1702
April1st to 15thNight
15%
773
17%
2067
4%
773
25%
773
15%
1496
April16th to endNight
22%
623
12%
1869
3%
623
30%
623
15%
1349
May1st to 15thNight
25%
630
14%
1890
7%
630
32%
630
15%
1369
May16th to endNight
24%
567
11%
1794
7%
566
31%
566
13%
1321
June1st to 15thNight
30%
420
10%
1470
9%
420
36%
420
12%
1092
June16th to endNight
32%
406
9%
1422
7%
406
38%
406
14%
1005
July1st to 15thNight
39%
370
11%
1402
12%
370
44%
370
15%
919
July16th to endNight
34%
447
10%
1582
9%
422
41%
422
13%
1135
August1st to 15thNight
41%
574
11%
1713
8%
570
44%
570
17%
1221
August16th to endNight
46%
621
18%
1863
9%
621
51%
621
25%
1192
September1st to 15thNight
41%
765
17%
2078
9%
765
47%
765
29%
1351
September16th to endNight
39%
777
24%
2145
12%
777
48%
777
30%
1316
October1st to 15thNight
31%
780
20%
2258
8%
780
41%
780
22%
1505
October16th to endNight
20%
832
17%
2626
6%
832
33%
832
17%
1752
November1st to 15thNight
25%
820
19%
2667
9%
820
38%
820
16%
1768
November16th to endNight
17%
893
16%
2913
4%
893
31%
893
12%
1980
December1st to 15thNight
13%
900
15%
3053
3%
900
28%
900
11%
2137
December16th to endNight
10%
960
15%
3360
1%
960
26%
960
10%
2302

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
19%7%25%424447%37%
54856
Night
19%8%35%424446%36%
54133
TransparencyDay
46%6%11%21%12%1
54549
Night
48%5%11%20%12%1
53959
SeeingDay
23%19%29%19%7%1
8756
Night
22%24%25%19%7%
17189

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
15%9%35%5%14347%38%
1669
16th to endDay
16%9%35%423347%37%
1842
February1st to 15thDay
17%10%26%4345%5%7%32%
1845
16th to endDay
13%10%46%5%25%446%34%
1833
March1st to 15thDay
20%9%36%434346%33%
2181
16th to endDay
16%7%245%33346%41%
2464
April1st to 15thDay
20%8%34423336%36%
2541
16th to endDay
21%7%35%423346%35%
2696
May1st to 15thDay
23%8%35%5%23346%32%
2722
16th to endDay
22%7%35%42445%7%32%
3034
June1st to 15thDay
23%8%35%424447%30%
3150
16th to endDay
22%6%25%435%447%33%
3045
July1st to 15thDay
15%4244245%5%8%40%
2807
16th to endDay
16%7%25%4345%6%8%36%
2826
August1st to 15thDay
16%6%25%42435%8%39%
2488
16th to endDay
11%4245%2345%9%46%
2691
September1st to 15thDay
12%5%13435%447%48%
2210
16th to endDay
16%5%23322436%48%
2145
October1st to 15thDay
19%5%24324345%42%
2031
16th to endDay
21%5%24423445%40%
1947
November1st to 15thDay
22%5%24323346%39%
1851
16th to endDay
20%7%26%323445%37%
1705
December1st to 15thDay
23%8%24334345%35%
1565
16th to endDay
23%10%26%323335%34%
1568
January1st to 15thNight
16%8%35%424448%37%
2926
16th to endNight
15%11%36%6%2445%8%32%
3083
February1st to 15thNight
16%8%36%5%35%45%6%35%
2675
16th to endNight
16%9%35%5%24446%37%
2211
March1st to 15thNight
19%10%45%5%2335%5%34%
2415
16th to endNight
16%7%35%433346%40%
2464
April1st to 15thNight
22%9%245%33446%32%
2067
16th to endNight
25%8%36%422346%32%
1869
May1st to 15thNight
23%7%25%5%25%35%6%30%
1890
16th to endNight
24%8%36%434345%29%
1792
June1st to 15thNight
27%9%2442445%6%27%
1470
16th to endNight
23%8%35%424347%31%
1422
July1st to 15thNight
19%6%25%5%245%6%7%35%
1480
16th to endNight
21%8%36%5%3445%6%29%
1681
August1st to 15thNight
18%7%25%4245%6%8%32%
1725
16th to endNight
14%5%24433449%42%
1863
September1st to 15thNight
16%423424447%44%
2078
16th to endNight
14%424313347%48%
2145
October1st to 15thNight
20%6%23423446%41%
2258
16th to endNight
20%7%25%423436%39%
2626
November1st to 15thNight
20%6%24424445%40%
2667
16th to endNight
18%8%34324446%37%
2913
December1st to 15thNight
22%8%25%423336%35%
3053
16th to endNight
22%8%34413347%35%
3360

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
46%6%12%19%12%1
1670
16th to endDay
48%412%22%10%1
1842
February1st to 15thDay
52%5%14%17%8%
1848
16th to endDay
49%412%19%11%2
1833
March1st to 15thDay
52%5%12%18%10%1
2192
16th to endDay
43%5%9%17%19%4
2464
April1st to 15thDay
47%49%19%15%3
2541
16th to endDay
48%5%10%17%13%3
2696
May1st to 15thDay
52%5%9%18%12%2
2722
16th to endDay
50%7%10%21%9%1
3038
June1st to 15thDay
52%6%11%18%10%1
3150
16th to endDay
50%6%10%18%12%1
3045
July1st to 15thDay
39%8%15%22%13%
2657
16th to endDay
44%9%14%21%9%1
2663
August1st to 15thDay
42%7%14%25%8%
2475
16th to endDay
33%6%14%26%17%
2691
September1st to 15thDay
34%7%12%24%18%2
2210
16th to endDay
37%5%10%28%18%1
2145
October1st to 15thDay
42%5%10%25%13%1
2031
16th to endDay
45%413%23%12%
1947
November1st to 15thDay
46%5%11%21%13%1
1851
16th to endDay
49%5%13%18%11%
1705
December1st to 15thDay
51%5%12%22%7%
1565
16th to endDay
53%49%19%11%
1568
January1st to 15thNight
47%6%13%22%9%
2926
16th to endNight
50%5%12%21%8%
3083
February1st to 15thNight
50%6%13%18%10%1
2676
16th to endNight
49%410%20%13%2
2211
March1st to 15thNight
52%49%19%12%1
2427
16th to endNight
45%5%9%17%20%2
2464
April1st to 15thNight
52%49%15%15%2
2067
16th to endNight
54%48%15%12%3
1869
May1st to 15thNight
52%6%8%17%13%1
1890
16th to endNight
55%5%8%19%9%1
1794
June1st to 15thNight
56%7%9%17%7%2
1470
16th to endNight
52%5%10%20%9%
1422
July1st to 15thNight
46%6%13%20%11%
1402
16th to endNight
54%7%11%18%7%1
1582
August1st to 15thNight
48%8%12%22%8%
1713
16th to endNight
39%6%13%22%16%
1863
September1st to 15thNight
38%5%12%25%16%
2078
16th to endNight
36%310%29%19%
2145
October1st to 15thNight
44%5%10%24%14%1
2258
16th to endNight
46%410%25%12%
2626
November1st to 15thNight
46%5%12%21%13%1
2667
16th to endNight
47%6%12%20%12%1
2913
December1st to 15thNight
52%411%21%9%
3053
16th to endNight
50%412%20%11%
3360

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
21%32%35%7%1
120
16th to endDay
23%32%34%8%
178
February1st to 15thDay
24%34%28%11%1
326
16th to endDay
21%28%35%13%1
341
March1st to 15thDay
25%27%30%13%2
390
16th to endDay
21%31%28%12%5%1
416
April1st to 15thDay
25%27%30%11%31
390
16th to endDay
28%18%31%13%5%1
379
May1st to 15thDay
27%23%29%13%4
408
16th to endDay
24%19%31%16%6%
545
June1st to 15thDay
23%14%30%23%7%
645
16th to endDay
27%15%27%21%8%
610
July1st to 15thDay
19%10%30%23%15%
441
16th to endDay
19%11%29%27%10%1
390
August1st to 15thDay
18%12%24%29%13%1
358
16th to endDay
15%9%25%31%14%4
396
September1st to 15thDay
18%8%28%31%10%2
375
16th to endDay
18%9%32%21%12%4
374
October1st to 15thDay
22%15%26%23%10%2
340
16th to endDay
24%22%33%15%3
336
November1st to 15thDay
22%28%20%20%5%1
325
16th to endDay
24%27%25%16%41
330
December1st to 15thDay
24%22%32%18%3
215
16th to endDay
32%31%25%10%
128
January1st to 15thNight
18%38%27%13%2
840
16th to endNight
20%37%28%11%2
896
February1st to 15thNight
20%36%28%11%2
824
16th to endNight
21%32%27%13%3
735
March1st to 15thNight
23%29%28%15%2
840
16th to endNight
18%28%29%17%5%
896
April1st to 15thNight
25%25%30%15%3
773
16th to endNight
26%20%25%20%6%
623
May1st to 15thNight
24%19%27%21%6%1
630
16th to endNight
25%19%23%23%7%
567
June1st to 15thNight
28%18%20%25%7%
420
16th to endNight
27%15%18%27%9%
406
July1st to 15thNight
23%12%18%31%12%1
370
16th to endNight
22%16%18%29%12%
447
August1st to 15thNight
23%10%16%33%14%1
574
16th to endNight
16%9%20%33%18%1
621
September1st to 15thNight
17%9%25%30%14%2
765
16th to endNight
18%12%25%26%14%3
777
October1st to 15thNight
22%16%25%22%11%1
780
16th to endNight
22%23%30%16%6%
832
November1st to 15thNight
20%27%22%20%7%1
820
16th to endNight
20%32%26%14%6%
893
December1st to 15thNight
26%31%25%13%3
900
16th to endNight
26%32%26%11%1
960
Page generated at 2019-06-24 20:41:28. Version ac04

Copyright 2019 A. Danko


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