Morrisburg
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Morrisburg clear sky chart from 2005-11-05 to 2017-08-12.

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
27%
14544
13%
46489
8%
14513
33%
14513
16%
33459

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
13%
720
6%
2506
2%
716
17%
716
6%
2061
January16th to endNight
17%
768
9%
2652
5%
768
24%
768
9%
2059
February1st to 15thNight
13%
704
9%
2287
3%
701
20%
701
8%
1846
February16th to endNight
18%
631
12%
1925
5%
631
28%
631
11%
1485
March1st to 15thNight
19%
720
13%
2121
7%
720
26%
720
14%
1595
March16th to endNight
27%
768
19%
2019
8%
768
35%
768
20%
1440
April1st to 15thNight
22%
718
16%
1796
6%
718
28%
718
20%
1337
April16th to endNight
25%
667
17%
1747
6%
667
33%
667
23%
1220
May1st to 15thNight
31%
360
17%
1440
15%
360
40%
360
16%
925
May16th to endNight
32%
374
14%
1497
10%
374
43%
374
18%
933
June1st to 15thNight
34%
360
10%
1440
10%
360
41%
360
14%
992
June16th to endNight
38%
360
9%
1440
12%
360
44%
360
19%
880
July1st to 15thNight
47%
340
15%
1360
19%
340
55%
340
27%
743
July16th to endNight
50%
376
14%
1418
14%
354
55%
354
26%
796
August1st to 15thNight
47%
416
14%
1465
12%
414
51%
414
23%
925
August16th to endNight
47%
673
20%
1723
10%
673
52%
673
37%
1082
September1st to 15thNight
45%
660
16%
1650
7%
660
48%
660
29%
1130
September16th to endNight
45%
657
21%
1785
14%
657
49%
657
30%
1159
October1st to 15thNight
31%
660
18%
1980
12%
660
40%
660
19%
1379
October16th to endNight
24%
704
10%
2212
5%
704
31%
704
12%
1684
November1st to 15thNight
25%
700
16%
2298
12%
700
32%
700
16%
1616
November16th to endNight
20%
720
11%
2520
8%
720
27%
720
10%
1911
December1st to 15thNight
14%
720
6%
2520
2%
720
18%
720
7%
2038
December16th to endNight
12%
768
7%
2688
3%
768
17%
768
6%
2223

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%9%36%5%34446%32%
47496
Night
19%10%47%5%34446%31%
46658
Cloud CoverDay
18%9%36%5%34446%31%
47505
Night
19%10%47%5%34445%30%
46664
TransparencyDay
53%311%20%10%1
47183
Night
55%311%19%9%1
46489
SeeingDay
25%12%28%20%9%3
5382
Night
26%12%27%23%9%
14545

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
23%17%5%8%7%35%33418%
1432
16th to endDay
14%16%5%10%7%44445%22%
1572
February1st to 15thDay
16%14%6%9%8%5%5%445%20%
1575
16th to endDay
19%16%48%8%2333325%
1548
March1st to 15thDay
19%13%48%7%35%33327%
1828
16th to endDay
19%9%25%423335%39%
2205
April1st to 15thDay
24%10%45%5%2333432%
2152
16th to endDay
20%8%35%42345%5%36%
2223
May1st to 15thDay
19%7%35%5%24447%34%
2511
16th to endDay
17%6%26%5%25%45%7%36%
2618
June1st to 15thDay
23%6%345%345%5%6%31%
2520
16th to endDay
19%5%25%5%35%5%6%7%32%
2520
July1st to 15thDay
14%5%25%5%35%46%8%39%
2520
16th to endDay
13%5%15%5%36%6%7%8%36%
2654
August1st to 15thDay
13%6%25%6%36%6%6%7%34%
2398
16th to endDay
12%415%5%26%5%5%7%42%
2116
September1st to 15thDay
18%5%145%3445%7%40%
1980
16th to endDay
17%5%24423447%43%
1842
October1st to 15thDay
20%7%35%5%345%47%33%
1650
16th to endDay
28%10%47%5%34225%23%
1659
November1st to 15thDay
15%8%46%5%35%5%46%32%
1557
16th to endDay
23%13%37%6%23335%24%
1440
December1st to 15thDay
25%17%5%8%6%24435%16%
1440
16th to endDay
26%15%5%8%6%2433319%
1536
January1st to 15thNight
20%18%6%10%6%3443417%
2506
16th to endNight
14%17%6%8%7%34445%23%
2652
February1st to 15thNight
15%14%7%13%8%3434420%
2285
16th to endNight
18%13%5%8%6%34445%26%
1925
March1st to 15thNight
22%12%47%5%3323430%
2108
16th to endNight
18%10%35%5%2334438%
2019
April1st to 15thNight
24%8%35%5%23345%34%
1796
16th to endNight
19%8%26%423346%38%
1747
May1st to 15thNight
20%8%35%5%24446%34%
1440
16th to endNight
17%6%25%335%45%7%38%
1495
June1st to 15thNight
22%5%26%6%46%45%7%28%
1440
16th to endNight
17%6%244345%6%8%36%
1440
July1st to 15thNight
12%224335%5%6%10%44%
1440
16th to endNight
10%414425%6%7%8%42%
1514
August1st to 15thNight
12%6%25%5%245%6%9%38%
1475
16th to endNight
13%31441446%6%48%
1723
September1st to 15thNight
18%5%245%24446%42%
1650
16th to endNight
15%4244235%45%46%
1785
October1st to 15thNight
19%9%35%434446%35%
1980
16th to endNight
28%9%36%5%23446%25%
2212
November1st to 15thNight
20%9%36%5%34445%33%
2298
16th to endNight
22%12%5%8%5%23435%24%
2520
December1st to 15thNight
23%17%5%8%5%24435%19%
2520
16th to endNight
25%17%5%8%5%3433318%
2688

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
22%16%5%9%8%35%42318%
1432
16th to endDay
14%17%5%10%7%35%336%21%
1572
February1st to 15thDay
16%14%7%10%8%4444419%
1575
16th to endDay
18%16%5%8%7%3333424%
1548
March1st to 15thDay
20%12%5%9%6%25%33326%
1838
16th to endDay
19%9%35%424335%39%
2204
April1st to 15thDay
24%10%35%5%2333432%
2152
16th to endDay
20%8%34423445%36%
2223
May1st to 15thDay
19%7%36%5%245%46%34%
2511
16th to endDay
17%6%25%5%35%5%5%7%35%
2618
June1st to 15thDay
24%6%34425%5%46%31%
2520
16th to endDay
19%6%25%5%36%5%6%7%32%
2520
July1st to 15thDay
13%5%345%35%46%8%38%
2520
16th to endDay
12%5%25%5%45%7%6%8%36%
2654
August1st to 15thDay
13%6%25%6%36%5%6%7%34%
2398
16th to endDay
12%5%146%25%5%6%7%42%
2116
September1st to 15thDay
18%415%5%24347%39%
1980
16th to endDay
16%6%2442345%6%42%
1842
October1st to 15thDay
19%8%26%5%34446%33%
1650
16th to endDay
27%11%37%6%24335%23%
1659
November1st to 15thDay
15%8%46%6%35%45%6%31%
1557
16th to endDay
22%14%48%5%2424425%
1440
December1st to 15thDay
24%18%5%8%5%2433416%
1440
16th to endDay
26%16%5%8%5%3434318%
1536
January1st to 15thNight
20%18%6%11%5%3434416%
2506
16th to endNight
15%17%6%9%7%44335%22%
2652
February1st to 15thNight
16%14%7%13%8%3434419%
2278
16th to endNight
18%13%5%8%7%3443425%
1925
March1st to 15thNight
21%13%5%7%433325%30%
2121
16th to endNight
18%10%36%42333438%
2019
April1st to 15thNight
23%10%34433335%33%
1796
16th to endNight
20%8%25%423446%37%
1747
May1st to 15thNight
19%8%35%42445%6%35%
1440
16th to endNight
17%5%245%345%6%6%37%
1495
June1st to 15thNight
23%6%26%5%35%45%7%29%
1440
16th to endNight
17%6%25%3345%5%9%36%
1440
July1st to 15thNight
12%3144345%7%9%43%
1440
16th to endNight
10%424425%5%8%8%42%
1514
August1st to 15thNight
12%7%35%6%245%6%8%37%
1475
16th to endNight
13%41442345%7%48%
1723
September1st to 15thNight
17%5%24424445%43%
1650
16th to endNight
15%4245%2345%6%45%
1785
October1st to 15thNight
20%9%35%424447%34%
1980
16th to endNight
28%10%27%433445%25%
2212
November1st to 15thNight
20%10%36%424445%32%
2298
16th to endNight
22%12%5%8%5%2344425%
2520
December1st to 15thNight
23%17%5%7%6%25%33418%
2520
16th to endNight
25%17%6%8%6%3433317%
2688

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
72%37%10%5%1
1433
16th to endDay
65%312%11%6%
1572
February1st to 15thDay
68%27%16%3
1577
16th to endDay
63%210%12%8%1
1548
March1st to 15thDay
63%211%13%7%1
1838
16th to endDay
49%28%18%15%5%
2205
April1st to 15thDay
56%26%19%12%2
2152
16th to endDay
49%27%21%15%4
2223
May1st to 15thDay
48%49%21%14%1
2511
16th to endDay
46%412%21%13%1
2622
June1st to 15thDay
51%5%10%21%10%
2520
16th to endDay
48%5%11%22%10%
2520
July1st to 15thDay
39%412%30%12%
2371
16th to endDay
42%6%16%24%9%
2487
August1st to 15thDay
45%5%16%22%9%
2384
16th to endDay
38%415%29%12%
2116
September1st to 15thDay
43%310%28%13%
1980
16th to endDay
41%310%33%11%
1842
October1st to 15thDay
51%212%22%9%
1650
16th to endDay
64%311%13%6%
1659
November1st to 15thDay
52%413%20%8%
1557
16th to endDay
64%210%14%7%
1440
December1st to 15thDay
71%39%12%2
1440
16th to endDay
71%39%10%4
1536
January1st to 15thNight
71%310%9%4
2506
16th to endNight
65%29%16%5%
2652
February1st to 15thNight
69%28%14%3
2287
16th to endNight
63%29%16%8%
1925
March1st to 15thNight
60%210%18%7%
2121
16th to endNight
51%28%19%14%3
2019
April1st to 15thNight
54%27%20%13%
1796
16th to endNight
48%28%20%15%3
1747
May1st to 15thNight
49%28%18%15%3
1440
16th to endNight
44%413%21%13%2
1497
June1st to 15thNight
53%412%17%10%
1440
16th to endNight
43%415%20%14%
1440
July1st to 15thNight
33%5%14%30%15%
1360
16th to endNight
35%5%17%24%16%
1418
August1st to 15thNight
42%5%17%21%12%
1465
16th to endNight
34%413%32%13%
1723
September1st to 15thNight
43%411%28%12%
1650
16th to endNight
40%310%32%12%
1785
October1st to 15thNight
50%410%23%10%
1980
16th to endNight
61%313%16%4
2212
November1st to 15thNight
53%413%16%10%1
2298
16th to endNight
62%411%15%5%1
2520
December1st to 15thNight
69%312%12%2
2520
16th to endNight
72%39%10%3
2688

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%20%30%13%11%
60
16th to endDay
34%15%31%14%4
70
February1st to 15thDay
38%25%28%6%
90
16th to endDay
35%14%28%19%1
207
March1st to 15thDay
28%16%31%16%6%
270
16th to endDay
28%15%30%14%7%2
288
April1st to 15thDay
35%16%27%14%5%1
270
16th to endDay
25%16%27%15%11%4
270
May1st to 15thDay
30%10%27%18%11%2
288
16th to endDay
21%18%29%19%9%1
331
June1st to 15thDay
31%10%27%20%8%1
315
16th to endDay
23%10%31%21%10%1
315
July1st to 15thDay
18%5%29%27%14%4
305
16th to endDay
16%6%30%29%12%4
326
August1st to 15thDay
18%5%26%28%14%5%
297
16th to endDay
14%5%29%29%10%11%
268
September1st to 15thDay
21%5%26%22%10%13%
255
16th to endDay
19%10%27%20%15%7%
254
October1st to 15thDay
25%12%25%16%16%3
255
16th to endDay
39%13%22%17%6%
253
November1st to 15thDay
19%13%35%19%9%2
211
16th to endDay
41%8%26%18%5%
60
December1st to 15thDay
31%20%31%11%5%
60
16th to endDay
51%21%18%6%1
64
January1st to 15thNight
33%17%28%16%4
720
16th to endNight
26%17%30%20%5%
768
February1st to 15thNight
25%19%32%19%2
704
16th to endNight
26%17%31%20%4
631
March1st to 15thNight
31%16%28%20%4
720
16th to endNight
26%13%26%23%8%
768
April1st to 15thNight
30%12%28%23%4
718
16th to endNight
27%13%29%20%8%
667
May1st to 15thNight
25%9%28%25%8%1
360
16th to endNight
20%8%33%27%9%
375
June1st to 15thNight
25%10%23%29%10%
360
16th to endNight
19%6%28%30%12%1
360
July1st to 15thNight
12%5%26%39%15%
340
16th to endNight
12%5%27%38%14%1
376
August1st to 15thNight
17%224%35%18%1
416
16th to endNight
14%426%32%20%2
673
September1st to 15thNight
20%6%23%30%17%1
660
16th to endNight
18%8%25%26%20%1
657
October1st to 15thNight
27%10%26%20%14%
660
16th to endNight
35%14%20%23%6%
704
November1st to 15thNight
28%12%28%20%10%
700
16th to endNight
31%15%24%19%8%
720
December1st to 15thNight
35%18%25%16%4
720
16th to endNight
36%15%27%16%2
768
Page generated at 2017-08-13 14:16:15. Version ac04

Copyright 2017 A. Danko


Morrisburg Clear Sky Chart | Charts Home