Lockport
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lockport clear sky chart from 2005-11-05 to 2017-12-20.

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
38%
16352
18%
48027
11%
16310
44%
16310
24%
32153

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
20%
900
13%
2506
4%
895
29%
895
17%
1830
January16th to endNight
21%
960
13%
2652
5%
960
28%
960
16%
2025
February1st to 15thNight
22%
788
13%
2199
4%
788
29%
788
18%
1587
February16th to endNight
26%
631
18%
1893
8%
631
35%
631
18%
1338
March1st to 15thNight
26%
720
13%
2160
8%
720
30%
720
17%
1546
March16th to endNight
30%
627
15%
2013
10%
627
37%
627
18%
1403
April1st to 15thNight
30%
539
15%
1797
11%
539
39%
539
21%
1203
April16th to endNight
33%
540
18%
1737
10%
540
42%
540
21%
1171
May1st to 15thNight
38%
540
15%
1608
9%
540
44%
540
23%
1105
May16th to endNight
50%
562
17%
1497
10%
561
55%
561
32%
978
June1st to 15thNight
52%
540
17%
1440
10%
540
56%
540
35%
904
June16th to endNight
49%
540
17%
1440
10%
540
54%
540
32%
940
July1st to 15thNight
61%
510
17%
1360
11%
510
64%
510
38%
828
July16th to endNight
71%
564
22%
1417
18%
531
74%
531
45%
829
August1st to 15thNight
78%
539
22%
1584
23%
536
79%
536
43%
875
August16th to endNight
67%
573
21%
1910
22%
573
71%
573
34%
1067
September1st to 15thNight
65%
546
28%
1806
29%
546
70%
546
37%
978
September16th to endNight
60%
717
27%
1980
20%
717
64%
717
36%
1185
October1st to 15thNight
48%
720
26%
2066
19%
720
53%
720
32%
1249
October16th to endNight
30%
768
20%
2442
13%
768
40%
768
22%
1590
November1st to 15thNight
30%
760
23%
2471
16%
760
41%
760
23%
1547
November16th to endNight
25%
809
19%
2564
10%
809
35%
809
20%
1704
December1st to 15thNight
22%
975
13%
2730
4%
975
29%
975
17%
2018
December16th to endNight
17%
984
11%
2755
3%
984
23%
984
11%
2253

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%8%36%5%3445%7%36%
48822
Night
14%7%35%424446%40%
48196
Cloud CoverDay
14%7%36%5%35%45%7%36%
48831
Night
14%7%35%424446%40%
48201
TransparencyDay
45%6%12%21%12%1
48508
Night
44%5%11%22%13%2
48028
SeeingDay
15%7%28%26%15%6%
6266
Night
17%8%29%30%12%1
16356

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%14%48%6%35%346%25%
1432
16th to endDay
14%15%6%8%7%24445%25%
1571
February1st to 15thDay
16%13%6%7%5%35%446%26%
1662
16th to endDay
17%10%48%6%23346%32%
1580
March1st to 15thDay
17%13%46%5%25%345%29%
1790
16th to endDay
18%9%36%6%35%446%30%
2221
April1st to 15thDay
18%10%46%42445%6%32%
2151
16th to endDay
19%8%25%43445%6%35%
2223
May1st to 15thDay
19%8%35%5%35%5%6%7%28%
2340
16th to endDay
13%5%35%435%5%5%7%39%
2617
June1st to 15thDay
11%5%25%4345%5%7%44%
2520
16th to endDay
9%5%25%6%45%6%7%9%36%
2520
July1st to 15thDay
7%4345%36%5%6%9%44%
2520
16th to endDay
6%425%5%45%6%7%10%40%
2655
August1st to 15thDay
7%426%445%5%7%9%43%
2364
16th to endDay
9%425%5%35%6%6%9%42%
2292
September1st to 15thDay
12%324324447%48%
2142
16th to endDay
8%6%245%25%6%5%8%46%
1980
October1st to 15thDay
17%5%24333447%42%
1893
16th to endDay
18%7%36%5%23347%37%
1782
November1st to 15thDay
15%7%35%423446%40%
1717
16th to endDay
18%8%47%423345%37%
1722
December1st to 15thDay
17%12%47%5%35%436%29%
1560
16th to endDay
21%16%5%7%5%34335%22%
1568
January1st to 15thNight
17%11%46%5%33445%32%
2506
16th to endNight
14%12%6%9%7%34345%28%
2652
February1st to 15thNight
16%12%5%6%5%23336%34%
2197
16th to endNight
16%10%47%5%33346%34%
1893
March1st to 15thNight
16%11%46%5%2443435%
2147
16th to endNight
16%7%46%5%3446%6%34%
2013
April1st to 15thNight
17%8%45%434347%36%
1797
16th to endNight
18%7%25%434346%38%
1737
May1st to 15thNight
17%6%25%5%2445%9%35%
1608
16th to endNight
10%4234345%6%9%44%
1496
June1st to 15thNight
10%4245%23446%51%
1440
16th to endNight
9%5%244345%6%9%41%
1440
July1st to 15thNight
5%5%145%245%5%8%50%
1440
16th to endNight
431442448%9%51%
1513
August1st to 15thNight
332443346%9%54%
1593
16th to endNight
9%21332445%8%51%
1910
September1st to 15thNight
10%313313346%55%
1806
16th to endNight
7%42442446%7%50%
1980
October1st to 15thNight
14%424313337%50%
2066
16th to endNight
19%7%25%313245%41%
2442
November1st to 15thNight
14%7%25%423345%45%
2471
16th to endNight
18%7%35%5%23336%38%
2564
December1st to 15thNight
20%10%47%433445%32%
2730
16th to endNight
24%15%5%9%5%3433322%
2755

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%14%47%6%35%45%6%25%
1432
16th to endDay
14%14%7%9%6%25%445%24%
1571
February1st to 15thDay
15%14%6%7%6%35%435%26%
1662
16th to endDay
16%9%5%8%6%23446%32%
1580
March1st to 15thDay
17%13%46%6%36%35%5%29%
1800
16th to endDay
18%8%46%6%35%446%30%
2220
April1st to 15thDay
18%10%46%5%2445%6%32%
2151
16th to endDay
20%8%25%5%24446%35%
2223
May1st to 15thDay
19%8%36%5%35%5%6%7%29%
2340
16th to endDay
13%6%25%5%35%5%5%7%39%
2617
June1st to 15thDay
11%5%25%5%25%5%5%7%44%
2520
16th to endDay
10%425%6%46%6%7%9%36%
2520
July1st to 15thDay
7%325%5%35%5%5%9%44%
2520
16th to endDay
6%425%5%35%5%7%10%41%
2655
August1st to 15thDay
7%425%6%345%7%9%43%
2364
16th to endDay
9%425%5%35%6%6%9%42%
2292
September1st to 15thDay
13%324334447%48%
2142
16th to endDay
8%425%4246%48%45%
1980
October1st to 15thDay
16%7%24433446%42%
1893
16th to endDay
18%7%35%5%23446%37%
1782
November1st to 15thDay
15%7%36%414347%40%
1717
16th to endDay
18%8%47%423345%37%
1722
December1st to 15thDay
17%12%47%6%35%435%29%
1560
16th to endDay
21%15%5%7%5%24335%22%
1568
January1st to 15thNight
17%11%46%5%34345%32%
2506
16th to endNight
14%12%6%8%7%34345%28%
2652
February1st to 15thNight
15%12%46%5%23435%34%
2190
16th to endNight
16%10%46%5%34346%34%
1893
March1st to 15thNight
17%10%5%6%5%25%33435%
2160
16th to endNight
16%7%46%5%3445%6%34%
2013
April1st to 15thNight
17%7%46%43335%7%37%
1797
16th to endNight
18%6%35%434346%38%
1737
May1st to 15thNight
18%6%25%5%25%35%9%35%
1607
16th to endNight
10%3145%35%5%6%9%43%
1496
June1st to 15thNight
10%4245%24446%50%
1440
16th to endNight
10%425%435%5%6%10%40%
1440
July1st to 15thNight
5%5%144345%49%50%
1440
16th to endNight
331343448%9%52%
1513
August1st to 15thNight
431442446%9%54%
1593
16th to endNight
9%31332445%8%51%
1910
September1st to 15thNight
10%323323347%55%
1806
16th to endNight
7%424425%46%7%49%
1980
October1st to 15thNight
13%415%323347%49%
2066
16th to endNight
20%7%25%313345%41%
2442
November1st to 15thNight
14%7%25%423346%45%
2471
16th to endNight
18%7%35%5%23346%38%
2564
December1st to 15thNight
19%10%47%433445%32%
2730
16th to endNight
23%15%5%8%5%3433322%
2755

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
59%413%12%9%
1433
16th to endDay
60%5%11%15%6%
1571
February1st to 15thDay
59%5%10%15%8%1
1664
16th to endDay
53%6%12%20%5%1
1580
March1st to 15thDay
56%5%11%18%6%
1800
16th to endDay
53%6%13%20%5%
2221
April1st to 15thDay
52%5%9%20%11%
2151
16th to endDay
48%6%13%16%11%3
2223
May1st to 15thDay
51%7%11%21%6%
2340
16th to endDay
42%7%12%20%15%2
2621
June1st to 15thDay
37%7%10%24%18%1
2520
16th to endDay
40%9%12%20%14%2
2520
July1st to 15thDay
36%7%13%24%15%2
2371
16th to endDay
35%9%16%22%13%2
2488
August1st to 15thDay
34%8%14%25%15%1
2349
16th to endDay
36%8%13%23%16%3
2292
September1st to 15thDay
34%6%10%24%19%4
2142
16th to endDay
34%6%10%27%19%2
1980
October1st to 15thDay
41%5%11%25%13%2
1893
16th to endDay
46%5%12%22%11%1
1782
November1st to 15thDay
43%5%12%21%14%2
1717
16th to endDay
49%412%25%8%
1722
December1st to 15thDay
56%5%12%18%7%
1560
16th to endDay
65%5%10%11%6%
1568
January1st to 15thNight
53%412%18%10%
2506
16th to endNight
57%413%16%8%
2652
February1st to 15thNight
52%411%20%9%1
2199
16th to endNight
51%411%21%9%1
1893
March1st to 15thNight
52%5%11%17%10%2
2160
16th to endNight
49%6%13%19%9%1
2013
April1st to 15thNight
47%411%20%14%1
1797
16th to endNight
46%5%10%20%12%4
1737
May1st to 15thNight
45%6%13%23%10%
1608
16th to endNight
34%8%14%19%18%2
1498
June1st to 15thNight
34%6%10%27%18%3
1440
16th to endNight
36%7%13%22%18%2
1440
July1st to 15thNight
30%6%13%26%19%3
1360
16th to endNight
25%6%17%27%18%4
1417
August1st to 15thNight
24%6%16%30%19%2
1584
16th to endNight
29%6%12%26%19%4
1910
September1st to 15thNight
28%49%27%26%3
1806
16th to endNight
31%6%10%28%20%3
1980
October1st to 15thNight
34%410%26%20%2
2066
16th to endNight
44%410%24%14%1
2442
November1st to 15thNight
42%38%23%17%3
2471
16th to endNight
47%313%24%11%
2564
December1st to 15thNight
54%410%19%9%
2730
16th to endNight
67%49%13%4
2755

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%10%34%24%5%
90
16th to endDay
16%10%44%20%7%
96
February1st to 15thDay
16%26%42%13%1
90
16th to endDay
17%13%41%16%9%1
81
March1st to 15thDay
35%13%32%15%3
90
16th to endDay
30%9%28%20%10%1
245
April1st to 15thDay
21%13%28%23%11%1
270
16th to endDay
21%11%28%24%10%3
270
May1st to 15thDay
21%9%31%21%11%4
297
16th to endDay
15%9%35%23%13%3
517
June1st to 15thDay
11%7%30%31%14%4
495
16th to endDay
12%7%34%27%13%4
495
July1st to 15thDay
9%5%28%27%18%10%
475
16th to endDay
7%226%29%22%11%
515
August1st to 15thDay
6%117%35%23%15%
394
16th to endDay
9%314%31%27%13%
332
September1st to 15thDay
9%417%33%26%7%
315
16th to endDay
8%317%30%31%8%
314
October1st to 15thDay
20%5%25%28%17%3
228
16th to endDay
23%11%34%24%6%
144
November1st to 15thDay
18%6%31%24%11%6%
135
16th to endDay
25%11%40%14%8%
135
December1st to 15thDay
15%23%38%17%31
135
16th to endDay
28%20%43%5%1
108
January1st to 15thNight
20%14%37%20%5%
900
16th to endNight
19%14%33%29%2
960
February1st to 15thNight
22%10%36%25%4
791
16th to endNight
20%12%34%26%6%
631
March1st to 15thNight
21%13%35%23%5%
720
16th to endNight
20%9%34%26%8%
627
April1st to 15thNight
19%12%32%27%7%
539
16th to endNight
22%7%33%25%10%
540
May1st to 15thNight
20%5%31%30%11%
540
16th to endNight
11%427%38%17%
563
June1st to 15thNight
12%226%45%13%
540
16th to endNight
10%328%37%19%
540
July1st to 15thNight
8%220%40%27%1
510
16th to endNight
5%115%46%28%3
564
August1st to 15thNight
47%51%30%4
539
16th to endNight
10%114%36%33%3
573
September1st to 15thNight
11%215%35%29%5%
546
16th to endNight
9%5%18%34%27%3
717
October1st to 15thNight
16%6%24%33%17%1
720
16th to endNight
22%12%30%24%9%
768
November1st to 15thNight
17%10%36%23%10%1
760
16th to endNight
21%12%35%22%7%
809
December1st to 15thNight
26%10%34%23%5%
975
16th to endNight
30%10%33%20%3
984
Page generated at 2017-12-21 06:04:49. Version ac04

Copyright 2017 A. Danko


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