Lawrence
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lawrence clear sky chart from 2005-11-05 to 2018-10-08.

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%
17288
21%
51211
13%
17241
45%
17241
32%
30693

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
30%
975
20%
2522
8%
970
38%
970
32%
1588
January16th to endNight
26%
1040
22%
2704
9%
1040
34%
1040
34%
1702
February1st to 15thNight
21%
955
14%
2483
5%
951
27%
951
24%
1743
February16th to endNight
24%
715
19%
2081
6%
715
33%
715
28%
1317
March1st to 15thNight
28%
585
21%
2145
12%
585
40%
585
25%
1241
March16th to endNight
24%
624
14%
2288
9%
624
32%
624
19%
1494
April1st to 15thNight
27%
584
20%
2024
12%
584
41%
584
28%
1175
April16th to endNight
27%
579
16%
1805
11%
579
36%
579
25%
1165
May1st to 15thNight
36%
585
18%
1755
15%
585
43%
585
29%
1111
May16th to endNight
42%
611
15%
1829
12%
609
46%
609
35%
1069
June1st to 15thNight
51%
585
20%
1586
12%
585
55%
585
43%
907
June16th to endNight
53%
585
20%
1633
11%
585
57%
585
52%
861
July1st to 15thNight
65%
555
18%
1665
15%
555
66%
555
43%
893
July16th to endNight
63%
612
21%
1738
21%
579
68%
579
44%
920
August1st to 15thNight
71%
575
23%
1717
27%
572
73%
572
42%
930
August16th to endNight
67%
621
25%
1947
27%
621
71%
621
40%
1043
September1st to 15thNight
57%
585
25%
2033
27%
585
61%
585
31%
1150
September16th to endNight
58%
582
25%
2145
23%
582
66%
582
35%
1116
October1st to 15thNight
40%
729
25%
2233
18%
729
45%
729
31%
1338
October16th to endNight
37%
768
28%
2304
15%
768
48%
768
38%
1257
November1st to 15thNight
36%
848
26%
2368
13%
848
46%
848
38%
1358
November16th to endNight
29%
975
23%
2668
9%
975
39%
975
35%
1601
December1st to 15thNight
26%
975
17%
2730
7%
975
35%
975
27%
1771
December16th to endNight
24%
1040
20%
2808
7%
1040
34%
1040
24%
1943

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
9%5%2417%23346%40%
51909
Night
8%5%1316%23345%44%
51406
Cloud CoverDay
11%6%25%42445%7%45%
51907
Night
10%5%24423446%50%
51406
TransparencyDay
37%6%13%25%15%2
51607
Night
33%5%12%26%18%3
51211
SeeingDay
13%6%26%29%19%4
7317
Night
13%7%31%33%13%1
17288

By Month

Percentage Cloud Cover SW (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
8%5%25%20%3234440%
1746
16th to endDay
8%8%3419%12345%38%
1872
February1st to 15thDay
10%7%35%18%3233436%
1710
16th to endDay
11%8%25%19%2333434%
1686
March1st to 15thDay
8%8%25%20%23445%34%
2145
16th to endDay
16%8%26%19%1323431%
2288
April1st to 15thDay
13%6%2419%2333435%
2253
16th to endDay
14%7%35%20%2433429%
2427
May1st to 15thDay
11%6%1420%23445%34%
2526
16th to endDay
10%5%2419%3445%6%32%
2638
June1st to 15thDay
6%31319%2345%7%41%
2701
16th to endDay
221318%3445%8%45%
2650
July1st to 15thDay
6%21313%8%445%7%41%
2535
16th to endDay
5%21319%3445%8%41%
2674
August1st to 15thDay
6%21413%3445%7%45%
2486
16th to endDay
7%41412%33447%45%
2607
September1st to 15thDay
11%6%2410%22346%44%
2255
16th to endDay
6%41312%235%5%7%47%
2145
October1st to 15thDay
12%5%1411%2234445%
1884
16th to endDay
9%31312%13335%52%
1920
November1st to 15thDay
8%41316%2233449%
1817
16th to endDay
12%41318%1222446%
1619
December1st to 15thDay
13%6%25%19%1333436%
1560
16th to endDay
10%8%36%19%23335%34%
1765
January1st to 15thNight
7%5%1420%2244442%
2522
16th to endNight
6%6%25%19%1333443%
2704
February1st to 15thNight
8%9%25%20%2333435%
2473
16th to endNight
11%5%25%18%2233439%
2081
March1st to 15thNight
8%6%2419%2323342%
2145
16th to endNight
15%6%1319%22345%34%
2288
April1st to 15thNight
8%5%2319%23335%42%
2024
16th to endNight
14%6%2419%22345%34%
1805
May1st to 15thNight
9%5%1318%22447%38%
1754
16th to endNight
8%31219%13449%41%
1827
June1st to 15thNight
42219%2335%6%47%
1586
16th to endNight
11217%12449%53%
1633
July1st to 15thNight
5%1212%8%245%7%47%
1755
16th to endNight
32318%3345%8%45%
1846
August1st to 15thNight
321212%235%6%9%51%
1727
16th to endNight
6%21211%23246%56%
1947
September1st to 15thNight
10%41311%235%36%47%
2033
16th to endNight
5%31311%24446%52%
2145
October1st to 15thNight
14%41311%2233447%
2233
16th to endNight
7%41311%12235%56%
2304
November1st to 15thNight
6%42216%23235%50%
2368
16th to endNight
10%41318%1223447%
2668
December1st to 15thNight
11%7%2419%1334438%
2730
16th to endNight
11%9%25%19%2223435%
2808

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
11%5%26%433345%47%
1746
16th to endDay
11%8%46%31335%6%44%
1872
February1st to 15thDay
12%8%5%6%433345%41%
1710
16th to endDay
12%9%26%5%2444442%
1686
March1st to 15thDay
11%9%36%5%2445%6%40%
2145
16th to endDay
20%9%36%424345%34%
2286
April1st to 15thDay
16%7%25%5%24345%41%
2253
16th to endDay
18%7%36%5%25%435%36%
2427
May1st to 15thDay
15%7%35%5%34446%38%
2526
16th to endDay
13%6%35%42446%8%39%
2638
June1st to 15thDay
7%424425%5%6%8%46%
2701
16th to endDay
5%213335%5%6%10%51%
2650
July1st to 15thDay
7%313435%5%6%9%48%
2535
16th to endDay
6%3244345%6%9%49%
2674
August1st to 15thDay
6%3145%346%7%8%48%
2486
16th to endDay
9%4245%3445%8%48%
2607
September1st to 15thDay
12%5%25%323447%47%
2255
16th to endDay
7%4244245%6%7%51%
2145
October1st to 15thDay
14%6%1442335%6%49%
1884
16th to endDay
12%313423346%54%
1920
November1st to 15thDay
9%5%23324346%55%
1817
16th to endDay
15%424313335%52%
1619
December1st to 15thDay
13%8%34433345%43%
1560
16th to endDay
13%8%47%5%24347%38%
1765
January1st to 15thNight
8%6%245%24445%51%
2522
16th to endNight
8%7%25%423345%51%
2704
February1st to 15thNight
10%10%36%5%34345%39%
2473
16th to endNight
11%6%25%434435%47%
2081
March1st to 15thNight
9%7%245%24345%49%
2145
16th to endNight
19%7%34334347%38%
2288
April1st to 15thNight
10%6%24424346%50%
2024
16th to endNight
17%6%24424345%43%
1805
May1st to 15thNight
11%6%2432346%8%44%
1754
16th to endNight
9%42342345%9%49%
1827
June1st to 15thNight
5%212335%5%5%9%55%
1586
16th to endNight
41231346%10%61%
1633
July1st to 15thNight
5%21342446%9%55%
1755
16th to endNight
5%2134345%6%10%53%
1846
August1st to 15thNight
32133245%8%10%54%
1727
16th to endNight
7%313423346%58%
1947
September1st to 15thNight
10%4233245%46%50%
2033
16th to endNight
6%31442445%6%56%
2145
October1st to 15thNight
15%414323345%50%
2233
16th to endNight
9%413322335%59%
2304
November1st to 15thNight
8%424323336%57%
2368
16th to endNight
13%5%23213245%53%
2668
December1st to 15thNight
12%7%34424345%46%
2730
16th to endNight
14%10%36%424346%40%
2808

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
38%5%13%25%16%1
1747
16th to endDay
40%5%15%25%12%1
1872
February1st to 15thDay
45%5%16%22%8%1
1711
16th to endDay
44%412%23%12%2
1686
March1st to 15thDay
42%5%12%23%12%2
2145
16th to endDay
52%5%12%20%8%1
2288
April1st to 15thDay
44%5%11%22%15%
2253
16th to endDay
49%5%11%21%11%
2427
May1st to 15thDay
46%7%10%22%12%
2526
16th to endDay
41%8%15%21%11%1
2642
June1st to 15thDay
31%8%14%27%15%1
2701
16th to endDay
26%8%16%29%17%1
2650
July1st to 15thDay
30%7%16%26%14%3
2396
16th to endDay
27%7%15%31%15%1
2519
August1st to 15thDay
31%8%14%27%16%2
2472
16th to endDay
33%7%12%25%15%5%
2607
September1st to 15thDay
36%5%11%23%17%5%
2255
16th to endDay
30%6%11%28%20%2
2145
October1st to 15thDay
35%410%24%19%4
1884
16th to endDay
31%412%26%21%4
1920
November1st to 15thDay
30%5%11%26%20%5%
1817
16th to endDay
35%39%29%20%
1619
December1st to 15thDay
41%5%15%25%10%
1560
16th to endDay
47%412%21%12%2
1765
January1st to 15thNight
34%5%15%25%17%1
2522
16th to endNight
35%413%28%16%2
2704
February1st to 15thNight
45%5%13%22%11%1
2483
16th to endNight
39%411%21%18%3
2081
March1st to 15thNight
36%5%10%24%18%4
2145
16th to endNight
46%5%13%21%11%1
2288
April1st to 15thNight
35%411%26%19%2
2024
16th to endNight
42%410%24%15%1
1805
May1st to 15thNight
37%6%13%24%16%1
1755
16th to endNight
30%7%19%26%14%1
1829
June1st to 15thNight
24%7%15%33%15%3
1586
16th to endNight
17%7%14%35%22%3
1633
July1st to 15thNight
23%7%15%32%16%4
1665
16th to endNight
23%5%14%33%20%2
1738
August1st to 15thNight
21%9%15%32%17%3
1717
16th to endNight
26%5%10%28%22%6%
1947
September1st to 15thNight
32%6%10%23%20%6%
2033
16th to endNight
26%6%10%27%24%3
2145
October1st to 15thNight
35%48%22%22%6%
2233
16th to endNight
28%39%29%25%4
2304
November1st to 15thNight
29%411%25%22%7%
2368
16th to endNight
32%39%31%19%2
2668
December1st to 15thNight
40%414%26%13%
2730
16th to endNight
46%412%21%12%2
2808

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
20%15%37%20%5%
135
16th to endDay
16%6%46%24%4
144
February1st to 15thDay
14%19%45%17%2
135
16th to endDay
20%19%35%17%7%
120
March1st to 15thDay
16%18%44%17%3
135
16th to endDay
29%15%35%15%3
144
April1st to 15thDay
21%13%33%24%6%
252
16th to endDay
23%10%33%20%10%
439
May1st to 15thDay
18%9%33%25%12%1
543
16th to endDay
16%6%29%27%16%4
597
June1st to 15thDay
8%323%37%20%5%
570
16th to endDay
6%428%38%18%3
570
July1st to 15thDay
9%115%34%29%10%
550
16th to endDay
7%112%35%37%5%
595
August1st to 15thDay
7%111%39%35%5%
549
16th to endDay
11%217%32%29%6%
519
September1st to 15thDay
12%115%33%27%8%
290
16th to endDay
11%320%41%15%7%
180
October1st to 15thDay
15%6%36%24%9%6%
157
16th to endDay
9%12%40%26%10%
144
November1st to 15thDay
14%5%29%30%11%7%
135
16th to endDay
24%16%34%15%8%
135
December1st to 15thDay
12%15%47%17%32
135
16th to endDay
20%18%38%20%2
144
January1st to 15thNight
12%12%38%29%6%
975
16th to endNight
12%10%42%29%4
1040
February1st to 15thNight
16%10%40%28%3
955
16th to endNight
16%10%40%26%5%
715
March1st to 15thNight
13%11%38%29%7%
585
16th to endNight
22%9%38%24%4
624
April1st to 15thNight
14%12%37%30%5%
584
16th to endNight
19%8%33%28%8%
579
May1st to 15thNight
15%5%32%32%11%1
585
16th to endNight
10%431%34%16%1
611
June1st to 15thNight
6%224%47%18%1
585
16th to endNight
4228%47%16%
585
July1st to 15thNight
6%114%45%28%3
555
16th to endNight
5%11%50%30%1
612
August1st to 15thNight
5%10%46%36%1
575
16th to endNight
9%114%38%33%3
621
September1st to 15thNight
12%217%39%24%3
585
16th to endNight
7%320%41%23%3
582
October1st to 15thNight
18%428%29%17%1
729
16th to endNight
13%8%36%29%11%
768
November1st to 15thNight
10%11%33%31%13%
848
16th to endNight
16%10%37%28%6%
975
December1st to 15thNight
16%12%36%28%5%
975
16th to endNight
19%9%36%28%5%
1040
Page generated at 2018-10-09 09:39:09. Version ac04

Copyright 2018 A. Danko


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