Litchfield High School
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Litchfield High School clear sky chart from 2005-11-05 to 2017-09-23.

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%
16156
17%
46694
9%
16109
45%
16109
26%
30779

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
31%
900
13%
2588
7%
895
37%
895
19%
1837
January16th to endNight
26%
960
13%
2505
4%
960
32%
960
19%
1846
February1st to 15thNight
33%
879
13%
2288
4%
875
39%
875
23%
1616
February16th to endNight
31%
787
15%
2049
5%
787
39%
787
24%
1436
March1st to 15thNight
35%
540
15%
1980
10%
540
41%
540
20%
1282
March16th to endNight
35%
576
15%
2112
13%
576
42%
576
17%
1426
April1st to 15thNight
33%
539
19%
1814
14%
539
43%
539
23%
1170
April16th to endNight
30%
540
17%
1620
12%
540
39%
540
19%
1153
May1st to 15thNight
32%
540
14%
1536
7%
540
37%
540
24%
1062
May16th to endNight
42%
563
15%
1498
5%
561
47%
561
31%
957
June1st to 15thNight
47%
540
14%
1371
4%
540
51%
540
38%
853
June16th to endNight
56%
540
17%
1260
6%
540
59%
540
47%
775
July1st to 15thNight
59%
510
17%
1210
7%
510
62%
510
51%
707
July16th to endNight
66%
564
21%
1477
12%
531
68%
531
47%
797
August1st to 15thNight
66%
539
22%
1610
19%
536
69%
536
38%
913
August16th to endNight
59%
573
22%
1756
19%
573
67%
573
40%
964
September1st to 15thNight
59%
540
24%
1806
22%
540
67%
540
38%
935
September16th to endNight
43%
530
23%
1917
16%
530
55%
530
31%
1055
October1st to 15thNight
36%
660
24%
1980
14%
660
44%
660
31%
1189
October16th to endNight
33%
704
17%
2112
8%
704
40%
704
22%
1410
November1st to 15thNight
35%
872
20%
2426
10%
872
43%
872
27%
1584
November16th to endNight
30%
900
16%
2520
9%
900
36%
900
21%
1754
December1st to 15thNight
27%
900
11%
2520
4%
900
34%
900
17%
1891
December16th to endNight
23%
960
12%
2739
3%
960
31%
960
12%
2167

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
13%7%36%5%3445%7%37%
48205
Night
12%7%35%5%3445%7%41%
46859
Cloud CoverDay
13%7%36%5%3445%7%37%
48216
Night
12%7%35%5%2445%7%41%
46863
Cloud CoverDay
13%7%36%5%3445%7%37%
48214
Night
12%7%35%5%2445%6%41%
46863
TransparencyDay
44%6%14%23%9%
47889
Night
42%5%13%24%11%1
46694
SeeingDay
16%7%28%28%15%3
6156
Night
15%7%31%32%12%1
16157

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
9%11%5%9%6%46%5%5%7%26%
1343
16th to endDay
7%14%6%9%6%5%7%5%5%7%25%
1716
February1st to 15thDay
7%11%5%9%6%36%5%6%7%29%
1575
16th to endDay
9%9%5%9%9%46%46%6%28%
1434
March1st to 15thDay
13%11%5%7%6%25%35%7%32%
1969
16th to endDay
16%8%47%6%35%447%30%
2112
April1st to 15thDay
17%8%35%5%2345%5%38%
2133
16th to endDay
24%11%35%5%23335%29%
2337
May1st to 15thDay
20%7%36%5%345%46%32%
2415
16th to endDay
14%6%25%6%25%6%6%8%35%
2617
June1st to 15thDay
14%7%245%345%6%8%36%
2586
16th to endDay
9%414435%5%6%9%45%
2700
July1st to 15thDay
7%3123245%6%8%53%
2676
16th to endDay
5%3134245%7%10%50%
2587
August1st to 15thDay
9%6%25%5%35%5%6%8%41%
2340
16th to endDay
12%42432345%8%47%
2445
September1st to 15thDay
10%32442445%8%48%
2153
16th to endDay
15%5%25%314446%45%
1868
October1st to 15thDay
16%7%25%424337%43%
1650
16th to endDay
18%9%45%42335%6%36%
1760
November1st to 15thDay
12%10%47%423347%39%
1430
16th to endDay
14%8%36%8%35%45%8%30%
1440
December1st to 15thDay
13%12%5%9%8%45%5%45%25%
1440
16th to endDay
17%16%8%9%5%23346%22%
1479
January1st to 15thNight
8%8%5%9%7%46%46%7%31%
2588
16th to endNight
10%12%48%6%3445%7%29%
2505
February1st to 15thNight
8%11%46%6%35%45%6%37%
2285
16th to endNight
8%8%36%7%45%46%7%37%
2049
March1st to 15thNight
12%8%46%5%34347%39%
1968
16th to endNight
16%8%47%5%33346%35%
2112
April1st to 15thNight
15%8%35%42345%5%40%
1814
16th to endNight
23%10%25%423445%34%
1620
May1st to 15thNight
18%6%24424446%40%
1536
16th to endNight
13%42442446%9%44%
1496
June1st to 15thNight
11%31432445%9%47%
1371
16th to endNight
7%21332346%7%56%
1260
July1st to 15thNight
321432346%9%58%
1281
16th to endNight
5%22232345%8%59%
1578
August1st to 15thNight
6%325%42445%7%54%
1620
16th to endNight
8%323323347%57%
1756
September1st to 15thNight
8%313313448%56%
1806
16th to endNight
11%424323347%52%
1917
October1st to 15thNight
14%5%24322346%49%
1980
16th to endNight
19%9%35%323336%39%
2112
November1st to 15thNight
12%6%35%5%2345%6%43%
2426
16th to endNight
12%9%5%6%5%2345%6%38%
2520
December1st to 15thNight
11%10%5%8%7%45%445%31%
2520
16th to endNight
17%13%5%8%7%34445%23%
2739

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
9%11%6%9%6%46%5%5%8%26%
1343
16th to endDay
7%14%5%9%6%47%5%5%7%25%
1716
February1st to 15thDay
7%11%5%8%7%36%5%5%8%30%
1575
16th to endDay
9%9%5%9%9%46%46%6%28%
1434
March1st to 15thDay
13%11%5%7%6%34347%32%
1980
16th to endDay
16%8%47%6%25%447%30%
2112
April1st to 15thDay
17%8%35%5%235%5%5%38%
2133
16th to endDay
24%11%36%423345%29%
2337
May1st to 15thDay
20%7%36%5%445%46%32%
2415
16th to endDay
14%6%35%6%25%6%5%8%35%
2617
June1st to 15thDay
14%7%245%346%5%8%36%
2586
16th to endDay
9%414425%5%6%9%45%
2700
July1st to 15thDay
6%312425%5%6%8%52%
2676
16th to endDay
5%3144245%7%10%50%
2587
August1st to 15thDay
9%5%25%5%35%5%6%8%40%
2340
16th to endDay
12%5%23423448%47%
2445
September1st to 15thDay
10%32442445%8%48%
2153
16th to endDay
15%5%25%313446%45%
1868
October1st to 15thDay
16%7%15%423337%43%
1650
16th to endDay
18%9%36%423346%36%
1760
November1st to 15thDay
12%10%36%5%23446%39%
1430
16th to endDay
14%9%36%7%35%46%8%30%
1440
December1st to 15thDay
13%12%5%8%8%45%5%45%25%
1440
16th to endDay
17%16%8%9%5%23345%22%
1479
January1st to 15thNight
8%8%5%8%7%46%46%7%32%
2588
16th to endNight
10%12%5%8%6%3446%7%29%
2505
February1st to 15thNight
8%12%46%5%35%446%37%
2278
16th to endNight
8%8%36%7%45%46%6%37%
2049
March1st to 15thNight
11%8%46%5%34347%39%
1980
16th to endNight
15%8%47%5%33346%35%
2112
April1st to 15thNight
14%8%36%42345%5%40%
1814
16th to endNight
23%9%25%423445%34%
1620
May1st to 15thNight
18%6%2443445%6%40%
1535
16th to endNight
13%42443346%8%44%
1496
June1st to 15thNight
11%32432445%9%47%
1371
16th to endNight
7%21332345%7%56%
1260
July1st to 15thNight
322442346%9%57%
1281
16th to endNight
5%22232345%8%59%
1578
August1st to 15thNight
6%225%43435%7%54%
1620
16th to endNight
8%313323346%57%
1756
September1st to 15thNight
8%21331345%8%56%
1806
16th to endNight
11%424423347%52%
1917
October1st to 15thNight
14%5%24313346%50%
1980
16th to endNight
19%9%25%323346%39%
2112
November1st to 15thNight
11%6%36%5%2345%6%43%
2426
16th to endNight
12%9%46%5%2345%6%37%
2520
December1st to 15thNight
12%10%5%7%8%45%446%31%
2520
16th to endNight
17%13%5%8%7%3445%5%23%
2739

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
9%11%6%10%6%45%5%5%7%26%
1343
16th to endDay
8%13%6%8%7%47%6%5%7%24%
1716
February1st to 15thDay
7%11%49%7%35%5%6%7%30%
1575
16th to endDay
9%10%5%8%9%35%5%5%6%28%
1434
March1st to 15thDay
13%11%5%7%6%2435%7%32%
1980
16th to endDay
17%8%47%6%2445%6%31%
2110
April1st to 15thDay
17%8%36%5%1345%6%37%
2133
16th to endDay
23%12%36%423335%29%
2337
May1st to 15thDay
20%7%36%5%34445%33%
2415
16th to endDay
14%6%35%6%345%6%8%36%
2617
June1st to 15thDay
14%7%35%5%25%5%6%7%36%
2586
16th to endDay
9%4245%35%5%6%9%45%
2700
July1st to 15thDay
6%3134245%6%8%52%
2676
16th to endDay
5%3144245%6%10%49%
2587
August1st to 15thDay
9%5%25%5%5%5%5%6%8%41%
2340
16th to endDay
12%424423448%48%
2445
September1st to 15thDay
9%32442445%8%48%
2153
16th to endDay
15%5%25%423447%44%
1868
October1st to 15thDay
17%6%24423346%43%
1650
16th to endDay
18%9%36%423346%36%
1760
November1st to 15thDay
12%9%46%5%2345%6%39%
1430
16th to endDay
14%9%36%7%45%46%8%31%
1440
December1st to 15thDay
13%12%6%9%7%46%45%426%
1440
16th to endDay
18%15%7%9%6%33245%22%
1479
January1st to 15thNight
8%8%5%8%6%46%46%7%32%
2588
16th to endNight
11%12%48%6%345%6%7%29%
2505
February1st to 15thNight
7%12%5%5%5%345%46%37%
2278
16th to endNight
8%8%46%7%35%5%6%7%36%
2049
March1st to 15thNight
12%8%46%5%25%346%40%
1980
16th to endNight
15%9%46%5%24446%36%
2112
April1st to 15thNight
14%9%35%43345%5%40%
1814
16th to endNight
23%9%245%14435%34%
1620
May1st to 15thNight
17%6%25%5%2445%5%40%
1535
16th to endNight
12%5%2442445%9%44%
1496
June1st to 15thNight
11%31342335%9%47%
1371
16th to endNight
7%21322445%7%57%
1260
July1st to 15thNight
321432346%8%58%
1281
16th to endNight
431242346%7%60%
1578
August1st to 15thNight
7%31443435%7%54%
1620
16th to endNight
8%313423446%57%
1756
September1st to 15thNight
8%21331345%8%56%
1806
16th to endNight
11%42432335%6%52%
1917
October1st to 15thNight
14%5%24323336%49%
1980
16th to endNight
19%9%25%313336%40%
2112
November1st to 15thNight
12%6%36%424446%44%
2426
16th to endNight
13%9%5%6%5%3345%6%38%
2520
December1st to 15thNight
12%10%5%7%7%45%446%31%
2520
16th to endNight
17%13%5%7%8%34446%23%
2739

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
55%5%12%17%7%
1344
16th to endDay
56%6%14%17%3
1716
February1st to 15thDay
51%6%15%19%5%1
1576
16th to endDay
54%6%12%20%6%
1434
March1st to 15thDay
51%5%14%20%6%
1980
16th to endDay
52%6%13%23%3
2112
April1st to 15thDay
46%5%11%23%11%1
2133
16th to endDay
56%5%11%17%8%1
2337
May1st to 15thDay
52%6%11%21%7%
2415
16th to endDay
44%7%13%23%10%
2621
June1st to 15thDay
43%8%15%24%8%
2586
16th to endDay
33%8%17%29%10%1
2700
July1st to 15thDay
26%7%17%29%16%2
2519
16th to endDay
27%9%17%27%16%1
2425
August1st to 15thDay
37%9%14%26%9%2
2326
16th to endDay
33%5%16%29%13%1
2445
September1st to 15thDay
32%5%16%33%11%
2153
16th to endDay
39%5%13%32%9%
1868
October1st to 15thDay
41%413%26%12%1
1650
16th to endDay
48%415%22%9%
1760
November1st to 15thDay
44%5%11%22%14%1
1430
16th to endDay
49%6%17%16%8%1
1440
December1st to 15thDay
59%6%13%14%5%
1440
16th to endDay
64%49%15%5%
1479
January1st to 15thNight
49%6%12%22%8%
2588
16th to endNight
52%5%15%20%6%
2505
February1st to 15thNight
47%416%20%10%
2288
16th to endNight
44%7%13%22%11%
2049
March1st to 15thNight
45%5%15%23%9%
1980
16th to endNight
49%5%13%25%4
2112
April1st to 15thNight
44%410%26%12%1
1814
16th to endNight
52%48%18%14%2
1620
May1st to 15thNight
44%6%11%22%11%1
1536
16th to endNight
35%6%14%25%14%2
1498
June1st to 15thNight
32%5%16%31%12%1
1371
16th to endNight
25%5%14%30%18%3
1260
July1st to 15thNight
23%418%34%16%2
1210
16th to endNight
22%5%16%33%16%4
1477
August1st to 15thNight
28%6%13%31%15%3
1610
16th to endNight
27%5%16%30%18%2
1756
September1st to 15thNight
26%5%14%34%18%
1806
16th to endNight
32%413%34%14%1
1917
October1st to 15thNight
36%311%29%16%2
1980
16th to endNight
46%413%23%11%
2112
November1st to 15thNight
41%413%23%15%1
2426
16th to endNight
46%5%17%18%9%1
2520
December1st to 15thNight
54%6%13%19%6%
2520
16th to endNight
61%6%11%14%5%
2739

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
17%8%34%23%13%2
90
16th to endDay
21%9%34%30%4
96
February1st to 15thDay
15%15%41%23%4
90
16th to endDay
18%12%35%23%9%
81
March1st to 15thDay
25%6%38%27%1
90
16th to endDay
23%13%22%31%7%1
96
April1st to 15thDay
19%13%28%26%10%1
252
16th to endDay
30%8%28%21%8%1
447
May1st to 15thDay
22%11%32%23%8%2
468
16th to endDay
18%6%34%25%12%3
517
June1st to 15thDay
15%7%29%28%16%2
495
16th to endDay
10%6%33%30%14%4
495
July1st to 15thDay
6%5%26%31%22%6%
475
16th to endDay
7%5%22%34%26%3
515
August1st to 15thDay
10%320%34%26%3
493
16th to endDay
14%322%31%21%5%
485
September1st to 15thDay
9%5%25%35%17%5%
308
16th to endDay
24%5%29%24%9%6%
111
October1st to 15thDay
5%13%35%23%14%7%
90
16th to endDay
23%8%34%14%17%1
96
November1st to 15thDay
5%8%26%42%14%2
90
16th to endDay
36%6%33%16%6%
90
December1st to 15thDay
20%12%27%34%5%
90
16th to endDay
36%11%33%16%2
96
January1st to 15thNight
12%11%35%29%9%2
900
16th to endNight
16%10%36%31%5%
960
February1st to 15thNight
13%10%32%33%8%1
880
16th to endNight
12%9%37%29%10%1
787
March1st to 15thNight
16%7%36%28%10%
540
16th to endNight
18%8%29%30%10%2
576
April1st to 15thNight
18%7%35%27%9%
539
16th to endNight
27%7%28%26%8%1
540
May1st to 15thNight
21%7%35%25%8%
540
16th to endNight
16%6%30%31%12%1
563
June1st to 15thNight
13%430%39%11%
540
16th to endNight
7%230%45%13%
540
July1st to 15thNight
4128%40%22%1
510
16th to endNight
6%122%46%21%1
564
August1st to 15thNight
7%215%44%26%2
539
16th to endNight
8%223%37%24%3
573
September1st to 15thNight
8%424%37%21%3
540
16th to endNight
12%8%31%28%17%1
530
October1st to 15thNight
18%6%34%26%12%1
660
16th to endNight
25%7%27%30%8%
704
November1st to 15thNight
15%10%33%30%10%
872
16th to endNight
17%13%31%28%8%
900
December1st to 15thNight
17%9%36%29%6%
900
16th to endNight
24%9%29%28%7%1
960
Page generated at 2017-09-24 08:15:55. Version ac04

Copyright 2017 A. Danko


Litchfield High School Clear Sky Chart | Charts Home