Lee & Rose Warner Nature Center
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lee & Rose Warner Nature Center clear sky chart from 2005-11-05 to 2017-10-31.

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
33%
16304
16%
47399
8%
16258
40%
16258
22%
31689

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
26%
900
13%
2506
6%
895
32%
895
18%
1813
January16th to endNight
20%
960
11%
2566
3%
960
26%
960
14%
1948
February1st to 15thNight
25%
880
15%
2288
4%
876
31%
876
19%
1620
February16th to endNight
28%
742
14%
2004
4%
742
35%
742
19%
1417
March1st to 15thNight
27%
597
15%
2037
9%
597
35%
597
18%
1340
March16th to endNight
29%
576
16%
2085
13%
576
37%
576
16%
1409
April1st to 15thNight
27%
539
17%
1797
10%
539
38%
539
18%
1192
April16th to endNight
22%
540
16%
1685
7%
540
33%
540
14%
1217
May1st to 15thNight
26%
540
15%
1476
6%
540
32%
540
20%
1041
May16th to endNight
38%
562
16%
1498
5%
561
45%
561
26%
993
June1st to 15thNight
39%
540
12%
1440
4%
540
43%
540
28%
917
June16th to endNight
45%
540
15%
1440
6%
540
50%
540
35%
852
July1st to 15thNight
54%
510
15%
1360
7%
510
56%
510
40%
778
July16th to endNight
54%
564
20%
1417
9%
531
62%
531
44%
782
August1st to 15thNight
62%
539
21%
1603
18%
536
66%
536
35%
907
August16th to endNight
53%
573
22%
1803
19%
573
61%
573
33%
1027
September1st to 15thNight
54%
540
24%
1800
21%
540
64%
540
34%
950
September16th to endNight
42%
594
20%
1974
14%
594
51%
594
30%
1138
October1st to 15thNight
37%
720
23%
2160
14%
720
44%
720
29%
1286
October16th to endNight
32%
768
17%
2336
10%
768
39%
768
20%
1573
November1st to 15thNight
28%
820
20%
2396
10%
820
37%
820
23%
1573
November16th to endNight
26%
900
15%
2520
7%
900
33%
900
16%
1839
December1st to 15thNight
19%
900
10%
2520
3%
900
25%
900
13%
1936
December16th to endNight
18%
960
11%
2688
3%
960
25%
960
11%
2141

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%8%36%5%3445%7%36%
48362
Night
12%8%36%5%34446%39%
47567
Cloud CoverDay
25%7%25%423346%31%
48373
Night
24%7%25%423345%35%
47571
Cloud CoverDay
13%8%36%5%3445%7%36%
48371
Night
12%8%36%5%3445%6%39%
47571
TransparencyDay
46%414%23%9%
48048
Night
44%413%24%11%1
47399
SeeingDay
16%14%25%25%13%3
6276
Night
15%20%25%27%10%1
16305

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%6%8%9%45%5%46%28%
1432
16th to endDay
9%13%6%12%7%46%45%7%22%
1656
February1st to 15thDay
8%12%6%9%7%3445%5%31%
1575
16th to endDay
10%12%5%8%6%35%35%6%31%
1467
March1st to 15thDay
14%10%47%6%34347%34%
1921
16th to endDay
17%10%46%4345%46%30%
2139
April1st to 15thDay
17%9%36%424346%37%
2151
16th to endDay
22%11%36%5%25%436%28%
2274
May1st to 15thDay
20%8%36%5%24446%31%
2475
16th to endDay
12%7%35%5%45%46%7%38%
2617
June1st to 15thDay
17%5%2442446%8%38%
2520
16th to endDay
9%5%25%5%36%6%6%9%38%
2520
July1st to 15thDay
7%3134245%7%9%48%
2520
16th to endDay
8%315%435%5%6%9%46%
2655
August1st to 15thDay
9%425%445%6%6%8%41%
2346
16th to endDay
12%42432336%7%47%
2399
September1st to 15thDay
10%4245%25%5%6%8%45%
2160
16th to endDay
15%5%245%25%45%7%40%
1971
October1st to 15thDay
16%7%34423346%43%
1800
16th to endDay
18%9%36%5%2334437%
1887
November1st to 15thDay
11%11%48%5%2445%437%
1461
16th to endDay
17%9%35%7%345%6%7%29%
1440
December1st to 15thDay
15%11%7%8%9%35%445%23%
1440
16th to endDay
18%16%7%13%6%3422320%
1536
January1st to 15thNight
10%9%6%7%6%35%45%6%32%
2506
16th to endNight
11%13%5%9%7%345%45%28%
2566
February1st to 15thNight
6%10%6%9%6%35%446%37%
2285
16th to endNight
9%9%36%6%45%446%36%
2004
March1st to 15thNight
12%9%47%5%3435%6%38%
2025
16th to endNight
16%9%47%424337%36%
2085
April1st to 15thNight
19%8%25%42335%6%37%
1797
16th to endNight
23%8%35%434445%30%
1685
May1st to 15thNight
19%7%34324346%38%
1476
16th to endNight
9%436%5%35%5%6%9%40%
1496
June1st to 15thNight
12%5%24425%5%5%8%44%
1440
16th to endNight
6%3125%35%45%7%52%
1440
July1st to 15thNight
4312435%45%9%54%
1440
16th to endNight
42133245%7%9%54%
1513
August1st to 15thNight
7%3144245%6%7%51%
1612
16th to endNight
9%424423346%53%
1803
September1st to 15thNight
7%42333335%7%55%
1800
16th to endNight
12%3245%23446%49%
1974
October1st to 15thNight
16%5%23223346%49%
2160
16th to endNight
18%10%35%423345%39%
2336
November1st to 15thNight
13%8%46%423445%42%
2396
16th to endNight
14%9%47%6%3445%6%31%
2520
December1st to 15thNight
13%13%5%10%7%25%335%28%
2520
16th to endNight
17%15%7%10%7%34345%22%
2688

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
23%8%46%8%35%5%45%25%
1432
16th to endDay
24%12%410%6%34345%19%
1656
February1st to 15thDay
23%10%5%7%5%3433427%
1575
16th to endDay
23%11%48%5%24335%27%
1467
March1st to 15thDay
27%8%36%423236%29%
1932
16th to endDay
30%9%26%423436%25%
2139
April1st to 15thDay
30%8%25%42333431%
2151
16th to endDay
36%10%25%432335%22%
2274
May1st to 15thDay
33%7%26%5%23345%26%
2475
16th to endDay
28%7%14433345%31%
2617
June1st to 15thDay
31%5%2332345%6%30%
2520
16th to endDay
25%4145%245%5%6%32%
2520
July1st to 15thDay
23%31332335%8%40%
2520
16th to endDay
24%21442445%8%37%
2655
August1st to 15thDay
17%4145%35%5%6%7%37%
2346
16th to endDay
19%42432335%6%45%
2399
September1st to 15thDay
17%4134345%5%8%42%
2160
16th to endDay
21%41442445%5%39%
1971
October1st to 15thDay
23%6%25%323335%41%
1800
16th to endDay
24%8%35%423235%35%
1887
November1st to 15thDay
23%9%37%42334334%
1461
16th to endDay
30%7%25%6%2335%5%26%
1440
December1st to 15thDay
29%10%5%8%6%3343320%
1440
16th to endDay
29%14%6%10%7%2222317%
1536
January1st to 15thNight
24%8%46%5%2435%5%29%
2506
16th to endNight
26%11%38%6%23445%23%
2566
February1st to 15thNight
21%10%48%423335%32%
2278
16th to endNight
22%7%36%5%45%345%31%
2004
March1st to 15thNight
24%8%36%423245%34%
2037
16th to endNight
30%8%25%423225%31%
2085
April1st to 15thNight
31%7%24322345%32%
1797
16th to endNight
36%8%24433335%23%
1685
May1st to 15thNight
33%6%23312335%32%
1475
16th to endNight
25%425%424446%34%
1496
June1st to 15thNight
26%414324446%37%
1440
16th to endNight
22%313423345%45%
1440
July1st to 15thNight
21%21232335%7%44%
1440
16th to endNight
20%21222336%7%46%
1513
August1st to 15thNight
15%31342345%6%47%
1612
16th to endNight
16%413323246%50%
1803
September1st to 15thNight
15%314323346%52%
1800
16th to endNight
18%313422346%47%
1974
October1st to 15thNight
23%42322234446%
2160
16th to endNight
25%8%24322345%36%
2336
November1st to 15thNight
25%7%25%32234438%
2396
16th to endNight
27%7%46%5%33345%27%
2520
December1st to 15thNight
28%12%38%6%2333423%
2520
16th to endNight
29%12%5%9%6%2233419%
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
9%10%7%7%9%35%5%45%28%
1432
16th to endDay
9%13%6%11%7%36%45%6%23%
1656
February1st to 15thDay
8%11%7%9%6%44445%31%
1575
16th to endDay
10%12%5%9%6%35%446%31%
1467
March1st to 15thDay
14%10%5%7%5%33347%33%
1932
16th to endDay
17%11%37%5%33447%30%
2137
April1st to 15thDay
16%9%36%43335%6%37%
2151
16th to endDay
22%12%35%5%34346%28%
2274
May1st to 15thDay
20%7%36%6%34346%31%
2475
16th to endDay
13%7%25%5%35%5%5%7%37%
2617
June1st to 15thDay
17%5%2342446%9%38%
2520
16th to endDay
9%5%25%5%35%7%6%8%39%
2520
July1st to 15thDay
7%414435%46%9%48%
2520
16th to endDay
8%225%435%5%6%10%45%
2655
August1st to 15thDay
9%425%5%46%5%6%8%41%
2346
16th to endDay
12%425%42335%7%47%
2399
September1st to 15thDay
10%4244346%5%8%45%
2160
16th to endDay
15%5%14425%46%6%40%
1971
October1st to 15thDay
16%7%25%323345%43%
1800
16th to endDay
18%10%36%423346%37%
1887
November1st to 15thDay
11%11%5%7%42435%5%37%
1461
16th to endDay
17%9%36%7%25%46%7%30%
1440
December1st to 15thDay
15%11%6%9%9%4444424%
1440
16th to endDay
17%17%7%11%8%2422320%
1536
January1st to 15thNight
11%9%6%7%6%25%46%6%32%
2506
16th to endNight
12%12%5%9%7%34446%28%
2566
February1st to 15thNight
6%11%5%9%5%25%446%37%
2278
16th to endNight
9%9%37%6%46%5%46%36%
2004
March1st to 15thNight
12%9%47%5%2435%5%39%
2037
16th to endNight
16%9%46%5%24336%35%
2085
April1st to 15thNight
19%8%35%32345%5%37%
1797
16th to endNight
23%9%35%5%34445%30%
1685
May1st to 15thNight
20%7%34424445%39%
1475
16th to endNight
9%426%5%35%5%6%9%40%
1496
June1st to 15thNight
12%5%15%3345%5%8%44%
1440
16th to endNight
6%31443446%6%54%
1440
July1st to 15thNight
42134345%6%10%53%
1440
16th to endNight
431332447%9%54%
1513
August1st to 15thNight
7%3144245%6%7%51%
1612
16th to endNight
9%414424246%53%
1803
September1st to 15thNight
8%314333346%56%
1800
16th to endNight
12%4135%2345%7%48%
1974
October1st to 15thNight
16%5%23322445%49%
2160
16th to endNight
19%10%25%322445%39%
2336
November1st to 15thNight
13%8%46%42344443%
2396
16th to endNight
14%9%47%6%3445%7%31%
2520
December1st to 15thNight
13%14%410%7%35%345%28%
2520
16th to endNight
16%15%7%10%7%33345%22%
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
56%412%19%6%
1433
16th to endDay
60%5%15%14%4
1656
February1st to 15thDay
53%314%20%6%1
1576
16th to endDay
53%5%12%22%6%
1467
March1st to 15thDay
51%317%19%7%
1932
16th to endDay
53%413%23%4
2139
April1st to 15thDay
48%312%22%11%1
2151
16th to endDay
57%412%16%9%
2274
May1st to 15thDay
52%413%21%7%
2475
16th to endDay
44%412%24%11%1
2621
June1st to 15thDay
41%416%27%9%
2520
16th to endDay
39%6%15%28%9%1
2520
July1st to 15thDay
30%5%14%31%15%1
2371
16th to endDay
32%5%18%26%15%1
2488
August1st to 15thDay
38%5%15%29%10%1
2331
16th to endDay
35%317%28%13%1
2399
September1st to 15thDay
34%6%14%34%10%
2160
16th to endDay
41%5%15%30%7%
1971
October1st to 15thDay
42%313%27%12%
1800
16th to endDay
49%314%22%8%
1887
November1st to 15thDay
47%412%21%12%1
1461
16th to endDay
52%5%19%15%6%1
1440
December1st to 15thDay
63%5%12%14%4
1440
16th to endDay
69%39%12%4
1536
January1st to 15thNight
52%413%22%7%
2506
16th to endNight
56%416%16%5%
2566
February1st to 15thNight
48%413%24%7%
2288
16th to endNight
48%413%24%8%
2004
March1st to 15thNight
46%414%22%10%
2037
16th to endNight
49%413%23%7%
2085
April1st to 15thNight
47%37%25%14%1
1797
16th to endNight
54%49%17%11%2
1685
May1st to 15thNight
47%5%13%20%11%1
1476
16th to endNight
39%5%12%25%15%1
1498
June1st to 15thNight
36%416%28%12%1
1440
16th to endNight
29%414%31%16%3
1440
July1st to 15thNight
26%415%33%17%2
1360
16th to endNight
22%5%17%32%18%4
1417
August1st to 15thNight
29%5%14%29%16%3
1603
16th to endNight
31%5%14%28%15%3
1803
September1st to 15thNight
28%314%34%17%
1800
16th to endNight
34%415%31%13%
1974
October1st to 15thNight
36%311%32%14%2
2160
16th to endNight
48%313%22%11%
2336
November1st to 15thNight
43%312%24%14%
2396
16th to endNight
52%5%15%17%8%1
2520
December1st to 15thNight
59%413%18%4
2520
16th to endNight
65%312%14%4
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
22%10%34%24%6%2
90
16th to endDay
23%7%35%28%5%
96
February1st to 15thDay
12%22%45%17%2
90
16th to endDay
18%16%32%27%41
81
March1st to 15thDay
21%6%44%22%5%
90
16th to endDay
26%10%32%21%6%1
123
April1st to 15thDay
19%20%24%26%8%
270
16th to endDay
29%21%24%16%8%
384
May1st to 15thDay
23%23%22%21%7%2
468
16th to endDay
17%19%24%22%12%4
517
June1st to 15thDay
16%17%25%23%13%3
495
16th to endDay
13%17%26%25%13%3
495
July1st to 15thDay
8%12%21%28%18%10%
475
16th to endDay
8%16%20%28%20%5%
515
August1st to 15thDay
10%8%19%33%22%5%
493
16th to endDay
16%8%19%29%20%6%
439
September1st to 15thDay
10%7%26%31%19%4
315
16th to endDay
17%9%25%29%14%2
195
October1st to 15thDay
14%11%32%22%14%3
135
16th to endDay
24%9%34%22%8%
144
November1st to 15thDay
11%334%33%15%2
90
16th to endDay
36%10%28%18%5%
90
December1st to 15thDay
25%11%40%17%5%
90
16th to endDay
33%16%36%12%1
96
January1st to 15thNight
13%24%25%27%7%1
900
16th to endNight
16%23%29%25%4
960
February1st to 15thNight
12%25%28%25%6%1
880
16th to endNight
12%23%29%25%8%
742
March1st to 15thNight
12%23%29%26%7%
597
16th to endNight
19%22%24%22%8%1
576
April1st to 15thNight
19%22%25%25%5%
539
16th to endNight
25%22%25%19%6%
540
May1st to 15thNight
23%21%25%23%5%
540
16th to endNight
11%21%22%28%14%1
563
June1st to 15thNight
11%20%24%34%9%
540
16th to endNight
9%18%22%36%12%
540
July1st to 15thNight
6%13%20%33%23%1
510
16th to endNight
6%17%17%38%19%1
564
August1st to 15thNight
8%11%12%41%23%2
539
16th to endNight
9%10%21%33%21%2
573
September1st to 15thNight
8%11%20%38%16%4
540
16th to endNight
13%13%26%29%16%1
594
October1st to 15thNight
19%12%27%26%11%1
720
16th to endNight
24%14%23%28%8%
768
November1st to 15thNight
15%22%28%24%7%1
820
16th to endNight
15%27%26%23%6%
900
December1st to 15thNight
19%24%30%20%5%
900
16th to endNight
20%23%24%24%5%
960
Page generated at 2017-11-01 16:23:30. Version ac04

Copyright 2017 A. Danko


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