Gilbert-Baker Campground
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Gilbert-Baker Campground clear sky chart from 2005-11-05 to 2018-01-20.

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%
16638
22%
48478
12%
16596
48%
16596
33%
28564

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%
975
21%
2716
9%
970
41%
970
29%
1676
January16th to endNight
26%
955
25%
2728
9%
955
42%
955
30%
1618
February1st to 15thNight
28%
699
15%
2253
7%
699
37%
699
24%
1399
February16th to endNight
28%
632
19%
1894
8%
632
39%
632
26%
1173
March1st to 15thNight
32%
720
21%
2160
9%
720
43%
720
32%
1279
March16th to endNight
34%
642
20%
2001
12%
642
44%
642
28%
1208
April1st to 15thNight
32%
539
19%
1798
12%
539
43%
539
25%
1103
April16th to endNight
31%
540
14%
1747
10%
540
40%
540
21%
1144
May1st to 15thNight
43%
540
19%
1533
13%
540
48%
540
29%
961
May16th to endNight
40%
562
15%
1498
9%
561
43%
561
28%
994
June1st to 15thNight
41%
540
14%
1440
7%
540
45%
540
33%
906
June16th to endNight
47%
540
20%
1440
9%
540
52%
540
47%
782
July1st to 15thNight
58%
510
17%
1360
10%
510
62%
510
41%
804
July16th to endNight
61%
564
27%
1416
17%
531
65%
531
50%
759
August1st to 15thNight
60%
539
23%
1543
17%
536
66%
536
44%
825
August16th to endNight
63%
573
28%
1910
27%
573
71%
573
43%
960
September1st to 15thNight
53%
540
25%
1800
22%
540
62%
540
36%
968
September16th to endNight
54%
537
33%
1960
28%
537
65%
537
41%
926
October1st to 15thNight
40%
672
24%
2112
15%
672
48%
672
30%
1240
October16th to endNight
42%
879
31%
2415
14%
879
52%
879
40%
1386
November1st to 15thNight
38%
950
27%
2470
11%
950
47%
950
41%
1448
November16th to endNight
35%
975
29%
2642
11%
975
50%
975
39%
1518
December1st to 15thNight
25%
975
19%
2730
6%
975
36%
975
30%
1697
December16th to endNight
27%
1040
22%
2912
8%
1040
40%
1040
31%
1790

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
7%5%2442445%8%51%
49055
Night
6%5%2442445%7%51%
48645
Cloud CoverDay
7%5%2442445%8%51%
49065
Night
6%5%2442445%7%51%
48650
Cloud CoverDay
6%5%2432445%8%51%
49063
Night
6%5%2442445%7%51%
48650
TransparencyDay
30%6%15%26%16%5%
48739
Night
31%6%15%26%16%4
48478
SeeingDay
10%9%31%29%15%2
6384
Night
9%10%37%32%9%
16644

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
46%344346%6%8%46%
1552
16th to endDay
37%24425%46%8%49%
1611
February1st to 15thDay
5%8%5%5%435%46%6%43%
1609
16th to endDay
48%46%5%2446%8%45%
1580
March1st to 15thDay
48%143235%48%51%
1790
16th to endDay
7%8%25%42445%7%47%
2221
April1st to 15thDay
9%6%35%425%45%8%43%
2150
16th to endDay
14%9%35%424346%40%
2211
May1st to 15thDay
12%6%2442445%7%44%
2415
16th to endDay
12%7%25%5%346%6%9%36%
2616
June1st to 15thDay
9%313325%47%9%48%
2520
16th to endDay
22221336%8%63%
2520
July1st to 15thDay
5%2133245%7%8%54%
2520
16th to endDay
421243447%8%56%
2656
August1st to 15thDay
32144345%7%9%53%
2406
16th to endDay
6%21231345%7%60%
2292
September1st to 15thDay
8%314313346%59%
2160
16th to endDay
7%312212237%65%
1999
October1st to 15thDay
12%5%13324345%51%
1845
16th to endDay
5%413323447%59%
1796
November1st to 15thDay
45%2431447%9%52%
1718
16th to endDay
45%23323447%56%
1644
December1st to 15thDay
36%35%6%2445%9%48%
1560
16th to endDay
6%8%45%424348%47%
1664
January1st to 15thNight
36%26%5%25%46%8%47%
2716
16th to endNight
26%35%425%5%6%7%50%
2728
February1st to 15thNight
48%36%5%25%6%5%8%42%
2250
16th to endNight
48%36%5%345%5%6%46%
1894
March1st to 15thNight
5%6%35%43445%7%49%
2147
16th to endNight
8%6%24425%5%5%8%45%
2001
April1st to 15thNight
10%6%24435%45%8%45%
1798
16th to endNight
16%7%25%5%2435%6%39%
1747
May1st to 15thNight
11%6%324245%5%8%46%
1533
16th to endNight
13%4235%2445%9%42%
1497
June1st to 15thNight
9%4133336%6%9%47%
1440
16th to endNight
3212325%46%9%58%
1440
July1st to 15thNight
7%21442335%9%53%
1440
16th to endNight
3133245%5%8%61%
1512
August1st to 15thNight
221443445%10%55%
1551
16th to endNight
341332345%7%59%
1910
September1st to 15thNight
8%5%24323436%56%
1800
16th to endNight
8%21222334463%
1960
October1st to 15thNight
11%5%33323346%50%
2112
16th to endNight
6%41442325%7%56%
2415
November1st to 15thNight
6%424433447%54%
2470
16th to endNight
442442345%8%54%
2642
December1st to 15thNight
46%35%5%3345%8%48%
2730
16th to endNight
47%35%42435%7%50%
2912

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
46%344346%6%8%46%
1552
16th to endDay
37%24425%46%8%49%
1611
February1st to 15thDay
5%8%5%5%435%5%6%6%43%
1609
16th to endDay
48%46%5%2445%7%45%
1580
March1st to 15thDay
48%25%3235%5%8%50%
1800
16th to endDay
7%8%25%42445%7%47%
2221
April1st to 15thDay
9%6%35%425%45%8%43%
2150
16th to endDay
14%9%34424346%40%
2211
May1st to 15thDay
12%6%2442445%7%44%
2415
16th to endDay
12%7%25%4346%6%9%36%
2616
June1st to 15thDay
9%313325%46%9%48%
2520
16th to endDay
22221336%8%63%
2520
July1st to 15thDay
5%2133245%7%8%54%
2520
16th to endDay
421243447%8%56%
2656
August1st to 15thDay
32134345%6%9%53%
2406
16th to endDay
6%31231345%7%60%
2292
September1st to 15thDay
8%313313346%59%
2160
16th to endDay
7%312212237%65%
1999
October1st to 15thDay
12%5%13324346%51%
1845
16th to endDay
5%413323447%59%
1796
November1st to 15thDay
45%2431446%9%52%
1718
16th to endDay
45%24323447%56%
1644
December1st to 15thDay
36%35%5%2445%9%47%
1560
16th to endDay
6%8%45%424348%47%
1664
January1st to 15thNight
36%26%5%2446%8%47%
2716
16th to endNight
26%35%425%46%7%50%
2728
February1st to 15thNight
48%36%5%25%6%5%8%42%
2243
16th to endNight
48%36%5%345%5%6%46%
1894
March1st to 15thNight
5%6%35%434447%49%
2160
16th to endNight
8%6%24425%5%5%8%45%
2001
April1st to 15thNight
10%6%34425%45%7%45%
1798
16th to endNight
16%7%25%5%2435%6%39%
1747
May1st to 15thNight
11%6%224245%5%8%46%
1532
16th to endNight
13%4235%3445%9%42%
1497
June1st to 15thNight
9%3133346%6%9%47%
1440
16th to endNight
3211325%46%9%58%
1440
July1st to 15thNight
7%32442335%9%53%
1440
16th to endNight
2133245%5%8%61%
1512
August1st to 15thNight
221443345%10%55%
1551
16th to endNight
341332345%7%59%
1910
September1st to 15thNight
8%5%24413436%56%
1800
16th to endNight
8%21222335%463%
1960
October1st to 15thNight
11%6%33323346%50%
2112
16th to endNight
6%5%1442325%7%56%
2415
November1st to 15thNight
6%42443345%7%54%
2470
16th to endNight
442442345%8%54%
2642
December1st to 15thNight
46%35%5%3345%8%48%
2730
16th to endNight
47%35%42435%7%50%
2912

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
46%434245%7%9%46%
1552
16th to endDay
37%244345%5%8%49%
1611
February1st to 15thDay
5%9%46%435%5%6%7%42%
1609
16th to endDay
47%36%5%2445%8%45%
1580
March1st to 15thDay
48%243245%5%8%51%
1800
16th to endDay
8%7%2442445%7%47%
2219
April1st to 15thDay
9%6%35%425%5%5%9%42%
2150
16th to endDay
14%8%35%424346%40%
2211
May1st to 15thDay
12%6%2443445%7%44%
2415
16th to endDay
12%7%25%435%47%10%36%
2616
June1st to 15thDay
9%413325%5%6%9%49%
2520
16th to endDay
32221346%9%63%
2520
July1st to 15thDay
42134245%7%8%54%
2520
16th to endDay
421242446%10%56%
2656
August1st to 15thDay
32144345%6%9%54%
2406
16th to endDay
6%31231335%8%60%
2292
September1st to 15thDay
8%313313345%60%
2160
16th to endDay
7%312113236%66%
1999
October1st to 15thDay
12%5%2332435%5%51%
1845
16th to endDay
5%413313347%59%
1796
November1st to 15thDay
45%25%31447%8%52%
1718
16th to endDay
45%24324447%56%
1644
December1st to 15thDay
36%35%6%345%5%9%48%
1560
16th to endDay
6%7%46%324347%48%
1664
January1st to 15thNight
46%26%5%2446%7%47%
2716
16th to endNight
36%35%435%45%7%50%
2728
February1st to 15thNight
48%36%5%25%6%5%8%42%
2243
16th to endNight
48%26%5%345%5%6%46%
1894
March1st to 15thNight
5%5%35%434447%50%
2160
16th to endNight
8%5%24425%5%5%8%46%
2001
April1st to 15thNight
10%6%245%25%447%45%
1798
16th to endNight
16%6%25%5%24447%39%
1747
May1st to 15thNight
11%6%234235%5%7%47%
1532
16th to endNight
13%415%435%5%5%8%43%
1497
June1st to 15thNight
9%32233447%10%47%
1440
16th to endNight
32122245%6%8%59%
1440
July1st to 15thNight
7%22342435%9%53%
1440
16th to endNight
21124245%49%61%
1512
August1st to 15thNight
22144245%5%10%55%
1551
16th to endNight
332331345%6%59%
1910
September1st to 15thNight
8%424323346%56%
1800
16th to endNight
8%312223345%63%
1960
October1st to 15thNight
11%5%24324447%50%
2112
16th to endNight
6%414423347%57%
2415
November1st to 15thNight
6%42443435%7%54%
2470
16th to endNight
35%2442445%8%54%
2642
December1st to 15thNight
46%35%5%2445%7%48%
2730
16th to endNight
47%3442435%7%50%
2912

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
32%6%20%29%9%1
1553
16th to endDay
30%6%18%29%13%1
1611
February1st to 15thDay
39%7%17%22%9%2
1610
16th to endDay
35%6%18%24%10%4
1580
March1st to 15thDay
30%5%18%27%15%2
1800
16th to endDay
37%6%14%28%12%1
2221
April1st to 15thDay
37%7%16%26%10%2
2150
16th to endDay
43%5%15%21%12%1
2211
May1st to 15thDay
38%5%16%26%11%
2415
16th to endDay
41%8%18%20%9%1
2620
June1st to 15thDay
30%7%17%25%16%3
2520
16th to endDay
17%5%13%30%24%9%
2520
July1st to 15thDay
25%7%12%22%21%10%
2371
16th to endDay
22%5%12%24%22%12%
2489
August1st to 15thDay
24%7%15%25%17%9%
2390
16th to endDay
21%410%24%26%12%
2292
September1st to 15thDay
26%47%22%26%12%
2160
16th to endDay
20%210%33%28%4
1999
October1st to 15thDay
33%5%11%25%19%4
1845
16th to endDay
24%414%32%17%6%
1796
November1st to 15thDay
26%5%16%26%18%6%
1718
16th to endDay
26%5%16%31%18%2
1644
December1st to 15thDay
32%7%20%25%13%1
1560
16th to endDay
35%6%17%26%12%1
1664
January1st to 15thNight
32%7%17%26%13%2
2716
16th to endNight
29%7%16%28%15%2
2728
February1st to 15thNight
37%7%19%24%9%2
2253
16th to endNight
36%6%15%24%12%4
1894
March1st to 15thNight
32%5%15%26%15%3
2160
16th to endNight
35%5%17%26%13%1
2001
April1st to 15thNight
36%7%14%25%13%3
1798
16th to endNight
44%5%13%22%12%1
1747
May1st to 15thNight
34%7%16%26%13%1
1533
16th to endNight
37%9%18%21%11%1
1498
June1st to 15thNight
31%8%21%23%11%3
1440
16th to endNight
19%8%15%30%19%6%
1440
July1st to 15thNight
28%6%12%26%17%9%
1360
16th to endNight
19%6%12%28%21%11%
1416
August1st to 15thNight
22%6%16%29%17%6%
1543
16th to endNight
24%49%22%27%11%
1910
September1st to 15thNight
29%48%24%23%9%
1800
16th to endNight
22%39%32%24%7%
1960
October1st to 15thNight
34%5%13%21%20%4
2112
16th to endNight
27%411%27%20%7%
2415
November1st to 15thNight
28%415%24%21%5%
2470
16th to endNight
26%5%14%30%18%4
2642
December1st to 15thNight
33%7%17%27%12%2
2730
16th to endNight
32%6%18%27%12%2
2912

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
8%14%31%30%12%2
135
16th to endDay
6%14%37%22%14%3
109
February1st to 15thDay
13%21%46%17%1
90
16th to endDay
14%24%30%22%7%
81
March1st to 15thDay
6%11%50%26%5%
90
16th to endDay
15%16%36%24%7%
271
April1st to 15thDay
10%23%39%20%5%
269
16th to endDay
25%14%31%18%8%1
321
May1st to 15thDay
16%11%32%22%14%3
468
16th to endDay
17%11%28%25%15%1
517
June1st to 15thDay
8%7%30%29%18%5%
495
16th to endDay
5%6%35%34%16%2
495
July1st to 15thDay
7%425%36%23%4
475
16th to endDay
6%224%41%23%1
515
August1st to 15thDay
4324%44%21%1
424
16th to endDay
7%425%33%24%5%
332
September1st to 15thDay
10%5%26%33%19%4
315
16th to endDay
12%9%23%33%15%5%
154
October1st to 15thDay
8%11%34%28%14%2
135
16th to endDay
6%15%29%27%16%3
144
November1st to 15thDay
25%39%31%14%5%
135
16th to endDay
18%14%37%24%5%
135
December1st to 15thDay
8%18%50%16%6%
135
16th to endDay
11%13%51%20%2
144
January1st to 15thNight
7%18%39%25%8%1
975
16th to endNight
6%19%43%24%5%
955
February1st to 15thNight
7%14%43%28%6%
704
16th to endNight
10%14%41%27%5%
632
March1st to 15thNight
8%9%44%30%5%
720
16th to endNight
11%11%39%31%5%
642
April1st to 15thNight
11%12%39%31%4
539
16th to endNight
19%11%29%30%9%
540
May1st to 15thNight
14%8%30%33%12%
540
16th to endNight
16%6%33%33%9%
563
June1st to 15thNight
10%6%37%33%10%1
540
16th to endNight
5%242%41%8%
540
July1st to 15thNight
7%224%45%17%1
510
16th to endNight
3227%47%18%
564
August1st to 15thNight
6%27%48%15%1
539
16th to endNight
5%224%51%16%
573
September1st to 15thNight
10%427%36%19%1
540
16th to endNight
9%6%28%39%15%1
537
October1st to 15thNight
16%8%30%31%11%1
672
16th to endNight
8%8%36%34%11%
879
November1st to 15thNight
8%10%39%31%9%1
950
16th to endNight
5%13%42%31%5%
975
December1st to 15thNight
8%15%46%23%5%
975
16th to endNight
9%13%45%26%5%
1040
Page generated at 2018-01-21 10:19:24. Version ac04

Copyright 2018 A. Danko


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