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 2017-09-17.

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
39%
16065
22%
46846
12%
16023
48%
16023
33%
27594

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%
900
23%
2506
10%
895
41%
895
29%
1545
January16th to endNight
25%
930
24%
2658
8%
930
41%
930
29%
1581
February1st to 15thNight
27%
699
15%
2253
7%
699
37%
699
24%
1399
February16th to endNight
29%
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
13%
642
44%
642
28%
1208
April1st to 15thNight
31%
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
49%
540
29%
961
May16th to endNight
40%
562
15%
1498
9%
561
44%
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
60%
564
27%
1416
17%
531
65%
531
50%
759
August1st to 15thNight
59%
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
54%
540
25%
1800
22%
540
63%
540
36%
968
September16th to endNight
56%
498
32%
1817
29%
498
66%
498
43%
836
October1st to 15thNight
41%
616
24%
1936
15%
616
49%
616
30%
1145
October16th to endNight
42%
806
28%
2214
13%
806
51%
806
39%
1292
November1st to 15thNight
39%
875
27%
2275
12%
875
47%
875
42%
1310
November16th to endNight
36%
900
28%
2439
11%
900
49%
900
39%
1416
December1st to 15thNight
25%
900
18%
2520
6%
900
36%
900
30%
1568
December16th to endNight
27%
960
22%
2688
7%
960
41%
960
31%
1636

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%
47937
Night
6%5%2442445%7%50%
47013
Cloud CoverDay
7%5%2442445%8%51%
47947
Night
6%5%2442445%7%50%
47018
Cloud CoverDay
6%5%2442445%8%51%
47945
Night
6%5%2442445%7%51%
47018
TransparencyDay
30%6%15%26%16%5%
47621
Night
31%6%15%26%16%4
46846
SeeingDay
10%9%30%30%16%2
6008
Night
9%10%37%32%9%
16071

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%444345%6%9%47%
1432
16th to endDay
38%24425%46%7%49%
1577
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
6%312112237%67%
1847
October1st to 15thDay
11%5%13324346%50%
1691
16th to endDay
6%413323447%58%
1647
November1st to 15thDay
45%3431446%9%53%
1583
16th to endDay
46%343235%47%55%
1518
December1st to 15thDay
46%35%6%2445%9%47%
1440
16th to endDay
5%7%45%424338%48%
1536
January1st to 15thNight
37%27%5%25%46%7%47%
2506
16th to endNight
26%35%425%5%6%7%49%
2658
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
7%21222335%464%
1817
October1st to 15thNight
11%5%33324446%49%
1936
16th to endNight
6%5%1442325%7%55%
2214
November1st to 15thNight
5%424323447%56%
2275
16th to endNight
45%2442345%8%54%
2439
December1st to 15thNight
5%6%45%5%2345%8%48%
2520
16th to endNight
47%35%42435%7%51%
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
46%45%3346%6%8%47%
1432
16th to endDay
38%24425%46%8%48%
1577
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
6%312112237%67%
1847
October1st to 15thDay
11%5%13324346%50%
1691
16th to endDay
6%5%13323447%58%
1647
November1st to 15thDay
45%2431446%9%53%
1583
16th to endDay
46%243235%47%55%
1518
December1st to 15thDay
46%35%6%2445%9%47%
1440
16th to endDay
6%7%45%424338%48%
1536
January1st to 15thNight
36%27%5%2446%8%47%
2506
16th to endNight
26%35%425%46%7%49%
2658
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
7%21222335%464%
1817
October1st to 15thNight
11%6%3332445%6%49%
1936
16th to endNight
6%5%1442335%7%55%
2214
November1st to 15thNight
5%424324447%56%
2275
16th to endNight
45%2442345%7%54%
2439
December1st to 15thNight
5%6%45%5%3345%8%48%
2520
16th to endNight
37%35%42435%7%51%
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
46%444245%6%9%47%
1432
16th to endDay
37%344345%5%8%49%
1577
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
6%312113237%67%
1847
October1st to 15thDay
12%5%2333445%5%50%
1691
16th to endDay
5%41331335%7%58%
1647
November1st to 15thDay
45%2431436%8%53%
1583
16th to endDay
45%34323448%55%
1518
December1st to 15thDay
36%346%345%5%9%47%
1440
16th to endDay
6%7%46%324347%49%
1536
January1st to 15thNight
36%36%5%2446%7%48%
2506
16th to endNight
36%35%435%45%7%49%
2658
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
7%212223345%64%
1817
October1st to 15thNight
11%5%24324447%49%
1936
16th to endNight
6%414423347%55%
2214
November1st to 15thNight
5%32432445%7%56%
2275
16th to endNight
45%2442445%8%54%
2439
December1st to 15thNight
46%45%5%2445%7%48%
2520
16th to endNight
37%35%5%2445%8%51%
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
32%6%20%30%9%1
1433
16th to endDay
30%6%19%29%12%2
1577
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
19%210%33%29%4
1847
October1st to 15thDay
34%5%11%25%18%4
1691
16th to endDay
25%5%15%32%16%5%
1647
November1st to 15thDay
26%5%16%26%19%6%
1583
16th to endDay
26%5%17%29%17%2
1518
December1st to 15thDay
33%7%21%24%12%1
1440
16th to endDay
35%6%16%28%12%1
1536
January1st to 15thNight
32%7%17%26%14%2
2506
16th to endNight
30%7%16%29%14%2
2658
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
21%310%32%24%7%
1817
October1st to 15thNight
34%5%14%21%18%5%
1936
16th to endNight
28%5%12%28%19%6%
2214
November1st to 15thNight
26%415%24%22%6%
2275
16th to endNight
27%5%14%30%18%4
2439
December1st to 15thNight
33%7%18%27%11%2
2520
16th to endNight
31%6%19%27%12%2
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
7%18%27%23%18%3
90
16th to endDay
7%16%38%21%11%4
96
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
10%9%17%36%17%7%
112
October1st to 15thDay
5%10%28%35%17%2
90
16th to endDay
8%10%23%30%21%5%
96
November1st to 15thDay
435%33%17%8%
90
16th to endDay
24%11%35%22%6%
90
December1st to 15thDay
10%13%50%17%8%
90
16th to endDay
6%13%57%18%4
96
January1st to 15thNight
7%17%40%24%7%1
900
16th to endNight
6%20%43%23%5%
930
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
7%6%27%41%15%1
498
October1st to 15thNight
16%8%30%30%12%1
616
16th to endNight
8%7%37%34%11%
806
November1st to 15thNight
7%10%39%30%10%1
875
16th to endNight
6%12%42%31%6%
900
December1st to 15thNight
8%14%47%23%6%
900
16th to endNight
8%14%45%26%5%
960
Page generated at 2017-09-18 06:38:22. Version ac04

Copyright 2017 A. Danko


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