Pinetop Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pinetop Observatory clear sky chart from 2005-11-06 to 2024-02-10.

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
42%
23833
20%
79779
13%
23735
51%
23735
23%
49544

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 10thNight
22%
754
25%
3999
7%
737
41%
737
14%
2075
January11th to 20thNight
26%
759
27%
3955
10%
740
42%
740
13%
2174
January21st to endNight
22%
830
15%
4433
9%
814
40%
814
13%
2713
February1st to 10thNight
29%
759
20%
2464
11%
759
42%
759
21%
1542
February11th to 20thNight
16%
700
19%
2273
5%
699
34%
699
16%
1480
February21st to endNight
22%
592
24%
1711
10%
592
37%
592
20%
1128
March1st to 10thNight
29%
720
24%
1980
10%
720
43%
720
26%
1226
March11th to 20thNight
24%
720
20%
1980
8%
720
36%
720
20%
1325
March21st to endNight
29%
792
18%
2178
9%
792
37%
792
22%
1466
April1st to 10thNight
27%
720
19%
1854
5%
720
37%
720
24%
1235
April11th to 20thNight
37%
711
21%
1775
8%
711
44%
711
31%
1147
April21st to endNight
38%
667
21%
1747
9%
667
45%
667
28%
1152
May1st to 10thNight
42%
540
16%
1620
8%
540
49%
540
23%
1068
May11th to 20thNight
45%
531
13%
1592
8%
531
49%
531
22%
1113
May21st to endNight
59%
492
15%
1655
13%
492
63%
492
25%
1069
June1st to 10thNight
63%
360
18%
1440
20%
360
66%
360
25%
841
June11th to 20thNight
63%
360
15%
1440
16%
360
68%
360
23%
868
June21st to endNight
64%
360
19%
1440
19%
360
70%
360
25%
821
July1st to 10thNight
64%
499
15%
1549
14%
499
65%
499
26%
1015
July11th to 20thNight
74%
522
15%
1566
13%
522
75%
522
32%
965
July21st to endNight
71%
591
16%
1672
13%
558
72%
558
31%
1067
August1st to 10thNight
66%
537
16%
1600
14%
534
67%
534
25%
1084
August11th to 20thNight
63%
534
18%
1598
14%
534
65%
534
25%
1092
August21st to endNight
63%
787
16%
1975
11%
787
64%
787
28%
1396
September1st to 10thNight
62%
720
22%
1800
14%
720
64%
720
33%
1192
September11th to 20thNight
60%
720
26%
1908
21%
720
63%
720
32%
1225
September21st to endNight
47%
720
20%
2020
15%
720
52%
720
25%
1380
October1st to 10thNight
52%
720
19%
2160
19%
720
56%
720
27%
1372
October11th to 20thNight
44%
720
25%
2160
17%
720
55%
720
29%
1302
October21st to endNight
41%
792
28%
2376
20%
792
53%
792
30%
1405
November1st to 10thNight
45%
740
28%
2221
20%
740
56%
740
30%
1326
November11th to 20thNight
39%
760
25%
2488
16%
760
52%
760
26%
1447
November21st to endNight
38%
760
23%
2660
16%
760
50%
760
24%
1555
December1st to 10thNight
29%
760
20%
2660
10%
760
43%
760
18%
1693
December11th to 20thNight
34%
759
23%
3174
13%
758
48%
758
19%
1875
December21st to endNight
33%
825
15%
4656
11%
817
48%
817
12%
2710

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%6%35%5%35%5%6%8%42%
78365
Night
13%6%35%5%345%5%7%44%
80595
TransparencyDay
39%9%12%21%15%3
78086
Night
37%8%12%22%16%4
80393
SeeingDay
18%14%25%24%14%5%
13935
Night
16%11%25%31%15%2
23863

By Month

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 10thDay
15%7%35%6%34446%44%
2836
11th to 20thDay
13%8%38%7%35%5%5%5%39%
2840
21st to endDay
16%9%36%5%34446%40%
3124
February1st to 10thDay
11%8%37%6%35%45%6%42%
1701
11th to 20thDay
15%6%36%6%245%5%6%41%
1573
21st to endDay
15%7%35%5%446%46%41%
1540
March1st to 10thDay
12%6%25%42445%5%50%
1980
11th to 20thDay
15%7%35%5%35%5%6%6%40%
1980
21st to endDay
13%9%36%6%45%5%5%7%38%
2178
April1st to 10thDay
8%7%345%35%5%6%8%46%
2106
11th to 20thDay
12%6%25%5%345%5%7%47%
2134
21st to endDay
15%7%35%5%45%45%6%42%
2227
May1st to 10thDay
14%5%36%6%45%6%7%8%37%
2340
11th to 20thDay
16%7%35%5%36%5%5%7%36%
2301
21st to endDay
13%6%25%5%46%5%5%9%39%
2616
June1st to 10thDay
11%4245%45%6%7%9%43%
2520
11th to 20thDay
10%436%6%5%6%7%8%9%37%
2520
21st to endDay
7%435%6%35%6%8%11%43%
2520
July1st to 10thDay
10%5%26%6%37%6%6%9%39%
2359
11th to 20thDay
5%325%6%47%7%8%13%39%
2340
21st to endDay
9%6%36%6%5%7%6%9%10%33%
2547
August1st to 10thDay
9%6%35%7%46%8%8%11%33%
2327
11th to 20thDay
12%5%36%7%46%7%8%8%35%
2289
21st to endDay
10%5%25%6%35%7%7%10%40%
2376
September1st to 10thDay
12%6%35%5%35%5%5%6%47%
2160
11th to 20thDay
11%5%36%5%35%46%7%45%
2049
21st to endDay
19%6%245%346%5%7%38%
1939
October1st to 10thDay
15%5%35%43445%5%47%
1800
11th to 20thDay
15%435%32445%6%50%
1800
21st to endDay
13%5%25%4245%46%50%
1980
November1st to 10thDay
12%5%2342345%5%55%
1857
11th to 20thDay
12%6%2442445%6%50%
1684
21st to endDay
13%6%2343345%7%50%
1520
December1st to 10thDay
14%7%36%436%5%5%8%39%
1520
11th to 20thDay
14%5%24424346%53%
1910
21st to endDay
18%7%35%5%35%5%7%8%34%
2872
January1st to 10thNight
11%7%25%425%5%6%7%46%
4109
11th to 20thNight
14%8%25%43435%6%46%
4120
21st to endNight
18%9%35%424346%42%
4532
February1st to 10thNight
11%8%25%435%5%5%7%44%
2464
11th to 20thNight
17%7%35%5%245%5%7%41%
2273
21st to endNight
14%7%445%35%5%5%8%41%
1711
March1st to 10thNight
11%43443445%7%51%
1980
11th to 20thNight
17%6%25%5%3446%7%41%
1980
21st to endNight
15%7%35%5%3445%7%43%
2178
April1st to 10thNight
11%6%45%5%345%6%7%43%
1854
11th to 20thNight
11%4344246%6%8%47%
1775
21st to endNight
15%5%25%4345%5%8%45%
1747
May1st to 10thNight
14%6%35%5%35%5%5%8%42%
1620
11th to 20thNight
16%6%35%5%25%5%6%8%38%
1592
21st to endNight
13%425%436%5%6%9%42%
1654
June1st to 10thNight
10%5%344346%7%11%44%
1440
11th to 20thNight
8%5%35%6%45%6%6%8%44%
1440
21st to endNight
8%434445%6%7%10%46%
1440
July1st to 10thNight
9%5%26%6%45%6%6%9%43%
1594
11th to 20thNight
5%3235%36%7%7%12%46%
1620
21st to endNight
6%425%6%46%6%8%12%41%
1771
August1st to 10thNight
9%5%36%6%46%7%6%11%38%
1611
11th to 20thNight
10%6%35%7%45%5%6%8%41%
1598
21st to endNight
10%5%26%6%36%6%8%10%38%
1975
September1st to 10thNight
12%5%245%2445%7%48%
1800
11th to 20thNight
11%6%35%5%345%6%7%47%
1908
21st to endNight
19%7%25%434445%42%
2020
October1st to 10thNight
16%5%25%43446%7%45%
2160
11th to 20thNight
13%6%24434446%49%
2160
21st to endNight
13%4245%235%5%6%51%
2376
November1st to 10thNight
11%7%34424345%53%
2221
11th to 20thNight
11%6%25%5%2445%6%51%
2488
21st to endNight
13%5%24435%45%6%49%
2660
December1st to 10thNight
14%7%35%6%345%46%42%
2660
11th to 20thNight
14%6%35%5%3445%5%46%
3285
21st to endNight
15%6%36%5%45%6%6%7%38%
4779

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 10thDay
39%7%9%24%17%5%
2837
11th to 20thDay
45%6%9%17%18%6%
2840
21st to endDay
46%6%8%21%16%3
3124
February1st to 10thDay
43%6%10%22%16%3
1701
11th to 20thDay
42%7%11%19%17%4
1582
21st to endDay
43%8%11%16%16%6%
1540
March1st to 10thDay
36%6%10%22%22%4
1980
11th to 20thDay
43%8%11%17%16%6%
1980
21st to endDay
45%9%10%19%12%5%
2178
April1st to 10thDay
35%8%12%20%18%7%
2106
11th to 20thDay
36%8%11%21%20%5%
2134
21st to endDay
43%7%12%21%13%4
2227
May1st to 10thDay
42%12%14%17%12%2
2340
11th to 20thDay
47%10%15%19%8%2
2305
21st to endDay
42%11%16%21%9%1
2616
June1st to 10thDay
37%11%15%24%14%1
2520
11th to 20thDay
39%14%15%19%12%2
2520
21st to endDay
33%12%18%25%12%1
2520
July1st to 10thDay
40%12%13%19%13%2
2294
11th to 20thDay
32%15%19%22%10%1
2271
21st to endDay
40%14%14%20%11%1
2405
August1st to 10thDay
41%14%17%20%8%
2314
11th to 20thDay
42%13%14%20%10%1
2289
21st to endDay
37%12%19%20%9%2
2376
September1st to 10thDay
39%9%14%18%17%4
2160
11th to 20thDay
38%7%9%25%17%3
2049
21st to endDay
44%8%11%18%17%2
1939
October1st to 10thDay
37%7%10%26%14%5%
1800
11th to 20thDay
36%5%11%24%20%4
1800
21st to endDay
35%6%9%25%19%6%
1980
November1st to 10thDay
32%49%25%25%5%
1857
11th to 20thDay
35%6%11%19%21%8%
1684
21st to endDay
34%6%11%24%22%3
1520
December1st to 10thDay
43%7%12%21%14%3
1520
11th to 20thDay
32%5%10%28%18%7%
1906
21st to endDay
42%9%13%22%11%2
2872
January1st to 10thNight
33%7%12%24%20%4
4109
11th to 20thNight
38%5%10%23%19%5%
4120
21st to endNight
44%5%7%23%17%3
4532
February1st to 10thNight
38%7%12%24%16%2
2464
11th to 20thNight
43%6%9%20%16%6%
2275
21st to endNight
41%7%13%20%14%6%
1711
March1st to 10thNight
34%6%11%25%19%5%
1980
11th to 20thNight
41%7%10%20%18%4
1980
21st to endNight
41%8%12%19%15%5%
2178
April1st to 10thNight
38%8%12%20%18%5%
1854
11th to 20thNight
32%9%15%20%20%5%
1775
21st to endNight
38%8%13%24%15%3
1747
May1st to 10thNight
39%10%15%22%11%3
1620
11th to 20thNight
43%10%15%20%10%1
1593
21st to endNight
37%11%17%25%9%1
1655
June1st to 10thNight
33%11%16%27%13%
1440
11th to 20thNight
35%11%18%22%12%2
1440
21st to endNight
30%12%18%20%17%2
1440
July1st to 10thNight
37%11%15%20%13%3
1549
11th to 20thNight
28%14%20%25%12%1
1566
21st to endNight
32%12%20%24%11%
1672
August1st to 10thNight
37%14%17%22%10%1
1600
11th to 20thNight
38%12%14%23%11%1
1598
21st to endNight
38%12%17%21%8%3
1975
September1st to 10thNight
35%9%16%20%16%4
1800
11th to 20thNight
35%8%11%26%17%3
1908
21st to endNight
43%7%11%20%16%2
2020
October1st to 10thNight
39%7%12%23%17%2
2160
11th to 20thNight
35%6%10%25%20%4
2160
21st to endNight
33%6%10%23%23%4
2376
November1st to 10thNight
34%5%9%22%24%6%
2221
11th to 20thNight
35%5%9%21%24%6%
2488
21st to endNight
36%5%10%24%20%5%
2660
December1st to 10thNight
42%7%11%22%14%4
2660
11th to 20thNight
38%6%9%22%20%5%
3288
21st to endNight
39%8%12%23%15%2
4779

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 10thDay
23%33%27%13%4
270
11th to 20thDay
31%30%23%14%2
270
21st to endDay
25%29%31%14%1
297
February1st to 10thDay
23%31%31%13%3
267
11th to 20thDay
35%31%27%7%
240
21st to endDay
30%23%28%15%4
311
March1st to 10thDay
20%28%28%19%5%
420
11th to 20thDay
22%26%27%18%42
420
21st to endDay
22%22%29%20%6%1
462
April1st to 10thDay
21%24%25%20%9%1
420
11th to 20thDay
20%15%28%21%12%4
412
21st to endDay
25%16%30%19%8%3
420
May1st to 10thDay
20%21%27%21%7%4
423
11th to 20thDay
21%12%29%21%14%4
447
21st to endDay
18%5%22%27%19%9%
485
June1st to 10thDay
13%8%26%28%20%6%
450
11th to 20thDay
13%8%25%28%18%8%
450
21st to endDay
9%5%29%33%18%6%
450
July1st to 10thDay
11%5%18%28%27%11%
445
11th to 20thDay
4217%39%27%11%
444
21st to endDay
11%319%33%23%11%
488
August1st to 10thDay
13%420%26%24%13%
446
11th to 20thDay
12%5%18%28%26%13%
439
21st to endDay
11%313%35%22%16%
495
September1st to 10thDay
14%6%18%24%22%16%
450
11th to 20thDay
15%416%30%25%10%
450
21st to endDay
26%9%20%22%19%4
450
October1st to 10thDay
18%8%22%28%19%5%
450
11th to 20thDay
15%17%24%25%17%3
450
21st to endDay
17%13%33%24%10%3
495
November1st to 10thDay
18%11%28%29%11%3
455
11th to 20thDay
22%14%27%25%10%1
297
21st to endDay
22%16%32%22%7%1
180
December1st to 10thDay
23%23%32%18%31
180
11th to 20thDay
24%21%27%19%8%1
180
21st to endDay
20%26%31%16%6%
227
January1st to 10thNight
18%20%35%24%3
760
11th to 20thNight
20%18%30%28%4
760
21st to endNight
18%18%37%25%2
836
February1st to 10thNight
16%19%32%30%2
759
11th to 20thNight
24%21%34%19%1
703
21st to endNight
21%18%36%23%2
592
March1st to 10thNight
16%20%33%28%4
720
11th to 20thNight
24%18%31%20%7%1
720
21st to endNight
21%14%33%26%6%1
792
April1st to 10thNight
17%19%34%24%6%
720
11th to 20thNight
14%14%30%30%12%
711
21st to endNight
19%10%29%33%8%1
667
May1st to 10thNight
17%9%26%31%15%1
540
11th to 20thNight
19%5%24%36%15%1
531
21st to endNight
16%216%37%27%2
494
June1st to 10thNight
11%118%46%23%1
360
11th to 20thNight
8%418%42%27%1
360
21st to endNight
8%418%47%22%2
360
July1st to 10thNight
10%312%33%35%6%
499
11th to 20thNight
7%110%33%42%7%
522
21st to endNight
7%213%38%34%6%
591
August1st to 10thNight
12%211%37%35%4
537
11th to 20thNight
11%313%34%35%3
534
21st to endNight
12%212%35%34%5%
787
September1st to 10thNight
13%313%33%32%6%
720
11th to 20thNight
13%414%34%30%5%
720
21st to endNight
23%5%19%31%20%2
720
October1st to 10thNight
18%7%17%32%23%3
720
11th to 20thNight
16%10%25%33%15%1
720
21st to endNight
16%10%28%33%12%1
792
November1st to 10thNight
16%9%24%35%13%2
740
11th to 20thNight
15%15%26%34%9%1
760
21st to endNight
17%14%28%32%8%1
760
December1st to 10thNight
19%14%32%28%6%
760
11th to 20thNight
15%14%31%34%6%
760
21st to endNight
18%15%29%35%4
836
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