Carranza Field
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Carranza Field clear sky chart from 2005-11-05 to 2017-08-12.

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
37%
14982
20%
46494
11%
14951
48%
14951
25%
29088

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
28%
719
22%
2506
10%
716
44%
716
20%
1538
January16th to endNight
22%
768
22%
2545
8%
768
41%
768
23%
1555
February1st to 15thNight
20%
704
19%
2228
6%
701
36%
701
22%
1394
February16th to endNight
21%
631
26%
1893
10%
631
43%
631
24%
1162
March1st to 15thNight
25%
720
21%
2125
10%
720
39%
720
26%
1331
March16th to endNight
26%
768
21%
2010
9%
768
36%
768
26%
1364
April1st to 15thNight
25%
718
19%
1796
5%
718
32%
718
28%
1196
April16th to endNight
35%
720
19%
1800
7%
720
40%
720
29%
1215
May1st to 15thNight
32%
533
17%
1613
8%
533
40%
533
21%
1092
May16th to endNight
47%
374
15%
1497
12%
374
53%
374
18%
936
June1st to 15thNight
48%
360
15%
1440
15%
360
56%
360
20%
895
June16th to endNight
57%
360
16%
1440
19%
360
62%
360
26%
808
July1st to 15thNight
59%
340
12%
1360
17%
340
60%
340
20%
835
July16th to endNight
65%
379
16%
1421
17%
357
70%
357
26%
792
August1st to 15thNight
65%
599
19%
1647
13%
596
66%
596
35%
1009
August16th to endNight
62%
700
17%
1750
9%
700
64%
700
35%
1139
September1st to 15thNight
56%
660
26%
1650
15%
660
60%
660
36%
1059
September16th to endNight
57%
657
26%
1794
21%
657
60%
657
33%
1123
October1st to 15thNight
46%
660
24%
1948
19%
660
54%
660
29%
1205
October16th to endNight
36%
704
26%
2167
15%
704
51%
704
30%
1288
November1st to 15thNight
36%
700
24%
2277
15%
700
50%
700
26%
1363
November16th to endNight
32%
720
21%
2379
13%
720
44%
720
22%
1496
December1st to 15thNight
25%
720
18%
2520
8%
720
39%
720
19%
1601
December16th to endNight
22%
768
21%
2688
7%
768
40%
768
19%
1692

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
14%5%2442445%7%41%
47481
Night
15%5%24424447%43%
46665
Cloud CoverDay
14%5%2443445%7%41%
47490
Night
15%5%2442445%7%43%
46671
TransparencyDay
41%411%23%16%2
47170
Night
40%411%23%17%3
46494
SeeingDay
18%8%25%25%15%6%
5658
Night
18%8%28%31%11%1
14984

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
13%6%35%425%445%43%
1432
16th to endDay
16%6%2342335%5%44%
1677
February1st to 15thDay
15%6%35%32445%6%41%
1631
16th to endDay
13%7%36%5%335%5%5%41%
1580
March1st to 15thDay
16%6%15%5%3445%6%41%
1823
16th to endDay
19%5%34424445%42%
2214
April1st to 15thDay
17%6%24324347%43%
2152
16th to endDay
15%42442446%8%42%
2160
May1st to 15thDay
18%5%245%3435%7%38%
2348
16th to endDay
15%5%245%3446%7%40%
2618
June1st to 15thDay
13%5%35%5%35%5%5%8%37%
2520
16th to endDay
10%425%5%36%6%6%9%38%
2520
July1st to 15thDay
9%6%35%6%36%5%6%9%36%
2520
16th to endDay
8%425%6%37%7%7%10%34%
2649
August1st to 15thDay
10%5%25%6%25%46%8%40%
2205
16th to endDay
13%5%245%25%47%9%39%
2100
September1st to 15thDay
13%5%1443345%6%46%
1980
16th to endDay
14%6%25%5%24347%40%
1834
October1st to 15thDay
17%6%24422446%44%
1680
16th to endDay
17%423323327%48%
1703
November1st to 15thDay
18%5%24422346%46%
1581
16th to endDay
16%424334345%46%
1578
December1st to 15thDay
17%5%344145%46%42%
1440
16th to endDay
21%6%3441345%6%39%
1536
January1st to 15thNight
17%5%2442335%6%42%
2506
16th to endNight
17%6%24324447%42%
2545
February1st to 15thNight
15%7%35%42435%6%41%
2227
16th to endNight
16%5%14423445%46%
1893
March1st to 15thNight
18%5%15%323347%45%
2112
16th to endNight
18%6%3442333445%
2010
April1st to 15thNight
16%6%24324345%45%
1796
16th to endNight
16%5%2442445%7%42%
1800
May1st to 15thNight
19%7%25%424447%36%
1613
16th to endNight
16%6%25%4345%47%39%
1495
June1st to 15thNight
14%6%25%426%5%47%39%
1440
16th to endNight
7%4345%35%5%6%9%43%
1440
July1st to 15thNight
9%6%26%5%346%6%11%37%
1440
16th to endNight
6%4245%46%5%7%11%42%
1517
August1st to 15thNight
7%425%5%35%5%5%8%46%
1658
16th to endNight
10%5%25%4345%6%7%44%
1750
September1st to 15thNight
13%5%235%23438%47%
1650
16th to endNight
14%6%23323347%47%
1794
October1st to 15thNight
17%5%23423346%46%
1948
16th to endNight
16%5%12423336%49%
2167
November1st to 15thNight
15%6%25%313345%48%
2277
16th to endNight
15%7%25%5%2446%6%40%
2379
December1st to 15thNight
19%5%35%42445%6%38%
2520
16th to endNight
18%6%35%424446%39%
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
13%6%35%435%446%43%
1432
16th to endDay
16%6%25%324345%44%
1677
February1st to 15thDay
15%7%35%324446%41%
1631
16th to endDay
13%7%36%5%3445%6%40%
1580
March1st to 15thDay
16%5%245%3435%6%41%
1833
16th to endDay
18%5%24423346%42%
2213
April1st to 15thDay
17%6%34323346%43%
2152
16th to endDay
15%4343245%5%7%42%
2160
May1st to 15thDay
18%5%245%245%47%39%
2348
16th to endDay
15%5%244345%5%7%40%
2618
June1st to 15thDay
13%6%25%5%35%5%5%8%37%
2520
16th to endDay
10%4246%46%6%7%8%39%
2520
July1st to 15thDay
9%5%35%6%36%5%6%8%37%
2520
16th to endDay
8%5%25%6%46%6%8%9%34%
2649
August1st to 15thDay
10%5%25%6%346%5%8%40%
2205
16th to endDay
12%5%24435%5%7%8%40%
2100
September1st to 15thDay
12%6%2443435%7%45%
1980
16th to endDay
15%6%26%5%24447%40%
1834
October1st to 15thDay
18%5%14422346%44%
1680
16th to endDay
16%424233336%48%
1703
November1st to 15thDay
17%5%24422337%45%
1581
16th to endDay
16%324424446%46%
1578
December1st to 15thDay
16%5%25%42445%6%42%
1440
16th to endDay
20%6%24323447%39%
1536
January1st to 15thNight
17%5%2432336%6%42%
2506
16th to endNight
17%6%2432445%6%43%
2545
February1st to 15thNight
15%8%2442345%6%42%
2220
16th to endNight
16%424424445%46%
1893
March1st to 15thNight
18%5%24422347%45%
2125
16th to endNight
18%6%3442432444%
2010
April1st to 15thNight
16%6%24424335%44%
1796
16th to endNight
17%4245%2445%6%42%
1800
May1st to 15thNight
19%6%35%424448%36%
1613
16th to endNight
16%7%25%424447%39%
1495
June1st to 15thNight
14%5%35%5%25%447%40%
1440
16th to endNight
7%425%5%35%6%6%10%42%
1440
July1st to 15thNight
8%5%26%5%45%6%5%11%36%
1440
16th to endNight
6%4346%46%47%10%42%
1517
August1st to 15thNight
7%425%435%5%5%8%46%
1658
16th to endNight
10%425%5%345%6%7%44%
1750
September1st to 15thNight
13%5%144235%37%47%
1650
16th to endNight
14%6%2432335%8%46%
1794
October1st to 15thNight
18%424323447%45%
1948
16th to endNight
16%5%13323345%49%
2167
November1st to 15thNight
15%5%25%32334448%
2277
16th to endNight
15%7%25%5%245%5%6%40%
2379
December1st to 15thNight
19%5%25%5%2445%6%38%
2520
16th to endNight
17%6%2442435%6%40%
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
42%313%21%14%4
1433
16th to endDay
41%210%25%15%3
1677
February1st to 15thDay
42%410%25%14%2
1634
16th to endDay
44%39%26%13%2
1580
March1st to 15thDay
43%313%23%13%2
1833
16th to endDay
42%38%23%17%3
2214
April1st to 15thDay
41%310%24%14%5%
2152
16th to endDay
39%410%19%22%4
2160
May1st to 15thDay
43%411%22%15%2
2348
16th to endDay
40%6%14%24%12%1
2622
June1st to 15thDay
43%6%13%23%11%1
2520
16th to endDay
39%7%13%22%15%2
2520
July1st to 15thDay
42%5%10%24%14%2
2371
16th to endDay
39%7%12%26%11%2
2482
August1st to 15thDay
38%6%13%23%16%1
2192
16th to endDay
37%5%13%21%19%2
2100
September1st to 15thDay
36%413%19%22%2
1980
16th to endDay
44%37%19%23%2
1834
October1st to 15thDay
40%311%24%18%2
1680
16th to endDay
38%29%27%20%2
1703
November1st to 15thDay
40%210%25%18%2
1581
16th to endDay
39%39%27%17%2
1578
December1st to 15thDay
41%316%23%12%2
1440
16th to endDay
45%214%22%13%1
1536
January1st to 15thNight
42%311%21%16%4
2506
16th to endNight
41%310%27%15%1
2545
February1st to 15thNight
42%211%24%15%3
2228
16th to endNight
38%39%24%19%4
1893
March1st to 15thNight
40%312%23%16%3
2125
16th to endNight
45%29%20%18%4
2010
April1st to 15thNight
41%210%22%17%4
1796
16th to endNight
41%49%18%22%3
1800
May1st to 15thNight
47%48%20%16%2
1613
16th to endNight
44%5%13%17%15%2
1497
June1st to 15thNight
43%6%11%20%17%
1440
16th to endNight
35%5%15%24%16%2
1440
July1st to 15thNight
41%7%15%20%13%2
1360
16th to endNight
33%7%17%27%12%1
1421
August1st to 15thNight
34%5%14%23%20%1
1647
16th to endNight
37%414%20%20%2
1750
September1st to 15thNight
36%412%23%21%2
1650
16th to endNight
36%47%24%24%2
1794
October1st to 15thNight
39%410%24%17%3
1948
16th to endNight
36%39%27%20%3
2167
November1st to 15thNight
38%39%22%19%6%
2277
16th to endNight
43%310%23%15%3
2379
December1st to 15thNight
46%313%22%13%1
2520
16th to endNight
44%312%23%13%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
16%21%38%13%8%1
60
16th to endDay
26%18%29%21%3
87
February1st to 15thDay
20%22%36%19%2
147
16th to endDay
16%19%38%22%3
239
March1st to 15thDay
21%13%31%26%6%
270
16th to endDay
21%13%34%22%43
288
April1st to 15thDay
24%9%34%20%9%2
270
16th to endDay
20%6%31%22%13%4
270
May1st to 15thDay
28%14%26%15%12%3
288
16th to endDay
21%320%30%18%5%
331
June1st to 15thDay
17%6%24%28%17%5%
315
16th to endDay
14%426%32%15%6%
315
July1st to 15thDay
16%317%32%23%6%
305
16th to endDay
11%216%33%27%9%
326
August1st to 15thDay
12%118%31%25%10%
297
16th to endDay
11%10%28%29%19%
268
September1st to 15thDay
13%421%22%19%18%
255
16th to endDay
20%218%27%16%13%
254
October1st to 15thDay
22%5%17%29%18%6%
255
16th to endDay
14%9%31%25%15%2
261
November1st to 15thDay
20%9%25%26%16%1
235
16th to endDay
17%12%35%18%13%2
198
December1st to 15thDay
18%16%35%16%11%1
60
16th to endDay
37%9%37%14%1
64
January1st to 15thNight
20%13%31%28%4
720
16th to endNight
22%11%38%25%2
768
February1st to 15thNight
19%15%38%24%
704
16th to endNight
20%16%37%23%2
631
March1st to 15thNight
23%11%35%24%4
720
16th to endNight
21%9%35%24%7%1
768
April1st to 15thNight
19%12%38%24%5%
718
16th to endNight
19%6%33%32%7%
720
May1st to 15thNight
22%7%33%27%8%
533
16th to endNight
19%320%39%16%
375
June1st to 15thNight
17%321%41%15%
360
16th to endNight
8%221%48%18%
360
July1st to 15thNight
12%116%49%19%
340
16th to endNight
8%114%46%25%2
379
August1st to 15thNight
9%212%48%25%2
599
16th to endNight
13%112%39%29%3
700
September1st to 15thNight
16%216%37%23%3
660
16th to endNight
19%313%35%24%3
657
October1st to 15thNight
20%5%21%32%18%2
660
16th to endNight
18%8%31%29%10%
704
November1st to 15thNight
18%9%29%27%13%2
700
16th to endNight
18%10%30%29%9%1
720
December1st to 15thNight
23%9%33%22%9%1
720
16th to endNight
20%12%38%24%3
768
Page generated at 2017-08-13 14:16:50. Version ac04

Copyright 2017 A. Danko


Carranza Field Clear Sky Chart | Charts Home