This page made possible by the sponsorship of: AstrocatFreitag.

Houghton
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Houghton clear sky chart from 2005-11-05 to 2018-02-14.

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
31%
16881
10%
48825
6%
16835
34%
16835
15%
37179

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
11%
975
3%
2716
1%
970
14%
970
4%
2475
January16th to endNight
13%
1040
3%
2912
1%
1040
15%
1040
5%
2628
February1st to 15thNight
20%
950
5%
2535
2%
946
23%
946
8%
2190
February16th to endNight
25%
643
9%
1905
4%
643
29%
643
11%
1541
March1st to 15thNight
34%
720
14%
2160
10%
720
37%
720
18%
1554
March16th to endNight
38%
609
17%
2010
13%
609
44%
609
18%
1372
April1st to 15thNight
33%
539
12%
1797
8%
539
39%
539
17%
1289
April16th to endNight
36%
540
15%
1677
11%
540
41%
540
20%
1163
May1st to 15thNight
37%
540
12%
1443
8%
540
39%
540
19%
1070
May16th to endNight
46%
562
13%
1498
7%
561
49%
561
26%
1039
June1st to 15thNight
53%
540
8%
1440
5%
540
54%
540
26%
995
June16th to endNight
49%
540
8%
1440
5%
540
51%
540
25%
991
July1st to 15thNight
55%
510
10%
1360
6%
510
57%
510
35%
845
July16th to endNight
57%
564
17%
1417
10%
531
59%
531
40%
841
August1st to 15thNight
61%
539
22%
1431
15%
536
64%
536
41%
831
August16th to endNight
50%
573
17%
1854
15%
573
54%
573
30%
1077
September1st to 15thNight
53%
540
17%
1800
15%
540
57%
540
27%
1057
September16th to endNight
43%
696
14%
1959
10%
696
45%
696
26%
1303
October1st to 15thNight
33%
720
14%
2124
8%
720
38%
720
20%
1493
October16th to endNight
27%
768
9%
2481
5%
768
31%
768
11%
1927
November1st to 15thNight
23%
783
11%
2494
6%
783
29%
783
10%
1956
November16th to endNight
17%
975
7%
2730
4%
975
19%
975
7%
2376
December1st to 15thNight
9%
975
2%
2730
1%
975
11%
975
3%
2503
December16th to endNight
10%
1040
4%
2912
1%
1040
13%
1040
4%
2663

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%10%48%7%35%446%30%
49260
Night
14%11%5%9%8%45%445%26%
48992
Cloud CoverDay
14%10%48%6%35%446%31%
49270
Night
14%11%5%9%7%45%445%27%
48997
Cloud CoverDay
13%10%48%7%35%446%30%
49269
Night
13%11%5%9%8%45%445%26%
48997
TransparencyDay
54%412%20%7%
48945
Night
59%411%17%6%
48825
SeeingDay
18%8%28%27%12%3
6642
Night
20%10%27%27%12%1
16882

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
11%15%10%15%13%6%8%3327%
1552
16th to endDay
9%14%8%14%14%8%6%44310%
1664
February1st to 15thDay
8%11%6%15%13%8%9%5%4312%
1626
16th to endDay
10%15%7%13%11%5%7%5%45%14%
1567
March1st to 15thDay
10%10%5%10%11%46%45%5%25%
1790
16th to endDay
16%11%5%9%5%35%446%26%
2223
April1st to 15thDay
15%9%5%6%5%345%46%32%
2151
16th to endDay
19%8%35%5%3445%6%31%
2283
May1st to 15thDay
15%8%36%5%25%446%36%
2505
16th to endDay
11%7%36%6%45%5%5%8%36%
2617
June1st to 15thDay
13%6%244345%6%7%40%
2520
16th to endDay
13%5%25%4245%6%8%41%
2520
July1st to 15thDay
9%4244245%5%8%47%
2520
16th to endDay
7%4245%235%5%9%50%
2655
August1st to 15thDay
9%3243235%5%8%49%
2520
16th to endDay
11%5%245%2445%7%45%
2344
September1st to 15thDay
14%6%25%43435%8%42%
2160
16th to endDay
19%8%35%5%3335%6%34%
1989
October1st to 15thDay
17%13%37%5%34347%29%
1836
16th to endDay
24%19%5%9%7%3423316%
1742
November1st to 15thDay
17%19%7%9%5%3444419%
1692
16th to endDay
15%18%8%17%11%4342310%
1560
December1st to 15thDay
11%17%11%20%14%5%43334
1560
16th to endDay
17%19%11%16%10%5%6%3235%
1664
January1st to 15thNight
12%12%8%16%15%7%8%4327%
2716
16th to endNight
10%14%8%15%16%7%7%5%337%
2912
February1st to 15thNight
10%12%5%12%13%8%10%44314%
2532
16th to endNight
11%14%5%11%10%5%7%45%417%
1905
March1st to 15thNight
12%10%49%7%35%44432%
2147
16th to endNight
14%10%5%6%6%2445%7%33%
2010
April1st to 15thNight
18%9%36%5%45%445%29%
1797
16th to endNight
20%10%35%424446%33%
1677
May1st to 15thNight
19%7%46%6%35%45%5%29%
1443
16th to endNight
12%6%26%5%36%5%6%7%36%
1496
June1st to 15thNight
15%5%35%5%36%5%6%6%36%
1440
16th to endNight
14%5%35%5%35%6%5%8%35%
1440
July1st to 15thNight
10%424435%45%8%45%
1440
16th to endNight
7%3234345%7%9%48%
1513
August1st to 15thNight
7%32343346%7%52%
1440
16th to endNight
12%6%15%423447%47%
1854
September1st to 15thNight
11%6%35%5%24446%45%
1800
16th to endNight
17%7%35%5%33346%40%
1959
October1st to 15thNight
19%9%26%43435%5%34%
2124
16th to endNight
20%16%47%5%3444422%
2481
November1st to 15thNight
16%18%5%8%6%34445%22%
2494
16th to endNight
18%16%7%15%9%3433413%
2730
December1st to 15thNight
13%17%9%21%12%443237%
2730
16th to endNight
13%20%10%15%11%5%5%3237%
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
10%14%11%15%12%7%8%4328%
1552
16th to endDay
9%14%8%14%13%8%7%5%3311%
1664
February1st to 15thDay
8%11%7%14%14%8%9%45%412%
1626
16th to endDay
10%15%7%12%10%5%7%445%14%
1567
March1st to 15thDay
11%10%6%9%9%46%445%25%
1800
16th to endDay
16%11%5%8%6%35%446%27%
2223
April1st to 15thDay
15%10%46%5%3445%5%33%
2151
16th to endDay
19%9%36%433446%31%
2283
May1st to 15thDay
16%8%35%6%25%446%36%
2505
16th to endDay
12%7%35%5%45%45%7%36%
2617
June1st to 15thDay
14%5%25%5%3446%7%41%
2520
16th to endDay
14%4244245%6%7%41%
2520
July1st to 15thDay
10%424425%45%8%48%
2520
16th to endDay
8%31442445%9%49%
2655
August1st to 15thDay
10%325%32445%8%50%
2520
16th to endDay
12%5%245%34447%45%
2344
September1st to 15thDay
16%5%25%433347%43%
2160
16th to endDay
20%7%25%6%33347%34%
1989
October1st to 15thDay
18%12%36%5%35%347%30%
1836
16th to endDay
24%20%48%6%3423416%
1742
November1st to 15thDay
17%20%5%7%5%35%44420%
1692
16th to endDay
15%18%8%16%9%45%33310%
1560
December1st to 15thDay
11%18%10%19%13%45%3345%
1560
16th to endDay
17%19%11%15%9%5%6%3236%
1664
January1st to 15thNight
12%12%8%16%13%7%8%4338%
2716
16th to endNight
10%13%8%13%15%7%7%5%348%
2912
February1st to 15thNight
10%11%5%11%12%8%9%5%4315%
2525
16th to endNight
11%14%412%10%5%7%5%4419%
1905
March1st to 15thNight
12%10%38%7%45%5%5%432%
2160
16th to endNight
14%10%46%5%3445%6%33%
2010
April1st to 15thNight
18%9%36%5%35%446%30%
1797
16th to endNight
20%10%26%324446%33%
1677
May1st to 15thNight
21%6%36%6%35%5%5%5%30%
1442
16th to endNight
13%5%36%6%35%5%6%6%37%
1496
June1st to 15thNight
16%425%437%5%5%7%37%
1440
16th to endNight
15%5%25%5%36%5%5%8%36%
1440
July1st to 15thNight
10%4245%25%45%8%46%
1440
16th to endNight
7%314335%5%6%9%49%
1513
August1st to 15thNight
8%31342447%7%52%
1440
16th to endNight
13%5%14423347%48%
1854
September1st to 15thNight
11%6%34433446%46%
1800
16th to endNight
17%6%35%5%23346%40%
1959
October1st to 15thNight
20%8%35%5%3445%5%35%
2124
16th to endNight
21%16%37%6%34445%23%
2481
November1st to 15thNight
17%17%5%6%6%35%436%23%
2494
16th to endNight
17%16%7%13%9%35%33414%
2730
December1st to 15thNight
13%17%9%19%12%45%3248%
2730
16th to endNight
13%20%10%15%10%46%4338%
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
10%14%10%15%12%7%8%5%327%
1552
16th to endDay
9%13%7%15%15%7%7%44410%
1664
February1st to 15thDay
7%11%5%14%14%7%8%6%4412%
1626
16th to endDay
10%16%7%12%11%5%7%5%45%14%
1567
March1st to 15thDay
11%10%5%10%10%5%6%5%45%24%
1800
16th to endDay
15%11%5%8%6%35%446%27%
2222
April1st to 15thDay
13%11%46%435%5%5%5%32%
2151
16th to endDay
18%9%35%5%245%47%32%
2283
May1st to 15thDay
15%8%45%6%24446%36%
2505
16th to endDay
11%7%46%5%35%45%8%36%
2617
June1st to 15thDay
13%5%2443445%8%40%
2520
16th to endDay
13%5%245%345%6%7%41%
2520
July1st to 15thDay
9%425%32446%8%48%
2520
16th to endDay
7%4244344410%49%
2655
August1st to 15thDay
8%4234235%5%8%50%
2520
16th to endDay
11%5%24425%45%7%45%
2344
September1st to 15thDay
13%7%245%2435%7%42%
2160
16th to endDay
18%8%26%5%33446%35%
1989
October1st to 15thDay
16%12%37%5%34347%30%
1836
16th to endDay
23%18%5%10%7%3433316%
1742
November1st to 15thDay
17%19%6%9%5%35%44420%
1692
16th to endDay
15%18%8%15%11%4433310%
1560
December1st to 15thDay
11%17%10%19%14%5%5%3334
1560
16th to endDay
16%18%10%15%11%5%6%3235%
1664
January1st to 15thNight
13%11%7%15%14%8%9%5%427%
2716
16th to endNight
9%13%9%14%15%7%8%6%438%
2912
February1st to 15thNight
9%11%6%10%13%8%10%5%4415%
2525
16th to endNight
11%14%6%10%10%5%7%46%417%
1905
March1st to 15thNight
11%10%47%7%45%5%45%33%
2160
16th to endNight
13%10%5%6%6%34446%34%
2010
April1st to 15thNight
18%9%36%6%46%45%5%30%
1797
16th to endNight
20%9%35%5%24446%34%
1677
May1st to 15thNight
19%7%37%7%4445%5%29%
1442
16th to endNight
13%5%26%6%35%6%6%6%37%
1496
June1st to 15thNight
14%5%25%445%6%6%8%35%
1440
16th to endNight
13%6%25%5%36%6%5%8%35%
1440
July1st to 15thNight
9%4245%25%45%9%45%
1440
16th to endNight
7%324325%47%9%49%
1513
August1st to 15thNight
7%32342436%7%52%
1440
16th to endNight
12%6%14423446%47%
1854
September1st to 15thNight
9%7%35%43345%6%46%
1800
16th to endNight
16%6%36%5%3335%7%40%
1959
October1st to 15thNight
17%9%36%5%34445%34%
2124
16th to endNight
19%16%47%6%35%346%22%
2481
November1st to 15thNight
16%17%6%8%6%34445%22%
2494
16th to endNight
17%16%7%13%9%45%33413%
2730
December1st to 15thNight
13%16%9%19%12%45%3337%
2730
16th to endNight
13%18%10%15%10%5%5%4338%
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
82%35%7%1
1553
16th to endDay
78%47%8%1
1664
February1st to 15thDay
74%311%9%1
1627
16th to endDay
71%5%7%12%3
1567
March1st to 15thDay
59%411%14%8%
1800
16th to endDay
57%412%18%5%1
2223
April1st to 15thDay
50%5%10%20%11%1
2151
16th to endDay
51%49%22%9%1
2283
May1st to 15thDay
48%312%22%11%1
2505
16th to endDay
45%412%24%12%
2621
June1st to 15thDay
41%316%26%11%
2520
16th to endDay
39%5%17%27%9%1
2520
July1st to 15thDay
33%313%33%14%1
2371
16th to endDay
30%415%31%16%
2488
August1st to 15thDay
30%5%17%33%12%
2505
16th to endDay
36%418%27%12%
2344
September1st to 15thDay
40%317%30%8%
2160
16th to endDay
49%417%23%5%
1989
October1st to 15thDay
54%313%22%5%
1836
16th to endDay
73%39%9%3
1742
November1st to 15thDay
67%310%13%4
1692
16th to endDay
80%37%5%2
1560
December1st to 15thDay
85%36%3
1560
16th to endDay
85%25%5%
1664
January1st to 15thNight
83%27%6%
2716
16th to endNight
80%48%6%
2912
February1st to 15thNight
74%311%10%
2535
16th to endNight
67%310%14%3
1905
March1st to 15thNight
52%412%19%10%
2160
16th to endNight
50%412%21%10%1
2010
April1st to 15thNight
54%5%9%20%9%1
1797
16th to endNight
51%38%22%13%
1677
May1st to 15thNight
54%49%19%10%1
1443
16th to endNight
45%5%11%24%13%
1498
June1st to 15thNight
45%411%23%13%1
1440
16th to endNight
44%5%15%21%12%
1440
July1st to 15thNight
35%413%32%14%
1360
16th to endNight
29%5%15%32%14%2
1417
August1st to 15thNight
28%417%34%12%2
1431
16th to endNight
36%316%26%14%2
1854
September1st to 15thNight
38%314%31%11%
1800
16th to endNight
45%317%28%4
1959
October1st to 15thNight
51%314%22%8%
2124
16th to endNight
63%313%13%5%
2481
November1st to 15thNight
64%410%14%5%
2494
16th to endNight
75%49%7%2
2730
December1st to 15thNight
83%36%5%
2730
16th to endNight
83%36%5%
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
17%13%31%31%5%
135
16th to endDay
19%11%32%26%9%1
144
February1st to 15thDay
17%22%37%18%3
130
16th to endDay
25%14%30%20%7%
81
March1st to 15thDay
11%17%36%23%7%3
90
16th to endDay
27%9%24%24%10%3
231
April1st to 15thDay
24%7%24%32%9%1
270
16th to endDay
29%5%24%22%13%4
270
May1st to 15thDay
19%11%33%24%8%2
462
16th to endDay
19%8%30%26%11%3
517
June1st to 15thDay
17%7%31%28%11%3
495
16th to endDay
17%6%29%27%14%4
495
July1st to 15thDay
13%426%33%17%4
475
16th to endDay
8%6%29%32%16%5%
515
August1st to 15thDay
14%5%23%33%17%6%
493
16th to endDay
18%421%30%19%6%
346
September1st to 15thDay
18%421%25%24%6%
315
16th to endDay
19%7%25%27%15%3
314
October1st to 15thDay
21%9%28%26%12%1
171
16th to endDay
39%11%27%18%3
144
November1st to 15thDay
25%20%28%17%6%1
135
16th to endDay
25%20%28%17%7%1
135
December1st to 15thDay
25%10%38%19%5%
135
16th to endDay
18%22%40%15%2
144
January1st to 15thNight
19%15%37%21%5%
975
16th to endNight
16%15%37%21%6%1
1040
February1st to 15thNight
15%16%33%26%7%1
950
16th to endNight
19%9%32%26%10%1
643
March1st to 15thNight
17%12%27%30%11%1
720
16th to endNight
18%10%24%30%13%2
609
April1st to 15thNight
23%6%28%31%7%1
539
16th to endNight
25%425%28%13%2
540
May1st to 15thNight
22%6%26%30%12%2
540
16th to endNight
17%323%35%17%2
563
June1st to 15thNight
18%417%42%16%1
540
16th to endNight
17%418%39%17%2
540
July1st to 15thNight
10%5%22%36%22%2
510
16th to endNight
11%222%38%23%1
564
August1st to 15thNight
10%120%34%30%2
539
16th to endNight
16%422%30%23%1
573
September1st to 15thNight
16%5%17%29%25%5%
540
16th to endNight
21%5%22%33%15%1
696
October1st to 15thNight
26%9%25%25%13%
720
16th to endNight
31%10%21%25%9%
768
November1st to 15thNight
25%15%26%24%7%
783
16th to endNight
25%15%30%22%6%
975
December1st to 15thNight
21%18%34%18%5%
975
16th to endNight
23%13%33%21%7%1
1040
Page generated at 2018-02-15 10:58:47. Version ac04

Copyright 2018 A. Danko


Houghton Clear Sky Chart |Charts Home