Rome
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Rome clear sky chart from 2005-11-06 to 2024-01-13.

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%
23830
19%
74564
12%
23774
45%
23774
21%
49713

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
15%
760
14%
2459
6%
757
25%
757
11%
1855
January11th to 20thNight
14%
732
13%
2378
6%
732
23%
732
9%
1828
January21st to endNight
18%
792
15%
2574
7%
792
29%
792
12%
1866
February1st to 10thNight
17%
720
12%
2292
5%
720
26%
720
11%
1742
February11th to 20thNight
15%
702
14%
2099
5%
700
23%
700
12%
1560
February21st to endNight
13%
592
14%
1776
5%
592
22%
592
11%
1342
March1st to 10thNight
20%
720
19%
2093
8%
720
30%
720
18%
1436
March11th to 20thNight
22%
720
17%
1980
9%
720
30%
720
18%
1416
March21st to endNight
27%
792
15%
2178
7%
792
33%
792
20%
1538
April1st to 10thNight
28%
680
20%
1940
10%
680
38%
680
25%
1278
April11th to 20thNight
33%
533
22%
1681
12%
533
43%
533
24%
1065
April21st to endNight
28%
540
19%
1620
7%
540
38%
540
22%
1105
May1st to 10thNight
33%
540
15%
1620
8%
540
39%
540
21%
1101
May11th to 20thNight
40%
531
15%
1592
9%
531
46%
531
23%
1078
May21st to endNight
57%
583
18%
1745
14%
582
60%
582
30%
1077
June1st to 10thNight
59%
540
18%
1620
15%
540
62%
540
34%
950
June11th to 20thNight
60%
540
18%
1620
15%
540
63%
540
35%
950
June21st to endNight
56%
540
18%
1620
14%
540
60%
540
35%
953
July1st to 10thNight
60%
525
15%
1575
14%
525
61%
525
29%
999
July11th to 20thNight
69%
522
19%
1566
16%
522
72%
522
36%
924
July21st to endNight
65%
591
20%
1672
17%
558
68%
558
32%
1025
August1st to 10thNight
70%
537
22%
1600
19%
534
70%
534
34%
946
August11th to 20thNight
67%
534
22%
1598
19%
534
70%
534
31%
979
August21st to endNight
69%
594
25%
1887
23%
594
71%
594
38%
1034
September1st to 10thNight
64%
688
23%
1948
18%
688
67%
688
36%
1166
September11th to 20thNight
63%
720
28%
1980
22%
720
67%
720
39%
1173
September21st to endNight
52%
720
27%
1980
19%
720
58%
720
33%
1227
October1st to 10thNight
54%
720
27%
1997
22%
720
59%
720
38%
1161
October11th to 20thNight
39%
720
25%
2160
17%
720
49%
720
28%
1335
October21st to endNight
34%
792
24%
2423
18%
792
45%
792
22%
1609
November1st to 10thNight
42%
740
25%
2406
20%
740
51%
740
27%
1407
November11th to 20thNight
30%
760
24%
2470
14%
760
43%
760
20%
1603
November21st to endNight
32%
760
20%
2470
14%
760
40%
760
19%
1650
December1st to 10thNight
21%
760
13%
2470
7%
760
29%
760
13%
1802
December11th to 20thNight
23%
759
17%
2989
9%
759
33%
759
12%
2097
December21st to endNight
17%
831
9%
4486
6%
817
27%
817
6%
3436

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
16%9%36%5%35%5%5%7%36%
74882
Night
15%9%36%5%3445%7%38%
74870
TransparencyDay
48%410%22%14%2
74605
Night
46%410%22%15%3
74666
SeeingDay
22%13%27%21%12%5%
13701
Night
20%11%25%27%15%2
23838

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
18%13%6%9%7%345%45%27%
1706
11th to 20thDay
22%15%6%9%6%44345%23%
1638
21st to endDay
19%15%6%7%5%34445%27%
1782
February1st to 10thDay
21%13%5%10%6%2444427%
1665
11th to 20thDay
19%11%5%9%5%345%45%28%
1748
21st to endDay
20%14%5%6%43435%6%31%
1480
March1st to 10thDay
18%11%45%5%2445%6%35%
1865
11th to 20thDay
20%9%47%7%345%46%32%
1980
21st to endDay
21%9%47%6%3445%6%31%
2178
April1st to 10thDay
15%9%46%5%34447%39%
2034
11th to 20thDay
18%8%35%434447%40%
2226
21st to endDay
18%9%36%6%45%5%47%35%
2340
May1st to 10thDay
20%8%36%5%45%45%7%34%
2340
11th to 20thDay
20%8%46%6%35%5%5%7%32%
2301
21st to endDay
10%6%36%6%46%6%7%9%36%
2531
June1st to 10thDay
12%5%245%36%7%6%8%41%
2340
11th to 20thDay
10%5%25%6%46%6%6%8%40%
2340
21st to endDay
10%5%25%6%45%6%7%9%39%
2340
July1st to 10thDay
13%7%26%5%37%6%5%8%38%
2340
11th to 20thDay
10%5%35%6%47%6%7%10%37%
2340
21st to endDay
12%7%35%5%35%6%7%9%39%
2547
August1st to 10thDay
10%5%26%6%36%6%7%11%38%
2327
11th to 20thDay
10%6%36%6%46%6%7%10%35%
2303
21st to endDay
9%5%25%6%35%5%7%9%45%
2466
September1st to 10thDay
15%5%24435%5%46%47%
1994
11th to 20thDay
10%425%5%345%5%7%49%
1980
21st to endDay
16%6%26%424446%46%
1980
October1st to 10thDay
13%5%145%35%46%7%48%
1962
11th to 20thDay
15%6%25%5%3445%6%46%
1800
21st to endDay
22%9%25%424336%40%
1930
November1st to 10thDay
12%7%24334346%51%
1672
11th to 20thDay
15%12%36%4235%46%39%
1710
21st to endDay
19%8%45%5%3435%6%38%
1710
December1st to 10thDay
24%13%47%6%345%45%26%
1710
11th to 20thDay
18%15%6%7%5%44446%28%
2153
21st to endDay
19%18%5%9%7%34445%20%
3124
January1st to 10thNight
17%14%5%10%6%45%445%26%
2459
11th to 20thNight
21%15%6%8%6%3434425%
2378
21st to endNight
18%12%5%9%5%44345%30%
2574
February1st to 10thNight
22%13%5%8%6%33446%26%
2292
11th to 20thNight
21%12%48%5%35%445%30%
2098
21st to endNight
24%14%5%6%6%23345%28%
1776
March1st to 10thNight
18%8%36%5%35%5%45%38%
2093
11th to 20thNight
19%9%46%425%5%5%7%33%
1980
21st to endNight
18%9%46%5%3446%6%34%
2178
April1st to 10thNight
15%8%35%5%345%6%8%39%
1940
11th to 20thNight
15%7%35%425%5%6%7%41%
1681
21st to endNight
16%8%46%5%35%45%6%38%
1620
May1st to 10thNight
18%7%35%5%345%5%9%36%
1620
11th to 20thNight
16%7%35%6%35%5%5%8%38%
1592
21st to endNight
9%425%445%6%8%10%42%
1744
June1st to 10thNight
7%425%6%35%5%7%9%47%
1620
11th to 20thNight
6%5%25%445%5%6%12%46%
1620
21st to endNight
7%4245%35%6%7%11%45%
1620
July1st to 10thNight
10%6%26%4445%6%9%44%
1620
11th to 20thNight
6%425%5%35%5%7%11%48%
1620
21st to endNight
8%5%345%35%6%7%9%45%
1771
August1st to 10thNight
7%5%25%445%6%6%9%47%
1611
11th to 20thNight
8%5%35%5%46%6%6%9%45%
1598
21st to endNight
7%5%144335%6%9%53%
1887
September1st to 10thNight
11%5%23435%5%5%8%50%
1948
11th to 20thNight
11%4235%35%346%54%
1980
21st to endNight
12%5%25%4245%5%5%48%
1980
October1st to 10thNight
10%5%244345%5%8%51%
1997
11th to 20thNight
15%6%244245%5%9%44%
2160
21st to endNight
20%8%25%5%24445%40%
2423
November1st to 10thNight
13%6%345%33445%50%
2406
11th to 20thNight
16%9%46%5%34447%40%
2470
21st to endNight
19%12%35%5%34446%37%
2470
December1st to 10thNight
23%13%5%7%434347%27%
2470
11th to 20thNight
18%11%7%8%5%34346%31%
3042
21st to endNight
20%18%6%8%7%45%445%20%
4532

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
60%39%17%11%1
1707
11th to 20thDay
65%39%17%6%
1638
21st to endDay
59%210%20%7%2
1782
February1st to 10thDay
62%39%17%8%1
1665
11th to 20thDay
59%37%19%10%2
1758
21st to endDay
56%28%21%10%3
1480
March1st to 10thDay
50%38%25%11%2
1865
11th to 20thDay
55%48%19%12%3
1980
21st to endDay
54%49%21%10%2
2178
April1st to 10thDay
46%310%25%13%3
2034
11th to 20thDay
45%38%22%17%4
2226
21st to endDay
50%411%22%10%3
2340
May1st to 10thDay
51%411%22%10%2
2340
11th to 20thDay
53%411%19%11%2
2305
21st to endDay
43%7%15%22%13%1
2531
June1st to 10thDay
40%6%11%25%17%1
2340
11th to 20thDay
40%5%14%23%15%2
2340
21st to endDay
41%6%13%23%14%3
2340
July1st to 10thDay
43%6%13%20%16%2
2275
11th to 20thDay
40%7%12%23%16%2
2271
21st to endDay
41%6%13%25%12%2
2405
August1st to 10thDay
38%7%14%27%12%1
2314
11th to 20thDay
43%6%12%26%13%1
2303
21st to endDay
36%5%15%24%17%4
2466
September1st to 10thDay
38%5%11%22%18%6%
1994
11th to 20thDay
34%5%11%25%23%2
1980
21st to endDay
41%37%26%21%2
1980
October1st to 10thDay
35%5%11%24%23%2
1962
11th to 20thDay
40%38%27%20%3
1800
21st to endDay
48%29%24%16%2
1930
November1st to 10thDay
36%39%28%21%4
1672
11th to 20thDay
47%37%22%19%4
1710
21st to endDay
48%310%22%16%2
1710
December1st to 10thDay
60%39%19%8%1
1710
11th to 20thDay
58%38%18%13%1
2150
21st to endDay
66%39%15%6%1
3124
January1st to 10thNight
61%37%17%10%1
2459
11th to 20thNight
63%38%16%8%1
2378
21st to endNight
58%39%21%8%2
2574
February1st to 10thNight
61%38%19%7%1
2292
11th to 20thNight
59%37%20%11%1
2099
21st to endNight
60%310%15%9%3
1776
March1st to 10thNight
49%36%22%17%2
2093
11th to 20thNight
51%410%22%11%2
1980
21st to endNight
50%411%21%11%2
2178
April1st to 10thNight
43%49%26%16%2
1940
11th to 20thNight
42%310%19%18%6%
1681
21st to endNight
48%411%21%14%2
1620
May1st to 10thNight
46%6%12%21%11%3
1620
11th to 20thNight
45%6%14%20%13%2
1593
21st to endNight
36%7%16%22%17%2
1745
June1st to 10thNight
33%5%16%26%17%4
1620
11th to 20thNight
32%5%16%22%21%4
1620
21st to endNight
31%7%16%26%17%3
1620
July1st to 10thNight
37%8%12%23%16%4
1575
11th to 20thNight
31%6%15%24%21%3
1566
21st to endNight
35%6%14%29%14%2
1672
August1st to 10thNight
33%6%15%28%16%2
1600
11th to 20thNight
36%7%13%25%18%1
1598
21st to endNight
29%5%14%28%19%5%
1887
September1st to 10thNight
33%413%24%18%7%
1948
11th to 20thNight
32%411%24%26%3
1980
21st to endNight
36%49%22%27%2
1980
October1st to 10thNight
31%411%27%23%4
1997
11th to 20thNight
38%49%26%20%3
2160
21st to endNight
47%37%23%17%3
2423
November1st to 10thNight
37%38%24%23%4
2406
11th to 20thNight
47%27%19%20%4
2470
21st to endNight
49%29%23%14%2
2470
December1st to 10thNight
58%310%18%10%1
2470
11th to 20thNight
56%28%22%11%1
3044
21st to endNight
67%38%15%7%
4532

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
30%24%33%10%3
270
11th to 20thDay
37%24%29%10%
246
21st to endDay
33%27%28%11%1
264
February1st to 10thDay
36%25%26%10%3
240
11th to 20thDay
39%27%30%5%
240
21st to endDay
36%23%34%6%1
198
March1st to 10thDay
35%22%30%10%2
305
11th to 20thDay
30%21%31%12%5%
420
21st to endDay
35%17%29%13%5%
462
April1st to 10thDay
29%18%27%18%8%1
420
11th to 20thDay
27%17%28%18%7%3
412
21st to endDay
26%19%32%14%6%2
420
May1st to 10thDay
26%19%30%15%8%2
423
11th to 20thDay
23%10%32%21%9%4
447
21st to endDay
16%10%24%27%15%8%
485
June1st to 10thDay
14%7%25%31%16%7%
450
11th to 20thDay
12%7%30%29%16%7%
450
21st to endDay
13%10%27%26%15%9%
450
July1st to 10thDay
14%6%17%21%22%20%
445
11th to 20thDay
9%7%22%31%20%11%
444
21st to endDay
13%5%22%28%22%11%
488
August1st to 10thDay
12%5%20%30%20%12%
446
11th to 20thDay
14%5%20%31%21%9%
439
21st to endDay
10%5%17%32%24%11%
495
September1st to 10thDay
15%5%17%25%27%10%
450
11th to 20thDay
11%418%29%28%11%
450
21st to endDay
21%7%22%27%19%4
450
October1st to 10thDay
14%6%26%30%17%6%
450
11th to 20thDay
18%14%34%20%11%3
450
21st to endDay
26%14%34%20%7%
445
November1st to 10thDay
19%14%36%21%8%2
270
11th to 20thDay
31%17%30%17%41
270
21st to endDay
27%18%35%16%31
270
December1st to 10thDay
32%20%30%11%6%
270
11th to 20thDay
26%23%33%14%3
270
21st to endDay
33%24%32%9%1
297
January1st to 10thNight
30%19%31%17%4
760
11th to 20thNight
33%18%30%16%2
732
21st to endNight
27%21%30%20%2
792
February1st to 10thNight
32%17%31%20%1
720
11th to 20thNight
32%21%29%17%1
703
21st to endNight
34%18%31%15%1
592
March1st to 10thNight
28%16%32%20%4
720
11th to 20thNight
27%17%30%19%7%1
720
21st to endNight
23%15%31%23%7%
792
April1st to 10thNight
23%14%32%23%8%
680
11th to 20thNight
20%12%32%26%10%1
533
21st to endNight
19%11%36%25%8%1
540
May1st to 10thNight
21%11%30%26%11%2
540
11th to 20thNight
19%8%25%31%15%1
531
21st to endNight
10%421%35%25%5%
584
June1st to 10thNight
7%5%21%42%22%2
540
11th to 20thNight
8%322%35%27%4
540
21st to endNight
8%5%23%34%26%3
540
July1st to 10thNight
13%215%28%32%10%
525
11th to 20thNight
6%313%39%34%5%
522
21st to endNight
9%413%37%32%5%
591
August1st to 10thNight
8%210%41%33%6%
537
11th to 20thNight
9%310%38%32%8%
534
21st to endNight
9%114%35%35%6%
594
September1st to 10thNight
13%311%31%35%7%
688
11th to 20thNight
13%315%30%32%7%
720
21st to endNight
13%6%21%33%23%3
720
October1st to 10thNight
13%6%21%30%25%4
720
11th to 20thNight
18%11%27%28%14%1
720
21st to endNight
24%13%26%26%10%1
792
November1st to 10thNight
17%12%25%28%17%1
740
11th to 20thNight
23%15%29%24%8%1
760
21st to endNight
26%13%25%26%9%1
760
December1st to 10thNight
30%19%24%22%5%
760
11th to 20thNight
25%17%30%21%6%1
760
21st to endNight
31%17%30%20%3
836
Page generated at 2024-01-10 10:16:12. Version ac07

Copyright 2024 Attilla Danko


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