Jeanerette
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Jeanerette 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 Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(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

By Month

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 Forecast	Data Points
Cloud Cover	Day	11% 6% 3 6% 6% 4 6% 6% 6% 8% 39%	78909
	Night	11% 6% 2 5% 5% 3 4 5% 6% 8% 47%	80088
Transparency	Day	39% 10% 13% 18% 15% 6%	78639
	Night	34% 8% 14% 19% 17% 8%	79879
Seeing	Day	12% 5% 18% 25% 25% 15%	13760
	Night	12% 5% 19% 31% 26% 7%	23640

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	17% 7% 3 6% 6% 3 5% 5% 6% 7% 37%	2847
	11th to 20th	Day	12% 6% 2 5% 4 3 3 3 3 5% 55%	2850
	21st to end	Day	22% 9% 4 6% 5% 3 4 5% 4 6% 33%	3136
February	1st to 10th	Day	16% 9% 3 7% 5% 3 4 4 5% 6% 37%	1890
	11th to 20th	Day	17% 8% 3 5% 5% 3 4 4 5% 6% 41%	1748
	21st to end	Day	17% 9% 3 5% 5% 3 3 5% 5% 7% 38%	1547
March	1st to 10th	Day	13% 7% 2 6% 6% 3 5% 4 5% 7% 41%	1980
	11th to 20th	Day	12% 6% 3 7% 6% 3 5% 5% 6% 7% 39%	1980
	21st to end	Day	9% 5% 3 6% 4 3 4 5% 5% 7% 48%	2189
April	1st to 10th	Day	11% 5% 2 5% 6% 4 4 5% 7% 9% 43%	2160
	11th to 20th	Day	14% 6% 2 5% 6% 4 5% 5% 6% 9% 38%	2134
	21st to end	Day	8% 5% 2 5% 5% 3 6% 6% 6% 9% 46%	2160
May	1st to 10th	Day	7% 5% 3 5% 6% 3 5% 5% 7% 10% 45%	2160
	11th to 20th	Day	8% 4 3 6% 6% 4 5% 6% 6% 10% 44%	2124
	21st to end	Day	6% 5% 3 5% 6% 4 7% 7% 8% 11% 38%	2337
June	1st to 10th	Day	7% 4 2 7% 8% 5% 7% 7% 10% 11% 31%	2309
	11th to 20th	Day	5% 4 2 7% 7% 6% 8% 7% 9% 11% 34%	2340
	21st to end	Day	7% 6% 4 7% 9% 6% 9% 9% 9% 10% 24%	2340
July	1st to 10th	Day	7% 6% 4 8% 8% 6% 9% 9% 9% 10% 23%	2340
	11th to 20th	Day	8% 6% 3 9% 9% 6% 10% 7% 8% 10% 25%	2340
	21st to end	Day	8% 6% 4 9% 8% 5% 10% 9% 7% 10% 24%	2484
August	1st to 10th	Day	5% 5% 3 7% 8% 5% 7% 8% 11% 13% 29%	2148
	11th to 20th	Day	9% 5% 2 7% 8% 5% 8% 8% 10% 11% 27%	2125
	21st to end	Day	10% 7% 3 7% 8% 6% 8% 7% 7% 8% 29%	2376
September	1st to 10th	Day	10% 5% 3 6% 8% 5% 7% 7% 8% 8% 33%	2160
	11th to 20th	Day	11% 7% 3 7% 7% 5% 7% 5% 6% 7% 35%	2160
	21st to end	Day	9% 6% 2 6% 6% 3 5% 4 6% 7% 46%	1934
October	1st to 10th	Day	5% 4 2 5% 6% 2 4 5% 6% 6% 54%	1800
	11th to 20th	Day	7% 5% 3 5% 4 2 5% 4 5% 9% 52%	1800
	21st to end	Day	11% 5% 3 4 5% 2 4 4 5% 6% 52%	1980
November	1st to 10th	Day	8% 5% 2 5% 4 3 4 5% 7% 7% 51%	1858
	11th to 20th	Day	11% 5% 2 5% 4 3 4 4 5% 5% 53%	1900
	21st to end	Day	12% 6% 2 5% 5% 3 4 5% 5% 7% 46%	1900
December	1st to 10th	Day	14% 6% 3 5% 5% 3 4 5% 5% 7% 44%	1900
	11th to 20th	Day	14% 7% 3 6% 6% 4 5% 5% 5% 7% 37%	2338
	21st to end	Day	15% 7% 3 5% 5% 3 5% 5% 5% 7% 40%	3135
January	1st to 10th	Night	16% 6% 4 5% 4 3 4 4 4 6% 44%	4108
	11th to 20th	Night	14% 6% 2 4 4 2 3 3 4 6% 52%	4120
	21st to end	Night	24% 8% 2 5% 5% 2 3 4 4 7% 37%	4527
February	1st to 10th	Night	14% 7% 4 5% 6% 3 5% 4 4 6% 41%	2275
	11th to 20th	Night	17% 7% 3 6% 5% 2 3 4 5% 6% 43%	2098
	21st to end	Night	17% 9% 2 5% 4 3 4 5% 4 7% 40%	1722
March	1st to 10th	Night	12% 7% 3 5% 5% 3 4 4 5% 8% 45%	1980
	11th to 20th	Night	12% 6% 3 6% 5% 4 4 6% 6% 7% 41%	1980
	21st to end	Night	9% 5% 3 4 4 2 3 4 5% 8% 53%	2165
April	1st to 10th	Night	13% 5% 2 4 4 3 4 5% 5% 9% 45%	1800
	11th to 20th	Night	12% 6% 2 6% 5% 3 4 4 4 6% 50%	1775
	21st to end	Night	6% 4 2 5% 4 3 4 5% 6% 9% 52%	1800
May	1st to 10th	Night	9% 4 2 4 4 3 4 5% 6% 9% 51%	1800
	11th to 20th	Night	6% 4 2 4 4 3 5% 5% 7% 9% 51%	1769
	21st to end	Night	5% 3 1 4 4 3 4 5% 5% 10% 53%	1938
June	1st to 10th	Night	5% 4 2 5% 5% 3 5% 7% 7% 10% 47%	1645
	11th to 20th	Night	3 3 2 4 5% 4 6% 7% 8% 12% 47%	1620
	21st to end	Night	7% 5% 3 5% 6% 3 6% 7% 9% 12% 38%	1620
July	1st to 10th	Night	5% 6% 2 5% 5% 3 5% 7% 9% 11% 42%	1620
	11th to 20th	Night	4 4 2 5% 5% 4 5% 6% 8% 14% 43%	1620
	21st to end	Night	4 4 2 4 7% 3 5% 6% 8% 14% 43%	1830
August	1st to 10th	Night	2 2 1 3 4 3 4 5% 7% 14% 53%	1790
	11th to 20th	Night	4 3 2 5% 6% 3 7% 7% 9% 15% 40%	1776
	21st to end	Night	7% 4 3 6% 6% 4 5% 7% 8% 10% 40%	1980
September	1st to 10th	Night	5% 5% 3 5% 5% 4 5% 6% 8% 11% 43%	1800
	11th to 20th	Night	9% 6% 3 6% 5% 3 6% 5% 6% 9% 41%	1800
	21st to end	Night	6% 5% 2 5% 5% 2 3 5% 6% 7% 53%	2002
October	1st to 10th	Night	5% 3 2 4 5% 2 4 4 4 6% 59%	2160
	11th to 20th	Night	7% 4 2 3 3 2 3 4 5% 7% 59%	2160
	21st to end	Night	10% 5% 2 4 4 2 3 4 4 6% 58%	2376
November	1st to 10th	Night	8% 5% 2 5% 4 2 3 4 5% 6% 56%	2220
	11th to 20th	Night	10% 5% 2 5% 4 2 4 4 4 7% 55%	2280
	21st to end	Night	13% 6% 3 5% 4 3 4 5% 5% 7% 47%	2280
December	1st to 10th	Night	14% 6% 4 6% 5% 3 3 3 4 7% 46%	2280
	11th to 20th	Night	11% 9% 2 5% 5% 3 4 4 5% 7% 42%	2840
	21st to end	Night	17% 10% 3 6% 4 3 3 3 4 5% 40%	4532

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	43% 7% 7% 15% 19% 9%	2848
	11th to 20th	Day	32% 5% 5% 19% 30% 9%	2850
	21st to end	Day	52% 5% 6% 13% 18% 6%	3136
February	1st to 10th	Day	47% 6% 9% 13% 17% 8%	1890
	11th to 20th	Day	43% 6% 8% 16% 16% 10%	1758
	21st to end	Day	43% 8% 12% 14% 15% 7%	1547
March	1st to 10th	Day	41% 7% 9% 19% 17% 6%	1980
	11th to 20th	Day	41% 9% 13% 13% 19% 6%	1980
	21st to end	Day	33% 7% 13% 22% 20% 5%	2189
April	1st to 10th	Day	36% 9% 12% 18% 18% 8%	2160
	11th to 20th	Day	39% 8% 12% 19% 13% 8%	2134
	21st to end	Day	31% 9% 13% 21% 21% 5%	2160
May	1st to 10th	Day	30% 8% 14% 25% 17% 6%	2160
	11th to 20th	Day	33% 9% 13% 24% 18% 2	2128
	21st to end	Day	33% 12% 18% 24% 13% 1	2337
June	1st to 10th	Day	39% 13% 14% 23% 11%	2309
	11th to 20th	Day	36% 13% 18% 21% 11% 1	2340
	21st to end	Day	45% 16% 19% 14% 6%	2340
July	1st to 10th	Day	46% 17% 19% 16% 2	2276
	11th to 20th	Day	47% 16% 20% 14% 3	2271
	21st to end	Day	47% 14% 21% 14% 3 1	2346
August	1st to 10th	Day	37% 17% 24% 18% 5%	2136
	11th to 20th	Day	44% 16% 20% 16% 3 1	2125
	21st to end	Day	48% 13% 16% 14% 7% 2	2376
September	1st to 10th	Day	41% 14% 16% 17% 9% 4	2160
	11th to 20th	Day	45% 10% 14% 15% 12% 4	2160
	21st to end	Day	37% 7% 12% 21% 16% 8%	1934
October	1st to 10th	Day	28% 7% 11% 22% 22% 11%	1800
	11th to 20th	Day	29% 7% 8% 18% 24% 14%	1800
	21st to end	Day	32% 5% 7% 15% 25% 15%	1980
November	1st to 10th	Day	29% 7% 9% 20% 26% 9%	1858
	11th to 20th	Day	33% 4 8% 18% 26% 11%	1900
	21st to end	Day	37% 6% 9% 17% 21% 9%	1900
December	1st to 10th	Day	39% 7% 10% 21% 16% 7%	1900
	11th to 20th	Day	44% 7% 8% 15% 17% 10%	2336
	21st to end	Day	42% 8% 10% 14% 22% 4	3135
January	1st to 10th	Night	39% 7% 8% 15% 24% 8%	4108
	11th to 20th	Night	33% 5% 6% 18% 25% 12%	4120
	21st to end	Night	48% 4 6% 17% 17% 9%	4527
February	1st to 10th	Night	43% 5% 8% 16% 18% 10%	2275
	11th to 20th	Night	43% 5% 8% 16% 17% 12%	2099
	21st to end	Night	43% 7% 11% 14% 14% 11%	1722
March	1st to 10th	Night	36% 6% 13% 18% 18% 9%	1980
	11th to 20th	Night	39% 8% 15% 14% 17% 7%	1980
	21st to end	Night	29% 6% 14% 21% 22% 7%	2165
April	1st to 10th	Night	36% 7% 13% 18% 15% 10%	1800
	11th to 20th	Night	37% 6% 12% 19% 15% 11%	1775
	21st to end	Night	27% 8% 12% 23% 23% 7%	1800
May	1st to 10th	Night	29% 8% 14% 24% 17% 8%	1800
	11th to 20th	Night	27% 10% 14% 24% 22% 2	1770
	21st to end	Night	25% 8% 19% 30% 16% 2	1939
June	1st to 10th	Night	29% 10% 22% 25% 13% 1	1645
	11th to 20th	Night	27% 11% 21% 29% 12% 1	1620
	21st to end	Night	36% 12% 23% 22% 6%	1620
July	1st to 10th	Night	31% 15% 31% 19% 4	1575
	11th to 20th	Night	29% 15% 32% 18% 5%	1566
	21st to end	Night	28% 14% 33% 20% 5%	1728
August	1st to 10th	Night	20% 15% 34% 25% 6%	1778
	11th to 20th	Night	29% 17% 29% 21% 3 1	1776
	21st to end	Night	35% 13% 22% 20% 7% 3	1980
September	1st to 10th	Night	31% 13% 23% 19% 10% 4	1800
	11th to 20th	Night	36% 11% 18% 17% 13% 4	1800
	21st to end	Night	29% 8% 16% 24% 15% 9%	2002
October	1st to 10th	Night	25% 5% 13% 22% 20% 14%	2160
	11th to 20th	Night	24% 7% 10% 21% 23% 15%	2160
	21st to end	Night	28% 5% 8% 17% 24% 19%	2376
November	1st to 10th	Night	29% 6% 10% 20% 25% 11%	2220
	11th to 20th	Night	30% 4 8% 17% 27% 13%	2280
	21st to end	Night	36% 6% 8% 19% 21% 10%	2280
December	1st to 10th	Night	39% 5% 9% 21% 18% 7%	2280
	11th to 20th	Night	40% 7% 9% 14% 18% 13%	2841
	21st to end	Night	46% 6% 10% 12% 19% 8%	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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	20% 14% 35% 22% 7% 2	270
	11th to 20th	Day	15% 14% 35% 27% 7% 1	270
	21st to end	Day	23% 15% 37% 21% 5%	297
February	1st to 10th	Day	22% 11% 32% 26% 10%	267
	11th to 20th	Day	27% 12% 28% 22% 10%	240
	21st to end	Day	13% 16% 51% 16% 4 2	198
March	1st to 10th	Day	15% 13% 38% 26% 8%	240
	11th to 20th	Day	16% 13% 40% 25% 6%	240
	21st to end	Day	12% 16% 36% 25% 10% 1	275
April	1st to 10th	Day	14% 9% 31% 33% 11% 2	420
	11th to 20th	Day	21% 8% 29% 23% 17% 2	412
	21st to end	Day	10% 7% 29% 34% 18% 2	420
May	1st to 10th	Day	10% 5% 24% 37% 21% 4	423
	11th to 20th	Day	9% 2 18% 35% 28% 8%	447
	21st to end	Day	7% 3 10% 33% 33% 14%	485
June	1st to 10th	Day	9% 2 11% 28% 31% 20%	599
	11th to 20th	Day	6% 2 11% 32% 33% 16%	630
	21st to end	Day	10% 3 9% 23% 31% 24%	630
July	1st to 10th	Day	8% 2 3 22% 35% 30%	621
	11th to 20th	Day	8% 1 4 17% 37% 33%	618
	21st to end	Day	9% 1 6% 16% 39% 29%	622
August	1st to 10th	Day	5% 1 3 12% 35% 45%	446
	11th to 20th	Day	8% 2 10% 35% 44%	439
	21st to end	Day	12% 1 5% 15% 35% 32%	495
September	1st to 10th	Day	9% 3 4 17% 35% 31%	450
	11th to 20th	Day	13% 2 6% 18% 40% 21%	450
	21st to end	Day	13% 1 7% 21% 37% 22%	372
October	1st to 10th	Day	7% 1 14% 34% 35% 10%	270
	11th to 20th	Day	8% 3 14% 36% 24% 14%	270
	21st to end	Day	19% 8% 19% 29% 20% 6%	297
November	1st to 10th	Day	12% 4 18% 35% 27% 4	270
	11th to 20th	Day	16% 8% 26% 28% 19% 2	270
	21st to end	Day	13% 12% 31% 26% 13% 4	270
December	1st to 10th	Day	19% 6% 28% 25% 16% 6%	270
	11th to 20th	Day	19% 11% 34% 30% 6%	270
	21st to end	Day	23% 9% 33% 23% 11% 1	297
January	1st to 10th	Night	17% 9% 32% 32% 9% 1	950
	11th to 20th	Night	17% 10% 31% 33% 10%	950
	21st to end	Night	20% 9% 33% 30% 8%	1040
February	1st to 10th	Night	17% 9% 33% 35% 6%	759
	11th to 20th	Night	20% 11% 26% 33% 9%	703
	21st to end	Night	20% 11% 35% 30% 4	538
March	1st to 10th	Night	14% 9% 31% 36% 10%	540
	11th to 20th	Night	13% 5% 30% 38% 14%	540
	21st to end	Night	12% 8% 28% 37% 15%	594
April	1st to 10th	Night	14% 7% 32% 32% 13% 1	540
	11th to 20th	Night	12% 8% 33% 29% 17% 1	533
	21st to end	Night	7% 4 29% 41% 18% 1	540
May	1st to 10th	Night	11% 3 19% 47% 18% 2	540
	11th to 20th	Night	6% 3 17% 45% 26% 4	531
	21st to end	Night	6% 2 8% 38% 39% 8%	584
June	1st to 10th	Night	6% 2 5% 32% 44% 10%	540
	11th to 20th	Night	3 1 4 27% 52% 13%	540
	21st to end	Night	9% 1 4 22% 47% 17%	540
July	1st to 10th	Night	5% 2 4 11% 54% 23%	525
	11th to 20th	Night	6% 1 3 8% 53% 31%	522
	21st to end	Night	5% 1 4 14% 50% 26%	591
August	1st to 10th	Night	2 2 10% 50% 35%	537
	11th to 20th	Night	5% 2 9% 51% 33%	534
	21st to end	Night	8% 1 3 16% 48% 23%	594
September	1st to 10th	Night	5% 2 4 17% 50% 22%	540
	11th to 20th	Night	11% 1 5% 22% 49% 12%	540
	21st to end	Night	7% 1 7% 27% 50% 8%	670
October	1st to 10th	Night	6% 2 11% 35% 40% 6%	720
	11th to 20th	Night	9% 3 16% 35% 32% 4	720
	21st to end	Night	11% 5% 17% 38% 24% 4	792
November	1st to 10th	Night	10% 3 15% 42% 27% 3	740
	11th to 20th	Night	12% 5% 21% 41% 19% 1	760
	21st to end	Night	15% 6% 26% 38% 15% 1	760
December	1st to 10th	Night	17% 7% 24% 32% 19% 1	760
	11th to 20th	Night	16% 8% 26% 38% 11% 1	788
	21st to end	Night	22% 9% 27% 30% 11%	1045

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