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 2026-07-16.

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	10% 6% 3 7% 5% 5% 5% 5% 7% 9% 38%	137052
	Night	11% 6% 2 6% 4 4 4 4 6% 8% 44%	135774
Transparency	Day	38% 9% 14% 18% 15% 6%	140663
	Night	35% 8% 14% 18% 17% 8%	140243
Seeing	Day	12% 6% 19% 25% 24% 14%	17042
	Night	12% 5% 19% 31% 26% 7%	26712

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	16% 7% 4 7% 4 4 4 4 6% 7% 38%	5289
	11th to 20th	Day	12% 7% 2 6% 4 4 4 3 5% 6% 47%	5310
	21st to end	Day	20% 9% 3 8% 4 4 4 3 4 6% 34%	5826
February	1st to 10th	Day	15% 9% 2 8% 4 4 4 4 5% 6% 38%	2100
	11th to 20th	Day	16% 8% 2 7% 4 4 4 4 6% 7% 40%	2048
	21st to end	Day	16% 9% 3 5% 4 3 4 4 6% 7% 39%	1809
March	1st to 10th	Day	19% 8% 3 7% 5% 4 4 3 5% 7% 34%	5046
	11th to 20th	Day	10% 5% 2 6% 5% 4 4 5% 7% 7% 44%	5090
	21st to end	Day	12% 7% 3 6% 4 4 4 4 5% 7% 44%	5622
April	1st to 10th	Day	11% 7% 2 6% 5% 5% 5% 4 7% 8% 41%	2520
	11th to 20th	Day	13% 6% 2 5% 5% 5% 4 4 7% 8% 41%	2494
	21st to end	Day	8% 5% 2 5% 5% 5% 6% 5% 7% 9% 45%	2520
May	1st to 10th	Day	17% 7% 3 8% 5% 4 6% 4 7% 9% 30%	7021
	11th to 20th	Day	7% 5% 2 6% 5% 5% 6% 5% 7% 10% 44%	7031
	21st to end	Day	7% 5% 2 6% 5% 6% 7% 6% 10% 13% 34%	7736
June	1st to 10th	Day	7% 4 2 8% 7% 7% 6% 6% 9% 11% 33%	2695
	11th to 20th	Day	5% 4 3 7% 6% 8% 7% 6% 9% 11% 33%	2730
	21st to end	Day	7% 6% 3 8% 7% 8% 9% 7% 9% 10% 27%	2730
July	1st to 10th	Day	5% 5% 3 9% 7% 8% 8% 7% 9% 12% 26%	6030
	11th to 20th	Day	5% 5% 2 8% 7% 7% 8% 6% 10% 13% 28%	5966
	21st to end	Day	6% 7% 3 10% 7% 8% 7% 7% 9% 11% 25%	6252
August	1st to 10th	Day	3 3 2 5% 4 5% 5% 5% 8% 11% 49%	3905
	11th to 20th	Day	5% 3 2 6% 5% 6% 7% 6% 10% 15% 35%	3849
	21st to end	Day	9% 8% 4 10% 7% 7% 6% 5% 6% 7% 30%	4312
September	1st to 10th	Day	11% 5% 3 7% 6% 6% 6% 5% 8% 8% 33%	2400
	11th to 20th	Day	11% 7% 3 8% 5% 6% 6% 4 7% 8% 35%	2400
	21st to end	Day	9% 6% 2 6% 5% 4 4 3 6% 7% 47%	2146
October	1st to 10th	Day	5% 4 2 6% 5% 3 4 5% 6% 6% 55%	2000
	11th to 20th	Day	7% 5% 2 5% 3 3 4 3 5% 8% 54%	2000
	21st to end	Day	10% 5% 2 4 4 4 3 3 5% 6% 53%	2200
November	1st to 10th	Day	7% 5% 2 5% 3 4 4 4 7% 7% 51%	2058
	11th to 20th	Day	10% 5% 2 5% 3 3 4 3 5% 5% 55%	2100
	21st to end	Day	12% 5% 2 6% 4 4 4 4 5% 7% 46%	2100
December	1st to 10th	Day	17% 9% 3 8% 5% 4 3 3 4 5% 39%	3360
	11th to 20th	Day	9% 6% 2 6% 5% 5% 5% 4 5% 7% 46%	3770
	21st to end	Day	13% 7% 3 6% 4 4 4 3 4 6% 46%	4587
January	1st to 10th	Night	18% 6% 3 6% 4 3 3 3 4 5% 44%	7634
	11th to 20th	Night	14% 7% 2 6% 4 3 4 3 5% 6% 47%	7680
	21st to end	Night	21% 9% 3 8% 4 4 4 3 4 6% 34%	8369
February	1st to 10th	Night	14% 8% 3 6% 5% 4 5% 3 4 6% 42%	2520
	11th to 20th	Night	17% 8% 3 7% 4 3 3 3 5% 5% 40%	2458
	21st to end	Night	16% 9% 2 6% 4 3 4 4 5% 5% 42%	2013
March	1st to 10th	Night	18% 10% 3 7% 4 3 4 3 5% 6% 38%	5029
	11th to 20th	Night	13% 7% 2 6% 4 3 4 3 5% 5% 47%	5090
	21st to end	Night	15% 8% 3 6% 4 4 4 3 5% 6% 43%	5547
April	1st to 10th	Night	13% 6% 2 5% 4 5% 4 3 5% 8% 45%	2100
	11th to 20th	Night	11% 6% 2 6% 4 4 3 3 4 6% 50%	2075
	21st to end	Night	7% 5% 2 5% 4 4 5% 4 7% 8% 50%	2100
May	1st to 10th	Night	18% 10% 3 8% 5% 4 4 3 5% 7% 33%	5832
	11th to 20th	Night	11% 6% 2 7% 4 4 5% 4 6% 9% 42%	5829
	21st to end	Night	8% 6% 2 7% 4 5% 5% 4 7% 11% 40%	6415
June	1st to 10th	Night	5% 4 2 6% 3 5% 5% 5% 8% 11% 46%	1918
	11th to 20th	Night	4 4 2 5% 5% 5% 6% 5% 8% 11% 46%	1890
	21st to end	Night	7% 5% 2 6% 6% 4 6% 5% 9% 12% 40%	1890
July	1st to 10th	Night	3 5% 2 7% 5% 5% 6% 5% 10% 13% 40%	4168
	11th to 20th	Night	3 3 2 5% 4 5% 5% 6% 9% 12% 46%	4122
	21st to end	Night	3 5% 2 7% 6% 6% 6% 5% 9% 13% 39%	4596
August	1st to 10th	Night	1 2 1 3 3 4 4 4 6% 12% 60%	3244
	11th to 20th	Night	2 2 1 4 3 4 5% 5% 8% 16% 50%	3200
	21st to end	Night	5% 5% 3 8% 5% 6% 6% 5% 8% 8% 41%	3586
September	1st to 10th	Night	7% 6% 2 6% 4 5% 5% 4 8% 11% 42%	2000
	11th to 20th	Night	9% 6% 3 7% 4 5% 5% 4 7% 9% 41%	2000
	21st to end	Night	5% 5% 2 5% 4 3 3 4 6% 7% 54%	2226
October	1st to 10th	Night	5% 4 2 5% 4 3 3 3 5% 6% 59%	2400
	11th to 20th	Night	6% 4 1 4 3 3 4 2 5% 7% 61%	2400
	21st to end	Night	9% 4 2 4 3 3 3 3 4 6% 58%	2640
November	1st to 10th	Night	8% 6% 2 6% 4 3 4 3 5% 6% 54%	2460
	11th to 20th	Night	10% 4 2 5% 3 2 3 3 4 6% 57%	2520
	21st to end	Night	12% 6% 2 6% 3 4 3 4 6% 7% 47%	2520
December	1st to 10th	Night	16% 8% 3 8% 5% 4 3 3 4 6% 40%	4040
	11th to 20th	Night	8% 7% 2 6% 5% 4 4 3 6% 6% 49%	4630
	21st to end	Night	14% 10% 3 7% 4 4 3 2 4 5% 45%	6633

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% 9% 19% 18% 6%	5290
	11th to 20th	Day	37% 4 6% 18% 25% 10%	5310
	21st to end	Day	50% 5% 7% 12% 14% 11%	5826
February	1st to 10th	Day	45% 6% 9% 14% 19% 8%	2100
	11th to 20th	Day	43% 7% 8% 17% 16% 10%	2058
	21st to end	Day	42% 8% 12% 14% 17% 7%	1809
March	1st to 10th	Day	47% 7% 10% 14% 13% 9%	5046
	11th to 20th	Day	35% 9% 12% 13% 17% 15%	5090
	21st to end	Day	37% 7% 12% 19% 19% 7%	5624
April	1st to 10th	Day	37% 8% 12% 18% 17% 8%	2520
	11th to 20th	Day	37% 7% 12% 21% 14% 8%	2494
	21st to end	Day	31% 9% 14% 21% 20% 5%	2520
May	1st to 10th	Day	45% 10% 14% 19% 10% 2	7056
	11th to 20th	Day	31% 9% 17% 23% 17% 2	7035
	21st to end	Day	33% 13% 22% 24% 7%	7749
June	1st to 10th	Day	38% 13% 15% 22% 12%	2695
	11th to 20th	Day	37% 13% 18% 21% 11% 1	2730
	21st to end	Day	43% 15% 20% 16% 6%	2730
July	1st to 10th	Day	42% 14% 28% 15% 1	5966
	11th to 20th	Day	41% 16% 31% 10% 1	5897
	21st to end	Day	47% 13% 20% 18% 2	6072
August	1st to 10th	Day	23% 12% 15% 30% 19%	3893
	11th to 20th	Day	32% 14% 27% 23% 4	3885
	21st to end	Day	50% 10% 12% 14% 12% 2	4311
September	1st to 10th	Day	41% 13% 16% 17% 9% 3	2400
	11th to 20th	Day	43% 10% 13% 16% 13% 4	2400
	21st to end	Day	35% 7% 12% 22% 16% 9%	2146
October	1st to 10th	Day	25% 4 7% 13% 23% 27%	3260
	11th to 20th	Day	18% 4 5% 22% 29% 22%	3240
	21st to end	Day	25% 5% 5% 12% 41% 13%	3538
November	1st to 10th	Day	29% 6% 10% 20% 25% 10%	2058
	11th to 20th	Day	31% 4 7% 18% 26% 13%	2100
	21st to end	Day	36% 6% 10% 18% 21% 9%	2100
December	1st to 10th	Day	48% 5% 7% 15% 20% 5%	3360
	11th to 20th	Day	35% 6% 10% 18% 20% 11%	3768
	21st to end	Day	37% 7% 9% 17% 23% 7%	4587
January	1st to 10th	Night	40% 6% 10% 17% 20% 7%	7635
	11th to 20th	Night	38% 4 5% 17% 24% 12%	7680
	21st to end	Night	51% 4 7% 12% 16% 9%	8369
February	1st to 10th	Night	43% 5% 7% 16% 19% 10%	2520
	11th to 20th	Night	46% 5% 8% 15% 16% 11%	2459
	21st to end	Night	42% 7% 11% 14% 15% 11%	2013
March	1st to 10th	Night	46% 6% 9% 14% 15% 11%	5029
	11th to 20th	Night	37% 7% 10% 14% 18% 15%	5090
	21st to end	Night	40% 7% 10% 19% 18% 7%	5547
April	1st to 10th	Night	37% 7% 13% 18% 14% 11%	2100
	11th to 20th	Night	35% 6% 11% 21% 16% 11%	2075
	21st to end	Night	29% 8% 14% 22% 21% 6%	2100
May	1st to 10th	Night	47% 10% 13% 16% 11% 3	5862
	11th to 20th	Night	35% 9% 15% 24% 17% 1	5830
	21st to end	Night	33% 12% 22% 24% 8% 1	6427
June	1st to 10th	Night	28% 11% 23% 24% 14% 1	1918
	11th to 20th	Night	29% 10% 21% 27% 12% 1	1890
	21st to end	Night	33% 11% 25% 24% 6%	1890
July	1st to 10th	Night	30% 14% 37% 17% 2	4125
	11th to 20th	Night	27% 15% 44% 12% 2	4071
	21st to end	Night	33% 15% 27% 23% 3	4464
August	1st to 10th	Night	16% 10% 22% 32% 19%	3232
	11th to 20th	Night	20% 12% 37% 28% 2	3230
	21st to end	Night	38% 11% 18% 20% 12% 2	3586
September	1st to 10th	Night	32% 13% 23% 18% 10% 4	2000
	11th to 20th	Night	35% 11% 18% 18% 14% 4	2000
	21st to end	Night	27% 8% 16% 24% 15% 10%	2226
October	1st to 10th	Night	27% 4 9% 14% 19% 27%	3920
	11th to 20th	Night	15% 5% 6% 20% 32% 22%	3899
	21st to end	Night	19% 4 7% 12% 39% 20%	4252
November	1st to 10th	Night	30% 6% 9% 19% 25% 11%	2460
	11th to 20th	Night	29% 4 8% 18% 27% 14%	2520
	21st to end	Night	35% 6% 9% 19% 21% 11%	2520
December	1st to 10th	Night	46% 4 7% 18% 20% 6%	4040
	11th to 20th	Night	33% 6% 12% 19% 18% 11%	4631
	21st to end	Night	41% 5% 9% 12% 23% 9%	6633

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	19% 15% 36% 20% 7% 2	330
	11th to 20th	Day	15% 14% 38% 25% 7% 1	330
	21st to end	Day	23% 17% 33% 23% 4	363
February	1st to 10th	Day	19% 10% 33% 28% 11%	330
	11th to 20th	Day	23% 14% 32% 21% 9% 1	330
	21st to end	Day	13% 15% 50% 16% 4 1	273
March	1st to 10th	Day	16% 14% 36% 25% 8% 1	330
	11th to 20th	Day	14% 17% 38% 23% 7% 1	330
	21st to end	Day	12% 14% 33% 26% 12% 3	377
April	1st to 10th	Day	14% 12% 30% 32% 10% 1	540
	11th to 20th	Day	17% 10% 30% 25% 16% 1	532
	21st to end	Day	9% 7% 31% 33% 16% 3	540
May	1st to 10th	Day	13% 8% 24% 35% 17% 3	543
	11th to 20th	Day	9% 4 23% 33% 24% 7%	567
	21st to end	Day	6% 3 14% 35% 30% 12%	617
June	1st to 10th	Day	9% 3 12% 30% 30% 17%	745
	11th to 20th	Day	7% 2 10% 33% 33% 15%	780
	21st to end	Day	9% 3 8% 24% 32% 25%	780
July	1st to 10th	Day	7% 2 5% 22% 36% 29%	771
	11th to 20th	Day	9% 2 4 17% 37% 32%	744
	21st to end	Day	9% 1 5% 17% 39% 29%	724
August	1st to 10th	Day	5% 1 3 12% 37% 42%	526
	11th to 20th	Day	7% 2 11% 33% 47%	519
	21st to end	Day	11% 2 4 16% 36% 31%	583
September	1st to 10th	Day	11% 3 5% 20% 34% 27%	530
	11th to 20th	Day	12% 2 7% 17% 40% 21%	530
	21st to end	Day	11% 1 9% 23% 36% 20%	442
October	1st to 10th	Day	7% 1 15% 34% 34% 9%	330
	11th to 20th	Day	7% 3 14% 38% 25% 13%	330
	21st to end	Day	16% 8% 19% 30% 20% 7%	363
November	1st to 10th	Day	11% 5% 21% 33% 25% 5%	330
	11th to 20th	Day	14% 7% 26% 30% 19% 4	330
	21st to end	Day	12% 12% 32% 27% 13% 4	330
December	1st to 10th	Day	22% 6% 31% 22% 14% 5%	330
	11th to 20th	Day	16% 9% 34% 30% 10%	330
	21st to end	Day	20% 9% 32% 23% 13% 2	363
January	1st to 10th	Night	18% 9% 32% 32% 8%	1050
	11th to 20th	Night	16% 11% 31% 32% 9%	1050
	21st to end	Night	20% 10% 33% 30% 7%	1148
February	1st to 10th	Night	16% 9% 33% 36% 7%	840
	11th to 20th	Night	22% 12% 26% 31% 8%	823
	21st to end	Night	20% 11% 35% 29% 5%	629
March	1st to 10th	Night	15% 10% 30% 35% 10%	630
	11th to 20th	Night	12% 6% 31% 37% 13%	630
	21st to end	Night	12% 8% 27% 36% 16%	693
April	1st to 10th	Night	15% 8% 31% 32% 13% 1	630
	11th to 20th	Night	11% 8% 32% 33% 16% 1	623
	21st to end	Night	8% 5% 28% 41% 17% 1	630
May	1st to 10th	Night	13% 4 20% 45% 17% 2	630
	11th to 20th	Night	7% 4 19% 43% 24% 3	621
	21st to end	Night	6% 3 10% 38% 36% 7%	683
June	1st to 10th	Night	6% 2 7% 34% 42% 9%	630
	11th to 20th	Night	5% 1 5% 27% 51% 12%	630
	21st to end	Night	8% 2 4 21% 48% 17%	630
July	1st to 10th	Night	5% 2 4 12% 53% 24%	615
	11th to 20th	Night	5% 1 2 8% 53% 31%	597
	21st to end	Night	5% 1 4 14% 50% 26%	657
August	1st to 10th	Night	2 2 11% 50% 35%	597
	11th to 20th	Night	4 2 9% 51% 33%	594
	21st to end	Night	7% 1 4 16% 49% 23%	660
September	1st to 10th	Night	7% 3 4 18% 49% 20%	600
	11th to 20th	Night	11% 2 5% 22% 49% 11%	600
	21st to end	Night	7% 2 8% 28% 49% 7%	745
October	1st to 10th	Night	7% 2 12% 35% 38% 6%	800
	11th to 20th	Night	8% 3 16% 38% 31% 4	800
	21st to end	Night	11% 5% 17% 39% 24% 4	880
November	1st to 10th	Night	10% 4 16% 42% 26% 3	820
	11th to 20th	Night	12% 5% 21% 41% 20% 1	840
	21st to end	Night	14% 6% 26% 38% 15% 1	840
December	1st to 10th	Night	18% 8% 24% 32% 17% 1	840
	11th to 20th	Night	15% 8% 25% 39% 12% 1	872
	21st to end	Night	20% 9% 27% 30% 13% 1	1155

Page generated at 2026-07-13 02:14:50. Version ac07

Copyright © 2026 Attilla Danko.