Jackson (MS)
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Jackson (MS) clear sky chart from 2005-11-06 to 2025-07-21.

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% 2 6% 5% 5% 5% 4 6% 8% 42%	119302
	Night	12% 6% 2 6% 4 4 4 3 5% 7% 46%	119898
Transparency	Day	39% 5% 11% 20% 19% 7%	123009
	Night	37% 4 10% 19% 21% 9%	124334
Seeing	Day	13% 9% 21% 25% 22% 10%	15957
	Night	14% 7% 24% 30% 21% 4	25657

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	14% 10% 4 9% 3 3 3 3 5% 5% 42%	4077
	11th to 20th	Day	12% 6% 2 5% 3 3 4 3 6% 6% 49%	4080
	21st to end	Day	21% 11% 3 6% 3 3 3 2 3 4 40%	4634
February	1st to 10th	Day	15% 11% 3 7% 5% 3 4 3 5% 5% 40%	2000
	11th to 20th	Day	21% 9% 3 5% 4 3 4 2 5% 5% 39%	1948
	21st to end	Day	17% 8% 3 7% 6% 4 3 4 4 5% 39%	1650
March	1st to 10th	Day	18% 9% 3 9% 5% 5% 5% 4 5% 7% 31%	4655
	11th to 20th	Day	13% 6% 2 5% 4 5% 5% 4 6% 7% 44%	4980
	21st to end	Day	13% 9% 3 8% 6% 4 4 4 5% 5% 39%	5737
April	1st to 10th	Day	11% 5% 3 6% 5% 4 5% 4 6% 7% 44%	2400
	11th to 20th	Day	14% 7% 2 6% 4 4 3 3 5% 7% 44%	2374
	21st to end	Day	8% 5% 2 6% 5% 5% 5% 4 6% 9% 46%	2400
May	1st to 10th	Day	14% 7% 2 6% 5% 5% 5% 4 7% 9% 37%	5405
	11th to 20th	Day	10% 6% 3 7% 6% 5% 5% 4 7% 9% 38%	5404
	21st to end	Day	8% 4 2 6% 5% 4 5% 4 8% 11% 43%	6206
June	1st to 10th	Day	9% 5% 1 6% 5% 7% 6% 5% 8% 11% 37%	2752
	11th to 20th	Day	5% 5% 2 6% 6% 6% 7% 5% 8% 10% 42%	2800
	21st to end	Day	5% 4 2 6% 6% 7% 7% 5% 8% 10% 39%	2772
July	1st to 10th	Day	4 5% 3 8% 7% 7% 9% 7% 9% 11% 29%	4250
	11th to 20th	Day	7% 4 3 7% 5% 7% 8% 7% 10% 12% 31%	4250
	21st to end	Day	11% 8% 4 10% 7% 6% 7% 5% 8% 9% 26%	4290
August	1st to 10th	Day	3 3 1 4 3 4 4 4 6% 7% 63%	3785
	11th to 20th	Day	4 3 2 5% 5% 5% 5% 5% 7% 11% 46%	3729
	21st to end	Day	8% 4 2 6% 5% 6% 5% 4 6% 8% 45%	4180
September	1st to 10th	Day	8% 5% 2 7% 7% 5% 7% 5% 6% 8% 41%	2280
	11th to 20th	Day	12% 6% 2 7% 4 5% 5% 4 5% 7% 43%	2228
	21st to end	Day	9% 4 2 4 3 3 4 4 5% 8% 53%	2090
October	1st to 10th	Day	6% 4 1 5% 4 3 4 3 4 6% 59%	1979
	11th to 20th	Day	8% 5% 2 5% 4 3 3 3 5% 6% 56%	1900
	21st to end	Day	12% 5% 2 4 3 3 3 2 3 5% 57%	2090
November	1st to 10th	Day	10% 5% 2 5% 4 4 4 3 5% 6% 53%	1956
	11th to 20th	Day	11% 7% 2 5% 4 3 3 4 4 6% 52%	1800
	21st to end	Day	14% 7% 2 5% 4 4 3 3 4 6% 47%	1800
December	1st to 10th	Day	17% 8% 2 6% 4 3 3 3 5% 7% 43%	2930
	11th to 20th	Day	13% 9% 3 9% 5% 5% 4 2 4 6% 41%	3302
	21st to end	Day	15% 7% 2 6% 3 3 3 3 5% 6% 47%	4189
January	1st to 10th	Night	18% 8% 3 6% 3 2 3 2 3 4 47%	5888
	11th to 20th	Night	14% 7% 3 6% 3 3 3 3 4 5% 48%	5900
	21st to end	Night	24% 9% 2 5% 3 3 3 2 3 4 40%	6334
February	1st to 10th	Night	16% 9% 3 6% 4 3 4 3 4 6% 43%	2400
	11th to 20th	Night	19% 8% 2 5% 3 3 3 3 4 5% 44%	2338
	21st to end	Night	19% 8% 3 6% 4 3 3 3 4 5% 42%	1980
March	1st to 10th	Night	17% 8% 3 6% 4 4 4 3 5% 6% 39%	5239
	11th to 20th	Night	10% 6% 2 5% 4 4 4 4 5% 7% 49%	4980
	21st to end	Night	16% 7% 2 6% 4 4 4 4 5% 6% 43%	5178
April	1st to 10th	Night	12% 5% 2 5% 5% 4 4 4 6% 5% 47%	2000
	11th to 20th	Night	12% 5% 2 4 4 4 5% 4 5% 6% 49%	1975
	21st to end	Night	8% 5% 2 6% 4 4 4 4 6% 7% 52%	2000
May	1st to 10th	Night	13% 6% 2 6% 4 5% 5% 4 6% 9% 40%	4490
	11th to 20th	Night	15% 6% 2 7% 5% 4 5% 4 7% 8% 38%	4489
	21st to end	Night	7% 5% 2 6% 5% 5% 6% 5% 8% 10% 41%	4630
June	1st to 10th	Night	6% 6% 2 5% 6% 5% 5% 4 7% 10% 44%	1642
	11th to 20th	Night	3 4 2 3 5% 4 5% 5% 8% 12% 49%	1600
	21st to end	Night	4 4 2 6% 5% 4 6% 5% 8% 12% 45%	1619
July	1st to 10th	Night	5% 5% 3 8% 6% 5% 5% 6% 8% 13% 38%	2940
	11th to 20th	Night	5% 5% 3 6% 5% 5% 7% 6% 11% 14% 33%	2940
	21st to end	Night	8% 8% 4 9% 6% 5% 5% 4 7% 9% 34%	3268
August	1st to 10th	Night	2 2 1 3 3 3 4 4 6% 11% 62%	3144
	11th to 20th	Night	3 3 1 5% 4 4 5% 5% 8% 13% 48%	3100
	21st to end	Night	6% 4 2 6% 4 6% 5% 4 6% 8% 47%	3476
September	1st to 10th	Night	8% 5% 2 6% 4 5% 5% 5% 6% 9% 46%	1900
	11th to 20th	Night	8% 7% 2 6% 4 4 5% 4 6% 7% 46%	1931
	21st to end	Night	8% 4 2 4 3 4 4 4 4 6% 56%	2090
October	1st to 10th	Night	6% 3 2 4 3 3 4 3 4 6% 62%	2195
	11th to 20th	Night	10% 5% 1 4 4 3 3 3 5% 6% 56%	2280
	21st to end	Night	13% 6% 1 4 3 3 3 2 4 4 58%	2508
November	1st to 10th	Night	11% 5% 2 5% 2 3 3 3 4 6% 57%	2340
	11th to 20th	Night	13% 5% 1 5% 3 3 3 3 4 6% 55%	2599
	21st to end	Night	13% 6% 2 5% 3 4 4 3 5% 6% 49%	2600
December	1st to 10th	Night	20% 6% 2 5% 3 3 3 3 4 5% 45%	4250
	11th to 20th	Night	14% 9% 2 6% 5% 5% 3 2 4 5% 45%	4886
	21st to end	Night	17% 10% 2 5% 3 3 2 2 4 5% 46%	6769

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	45% 3 4 22% 22% 4	4078
	11th to 20th	Day	35% 3 6% 21% 28% 7%	4080
	21st to end	Day	50% 2 6% 12% 19% 12%	4634
February	1st to 10th	Day	48% 3 6% 16% 18% 9%	2000
	11th to 20th	Day	48% 3 5% 17% 19% 8%	1958
	21st to end	Day	48% 4 6% 14% 19% 9%	1650
March	1st to 10th	Day	54% 3 5% 14% 17% 7%	4655
	11th to 20th	Day	40% 3 6% 15% 19% 15%	4980
	21st to end	Day	47% 3 8% 18% 17% 7%	5739
April	1st to 10th	Day	39% 4 9% 22% 17% 8%	2400
	11th to 20th	Day	41% 3 7% 17% 24% 7%	2374
	21st to end	Day	35% 5% 9% 25% 23% 3	2400
May	1st to 10th	Day	43% 6% 13% 24% 13% 2	5440
	11th to 20th	Day	43% 4 17% 19% 16% 1	5408
	21st to end	Day	34% 5% 18% 27% 16% 1	6220
June	1st to 10th	Day	39% 7% 14% 24% 14% 1	2752
	11th to 20th	Day	36% 8% 17% 23% 14% 3	2800
	21st to end	Day	37% 9% 17% 23% 12% 2	2772
July	1st to 10th	Day	45% 7% 20% 19% 7% 1	4186
	11th to 20th	Day	41% 8% 29% 18% 3 1	4181
	21st to end	Day	53% 7% 12% 21% 6%	4154
August	1st to 10th	Day	20% 6% 12% 29% 30% 3	3773
	11th to 20th	Day	31% 6% 18% 30% 14% 2	3765
	21st to end	Day	37% 6% 14% 21% 18% 4	4179
September	1st to 10th	Day	39% 8% 14% 17% 16% 6%	2280
	11th to 20th	Day	41% 5% 10% 17% 20% 7%	2228
	21st to end	Day	29% 4 11% 24% 21% 10%	2090
October	1st to 10th	Day	19% 4 5% 15% 26% 32%	3291
	11th to 20th	Day	18% 3 3 14% 32% 30%	3140
	21st to end	Day	23% 2 4 17% 38% 17%	3428
November	1st to 10th	Day	33% 4 7% 16% 29% 11%	1956
	11th to 20th	Day	35% 3 5% 15% 28% 14%	1800
	21st to end	Day	39% 3 7% 18% 24% 10%	1800
December	1st to 10th	Day	43% 3 7% 18% 24% 5%	2930
	11th to 20th	Day	47% 3 7% 16% 19% 8%	3299
	21st to end	Day	39% 3 5% 24% 27% 2	4189
January	1st to 10th	Night	42% 3 4 21% 24% 6%	5888
	11th to 20th	Night	40% 3 4 16% 26% 11%	5900
	21st to end	Night	50% 2 4 14% 21% 9%	6334
February	1st to 10th	Night	44% 3 6% 16% 22% 9%	2400
	11th to 20th	Night	44% 3 6% 17% 20% 10%	2339
	21st to end	Night	46% 5% 7% 14% 16% 12%	1980
March	1st to 10th	Night	46% 4 6% 14% 20% 10%	5239
	11th to 20th	Night	35% 4 7% 18% 20% 17%	4980
	21st to end	Night	43% 3 10% 18% 19% 7%	5178
April	1st to 10th	Night	37% 5% 11% 18% 19% 10%	2000
	11th to 20th	Night	36% 3 9% 20% 22% 9%	1975
	21st to end	Night	31% 4 9% 25% 26% 5%	2000
May	1st to 10th	Night	40% 5% 13% 23% 16% 3	4520
	11th to 20th	Night	44% 4 15% 23% 13% 1	4490
	21st to end	Night	36% 6% 17% 25% 15% 2	4638
June	1st to 10th	Night	35% 5% 17% 24% 16% 2	1642
	11th to 20th	Night	27% 8% 19% 27% 15% 4	1600
	21st to end	Night	30% 7% 21% 24% 15% 3	1619
July	1st to 10th	Night	37% 10% 23% 21% 7% 2	2895
	11th to 20th	Night	36% 10% 30% 19% 4 1	2886
	21st to end	Night	46% 7% 19% 21% 7% 1	3164
August	1st to 10th	Night	17% 7% 16% 32% 26% 2	3132
	11th to 20th	Night	26% 7% 21% 32% 11% 2	3130
	21st to end	Night	35% 7% 14% 21% 19% 5%	3476
September	1st to 10th	Night	33% 8% 14% 21% 17% 7%	1900
	11th to 20th	Night	36% 6% 13% 16% 20% 9%	1931
	21st to end	Night	28% 5% 10% 24% 21% 11%	2090
October	1st to 10th	Night	17% 4 6% 16% 24% 34%	3663
	11th to 20th	Night	20% 2 4 16% 25% 33%	3779
	21st to end	Night	22% 2 5% 14% 36% 22%	4120
November	1st to 10th	Night	31% 3 7% 18% 29% 13%	2340
	11th to 20th	Night	32% 3 7% 15% 28% 16%	2599
	21st to end	Night	37% 3 6% 20% 21% 13%	2600
December	1st to 10th	Night	44% 2 6% 18% 25% 5%	4250
	11th to 20th	Night	45% 2 7% 16% 24% 6%	4888
	21st to end	Night	42% 3 5% 20% 27% 3	6769

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	23% 24% 36% 14% 2 1	300
	11th to 20th	Day	25% 19% 35% 15% 5% 1	300
	21st to end	Day	25% 22% 35% 15% 3	330
February	1st to 10th	Day	18% 23% 36% 16% 6% 1	300
	11th to 20th	Day	33% 17% 34% 13% 2 1	300
	21st to end	Day	22% 27% 36% 12% 3	249
March	1st to 10th	Day	24% 17% 40% 15% 4	300
	11th to 20th	Day	23% 22% 34% 16% 4	300
	21st to end	Day	19% 17% 34% 24% 5%	450
April	1st to 10th	Day	16% 18% 34% 23% 9% 1	500
	11th to 20th	Day	21% 15% 29% 25% 10% 2	492
	21st to end	Day	11% 11% 30% 29% 17% 1	500
May	1st to 10th	Day	14% 9% 31% 29% 14% 3	503
	11th to 20th	Day	13% 5% 27% 27% 19% 9%	527
	21st to end	Day	7% 5% 20% 34% 23% 11%	573
June	1st to 10th	Day	11% 4 13% 34% 27% 11%	682
	11th to 20th	Day	6% 2 12% 35% 33% 12%	730
	21st to end	Day	6% 2 10% 29% 36% 17%	730
July	1st to 10th	Day	4 2 8% 29% 41% 17%	721
	11th to 20th	Day	7% 3 3 19% 41% 27%	718
	21st to end	Day	8% 2 6% 23% 40% 20%	639
August	1st to 10th	Day	5% 2 7% 24% 37% 26%	486
	11th to 20th	Day	7% 1 5% 21% 41% 25%	479
	21st to end	Day	14% 1 7% 21% 31% 26%	539
September	1st to 10th	Day	8% 3 10% 23% 38% 18%	490
	11th to 20th	Day	10% 3 12% 20% 37% 18%	490
	21st to end	Day	11% 4 13% 30% 30% 12%	490
October	1st to 10th	Day	6% 5% 21% 36% 21% 10%	379
	11th to 20th	Day	9% 7% 24% 34% 20% 5%	300
	21st to end	Day	18% 9% 25% 25% 17% 6%	330
November	1st to 10th	Day	15% 7% 27% 36% 10% 4	300
	11th to 20th	Day	15% 13% 36% 23% 12% 1	300
	21st to end	Day	13% 19% 37% 14% 14% 3	300
December	1st to 10th	Day	21% 15% 37% 19% 7% 1	300
	11th to 20th	Day	18% 16% 35% 23% 6% 1	300
	21st to end	Day	20% 20% 34% 18% 8% 1	330
January	1st to 10th	Night	21% 14% 33% 27% 5%	1000
	11th to 20th	Night	21% 14% 33% 26% 7%	1000
	21st to end	Night	24% 13% 33% 27% 3	1035
February	1st to 10th	Night	21% 11% 36% 28% 5%	800
	11th to 20th	Night	25% 15% 31% 25% 4	783
	21st to end	Night	24% 16% 38% 21% 2	660
March	1st to 10th	Night	17% 15% 33% 30% 6%	744
	11th to 20th	Night	15% 10% 39% 28% 7% 1	600
	21st to end	Night	17% 8% 37% 29% 8%	660
April	1st to 10th	Night	15% 12% 35% 27% 11% 1	600
	11th to 20th	Night	13% 9% 38% 28% 11% 1	593
	21st to end	Night	10% 6% 33% 36% 14% 1	600
May	1st to 10th	Night	12% 4 30% 37% 16% 2	600
	11th to 20th	Night	10% 5% 24% 38% 20% 3	591
	21st to end	Night	7% 2 17% 37% 30% 6%	650
June	1st to 10th	Night	8% 2 11% 41% 32% 6%	600
	11th to 20th	Night	4 1 9% 35% 42% 9%	600
	21st to end	Night	5% 2 9% 25% 45% 14%	600
July	1st to 10th	Night	5% 1 6% 26% 49% 13%	585
	11th to 20th	Night	5% 1 5% 24% 47% 19%	582
	21st to end	Night	4 1 4 27% 50% 13%	624
August	1st to 10th	Night	3 1 4 24% 49% 20%	567
	11th to 20th	Night	6% 1 5% 23% 50% 15%	564
	21st to end	Night	11% 2 6% 25% 41% 17%	627
September	1st to 10th	Night	8% 2 9% 31% 43% 8%	570
	11th to 20th	Night	8% 3 9% 28% 44% 8%	601
	21st to end	Night	10% 2 11% 33% 37% 6%	760
October	1st to 10th	Night	6% 1 17% 38% 31% 7%	760
	11th to 20th	Night	12% 4 23% 35% 23% 3	760
	21st to end	Night	16% 6% 22% 32% 23% 3	836
November	1st to 10th	Night	14% 6% 21% 36% 20% 3	780
	11th to 20th	Night	14% 8% 29% 34% 15% 1	800
	21st to end	Night	16% 8% 31% 31% 13% 2	800
December	1st to 10th	Night	20% 8% 31% 32% 9%	800
	11th to 20th	Night	20% 10% 31% 31% 8%	825
	21st to end	Night	24% 12% 31% 27% 6%	1100

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