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 2024-03-28.

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 5% 5% 3 5% 5% 6% 8% 42%	79041
	Night	12% 6% 2 4 4 3 4 4 5% 7% 47%	80959
Transparency	Day	40% 6% 11% 19% 19% 6%	78772
	Night	36% 5% 11% 19% 21% 8%	80749
Seeing	Day	13% 9% 21% 25% 23% 11%	14107
	Night	14% 7% 24% 30% 21% 5%	24007

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% 12% 3 5% 4 2 3 3 5% 6% 41%	2847
	11th to 20th	Day	16% 7% 2 5% 4 3 3 3 5% 6% 47%	2850
	21st to end	Day	22% 9% 3 5% 4 2 3 3 4 5% 41%	3229
February	1st to 10th	Day	15% 10% 3 6% 5% 2 5% 4 4 5% 40%	1900
	11th to 20th	Day	21% 8% 3 4 4 2 4 3 5% 5% 40%	1848
	21st to end	Day	17% 7% 3 6% 7% 3 4 4 4 5% 39%	1570
March	1st to 10th	Day	15% 8% 3 6% 6% 2 5% 4 4 7% 40%	1967
	11th to 20th	Day	15% 7% 3 6% 5% 4 6% 5% 6% 8% 37%	2090
	21st to end	Day	12% 6% 2 6% 6% 4 5% 6% 6% 8% 40%	2365
April	1st to 10th	Day	10% 5% 3 5% 5% 3 5% 6% 6% 7% 45%	2160
	11th to 20th	Day	15% 7% 3 6% 5% 3 4 4 5% 7% 43%	2134
	21st to end	Day	8% 4 2 5% 5% 3 5% 5% 5% 9% 48%	2160
May	1st to 10th	Day	10% 5% 3 4 5% 4 6% 5% 6% 9% 44%	2160
	11th to 20th	Day	9% 6% 3 5% 6% 3 6% 5% 6% 9% 43%	2124
	21st to end	Day	7% 4 2 5% 6% 3 6% 6% 9% 9% 43%	2444
June	1st to 10th	Day	9% 4 1 5% 6% 5% 7% 7% 7% 11% 37%	2476
	11th to 20th	Day	5% 4 2 5% 6% 5% 7% 7% 7% 9% 43%	2520
	21st to end	Day	6% 3 2 6% 6% 5% 8% 7% 8% 10% 40%	2496
July	1st to 10th	Day	6% 4 3 6% 7% 5% 9% 9% 9% 10% 31%	2340
	11th to 20th	Day	8% 4 3 5% 6% 4 8% 8% 10% 11% 31%	2340
	21st to end	Day	8% 5% 3 6% 6% 4 8% 8% 10% 11% 31%	2451
August	1st to 10th	Day	5% 5% 2 5% 7% 4 7% 7% 9% 11% 38%	2148
	11th to 20th	Day	7% 5% 3 6% 8% 5% 8% 7% 8% 10% 34%	2125
	21st to end	Day	12% 4 2 5% 6% 4 6% 6% 6% 9% 39%	2376
September	1st to 10th	Day	8% 5% 2 6% 7% 3 6% 7% 5% 8% 42%	2160
	11th to 20th	Day	12% 5% 3 6% 5% 4 5% 5% 5% 6% 44%	2111
	21st to end	Day	9% 4 2 3 4 3 3 4 5% 8% 53%	1980
October	1st to 10th	Day	6% 3 1 4 5% 2 5% 4 4 6% 58%	1875
	11th to 20th	Day	8% 5% 2 5% 5% 3 4 3 5% 7% 54%	1800
	21st to end	Day	13% 6% 2 4 4 2 3 3 3 6% 56%	1980
November	1st to 10th	Day	10% 4 2 5% 4 3 4 4 4 5% 56%	1857
	11th to 20th	Day	11% 6% 3 4 4 3 3 5% 4 6% 52%	1710
	21st to end	Day	15% 7% 2 5% 5% 2 4 4 4 6% 47%	1710
December	1st to 10th	Day	17% 8% 2 5% 5% 3 4 4 5% 7% 41%	1710
	11th to 20th	Day	15% 9% 3 6% 4 3 4 3 4 6% 42%	2108
	21st to end	Day	14% 7% 2 5% 5% 2 4 5% 6% 8% 42%	2920
January	1st to 10th	Night	17% 10% 2 4 3 2 4 3 4 5% 45%	4108
	11th to 20th	Night	14% 8% 3 6% 4 2 3 3 4 5% 48%	4120
	21st to end	Night	25% 9% 3 4 3 2 3 2 3 4 43%	4432
February	1st to 10th	Night	17% 9% 3 5% 5% 2 4 4 4 6% 41%	2280
	11th to 20th	Night	19% 7% 3 4 4 2 4 3 4 5% 45%	2218
	21st to end	Night	20% 7% 3 6% 4 2 3 4 4 5% 41%	1884
March	1st to 10th	Night	14% 6% 3 5% 4 3 3 4 5% 7% 45%	2227
	11th to 20th	Night	13% 6% 3 5% 6% 3 4 6% 6% 8% 41%	2090
	21st to end	Night	13% 6% 2 4 5% 3 4 5% 5% 7% 47%	2144
April	1st to 10th	Night	12% 4 3 4 5% 3 4 5% 6% 6% 48%	1800
	11th to 20th	Night	13% 5% 2 3 4 3 5% 5% 6% 7% 48%	1775
	21st to end	Night	7% 4 3 4 4 3 4 4 6% 7% 53%	1800
May	1st to 10th	Night	8% 4 2 3 3 3 4 4 5% 10% 53%	1800
	11th to 20th	Night	7% 5% 2 5% 6% 2 4 5% 7% 10% 46%	1769
	21st to end	Night	5% 4 2 4 5% 3 5% 5% 8% 12% 48%	1827
June	1st to 10th	Night	6% 5% 2 5% 7% 4 5% 4 7% 11% 43%	1478
	11th to 20th	Night	3 2 2 3 4 3 5% 6% 8% 12% 51%	1440
	21st to end	Night	4 4 2 5% 5% 3 6% 6% 7% 12% 47%	1457
July	1st to 10th	Night	6% 3 2 6% 6% 4 5% 6% 8% 13% 43%	1620
	11th to 20th	Night	4 4 2 4 6% 4 7% 6% 8% 11% 45%	1620
	21st to end	Night	3 4 2 4 5% 3 6% 7% 9% 12% 47%	1866
August	1st to 10th	Night	2 2 2 4 4 3 5% 6% 8% 15% 49%	1790
	11th to 20th	Night	5% 4 2 5% 5% 3 5% 6% 8% 13% 44%	1776
	21st to end	Night	9% 4 2 5% 4 4 6% 5% 7% 10% 44%	1980
September	1st to 10th	Night	7% 4 2 5% 5% 3 5% 7% 6% 9% 46%	1800
	11th to 20th	Night	7% 6% 2 6% 5% 3 5% 5% 6% 7% 47%	1829
	21st to end	Night	9% 4 2 3 4 3 4 5% 5% 6% 55%	1980
October	1st to 10th	Night	6% 3 2 3 4 2 4 4 4 6% 62%	2079
	11th to 20th	Night	11% 5% 1 4 4 2 3 4 5% 6% 54%	2160
	21st to end	Night	14% 6% 2 3 4 2 3 2 4 4 56%	2376
November	1st to 10th	Night	11% 4 2 4 3 2 3 3 4 6% 59%	2220
	11th to 20th	Night	12% 5% 2 4 3 2 3 4 4 6% 55%	2469
	21st to end	Night	13% 6% 2 4 4 3 4 4 5% 6% 49%	2470
December	1st to 10th	Night	17% 6% 3 5% 5% 3 4 4 4 6% 44%	2470
	11th to 20th	Night	14% 7% 2 5% 6% 4 4 3 4 5% 45%	3078
	21st to end	Night	17% 11% 3 5% 4 3 3 3 5% 6% 41%	4727

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	44% 3 4 18% 25% 5%	2848
	11th to 20th	Day	39% 3 8% 22% 23% 6%	2850
	21st to end	Day	48% 3 6% 14% 22% 8%	3229
February	1st to 10th	Day	48% 3 7% 16% 17% 9%	1900
	11th to 20th	Day	47% 3 5% 17% 20% 8%	1858
	21st to end	Day	48% 4 7% 14% 19% 9%	1570
March	1st to 10th	Day	47% 3 8% 14% 19% 9%	1967
	11th to 20th	Day	46% 4 9% 16% 18% 6%	2090
	21st to end	Day	42% 5% 9% 19% 20% 4	2365
April	1st to 10th	Day	37% 5% 9% 23% 18% 7%	2160
	11th to 20th	Day	43% 4 7% 17% 24% 6%	2134
	21st to end	Day	34% 5% 8% 26% 25% 2	2160
May	1st to 10th	Day	38% 6% 11% 19% 21% 5%	2160
	11th to 20th	Day	38% 6% 14% 26% 15% 1	2128
	21st to end	Day	35% 7% 16% 25% 16% 1	2444
June	1st to 10th	Day	41% 8% 14% 24% 13% 2	2476
	11th to 20th	Day	36% 8% 16% 23% 14% 3	2520
	21st to end	Day	38% 9% 16% 22% 13% 2	2496
July	1st to 10th	Day	42% 10% 20% 19% 7% 2	2276
	11th to 20th	Day	40% 13% 23% 18% 6% 2	2271
	21st to end	Day	41% 10% 18% 21% 9% 1	2315
August	1st to 10th	Day	35% 10% 21% 26% 8%	2136
	11th to 20th	Day	43% 10% 16% 19% 9% 3	2125
	21st to end	Day	41% 8% 16% 20% 11% 4	2376
September	1st to 10th	Day	38% 8% 14% 18% 17% 6%	2160
	11th to 20th	Day	41% 5% 10% 16% 20% 7%	2111
	21st to end	Day	30% 4 11% 24% 21% 10%	1980
October	1st to 10th	Day	27% 6% 8% 21% 26% 12%	1875
	11th to 20th	Day	31% 5% 5% 17% 29% 13%	1800
	21st to end	Day	32% 3 5% 17% 31% 12%	1980
November	1st to 10th	Day	32% 4 6% 17% 31% 11%	1857
	11th to 20th	Day	35% 3 6% 16% 28% 13%	1710
	21st to end	Day	40% 3 7% 18% 23% 10%	1710
December	1st to 10th	Day	43% 4 9% 19% 16% 9%	1710
	11th to 20th	Day	46% 4 6% 15% 23% 7%	2105
	21st to end	Day	40% 4 7% 21% 25% 3	2920
January	1st to 10th	Night	43% 3 5% 14% 26% 9%	4108
	11th to 20th	Night	40% 4 6% 19% 20% 11%	4120
	21st to end	Night	48% 2 4 16% 23% 6%	4432
February	1st to 10th	Night	45% 3 6% 16% 21% 9%	2280
	11th to 20th	Night	43% 4 6% 17% 21% 10%	2219
	21st to end	Night	47% 5% 6% 14% 17% 12%	1884
March	1st to 10th	Night	40% 4 7% 17% 21% 11%	2227
	11th to 20th	Night	42% 5% 11% 17% 18% 7%	2090
	21st to end	Night	37% 4 10% 20% 23% 6%	2144
April	1st to 10th	Night	36% 5% 11% 19% 20% 9%	1800
	11th to 20th	Night	36% 3 9% 21% 22% 9%	1775
	21st to end	Night	30% 4 8% 25% 28% 5%	1800
May	1st to 10th	Night	28% 5% 11% 27% 23% 6%	1800
	11th to 20th	Night	32% 6% 15% 25% 18% 2	1770
	21st to end	Night	27% 7% 17% 27% 18% 2	1828
June	1st to 10th	Night	35% 6% 17% 25% 16% 1	1478
	11th to 20th	Night	24% 8% 19% 29% 16% 4	1440
	21st to end	Night	29% 8% 21% 24% 16% 3	1457
July	1st to 10th	Night	32% 10% 23% 24% 9% 3	1575
	11th to 20th	Night	29% 11% 27% 23% 7% 2	1566
	21st to end	Night	27% 9% 28% 24% 10% 1	1762
August	1st to 10th	Night	23% 11% 27% 27% 11%	1778
	11th to 20th	Night	31% 11% 21% 22% 12% 3	1776
	21st to end	Night	34% 9% 21% 18% 14% 4	1980
September	1st to 10th	Night	33% 8% 14% 22% 18% 6%	1800
	11th to 20th	Night	35% 6% 13% 17% 20% 9%	1829
	21st to end	Night	29% 5% 10% 24% 21% 11%	1980
October	1st to 10th	Night	23% 5% 9% 22% 25% 16%	2079
	11th to 20th	Night	31% 3 6% 17% 27% 15%	2160
	21st to end	Night	34% 2 5% 16% 26% 17%	2376
November	1st to 10th	Night	29% 3 6% 18% 30% 13%	2220
	11th to 20th	Night	32% 3 7% 16% 27% 15%	2469
	21st to end	Night	37% 3 7% 20% 21% 13%	2470
December	1st to 10th	Night	42% 4 9% 18% 20% 7%	2470
	11th to 20th	Night	43% 3 6% 13% 27% 8%	3080
	21st to end	Night	45% 4 6% 16% 25% 5%	4727

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% 34% 15% 3 1	270
	11th to 20th	Day	26% 18% 34% 15% 6% 1	270
	21st to end	Day	25% 23% 35% 14% 3	297
February	1st to 10th	Day	19% 25% 34% 15% 6% 1	270
	11th to 20th	Day	33% 16% 36% 13% 2 1	270
	21st to end	Day	23% 28% 37% 10% 1	225
March	1st to 10th	Day	24% 16% 40% 16% 4	270
	11th to 20th	Day	21% 23% 34% 17% 4	270
	21st to end	Day	19% 18% 33% 24% 5% 1	395
April	1st to 10th	Day	13% 16% 34% 25% 10% 1	420
	11th to 20th	Day	21% 15% 27% 25% 10% 2	412
	21st to end	Day	11% 11% 32% 30% 16%	420
May	1st to 10th	Day	13% 9% 30% 29% 15% 3	423
	11th to 20th	Day	12% 3 24% 28% 22% 11%	447
	21st to end	Day	7% 4 18% 33% 25% 13%	485
June	1st to 10th	Day	12% 3 12% 33% 28% 13%	586
	11th to 20th	Day	5% 2 12% 35% 33% 12%	630
	21st to end	Day	7% 2 10% 31% 35% 15%	630
July	1st to 10th	Day	5% 1 7% 30% 40% 17%	621
	11th to 20th	Day	7% 3 3 19% 41% 27%	618
	21st to end	Day	7% 2 6% 23% 40% 22%	589
August	1st to 10th	Day	6% 2 7% 21% 38% 27%	446
	11th to 20th	Day	8% 1 4 21% 42% 25%	439
	21st to end	Day	15% 2 7% 19% 31% 26%	495
September	1st to 10th	Day	6% 2 10% 24% 38% 19%	450
	11th to 20th	Day	9% 4 11% 20% 38% 19%	450
	21st to end	Day	11% 3 11% 31% 32% 12%	450
October	1st to 10th	Day	7% 5% 19% 36% 22% 11%	345
	11th to 20th	Day	10% 7% 24% 33% 21% 6%	270
	21st to end	Day	20% 10% 27% 25% 15% 4	297
November	1st to 10th	Day	14% 7% 26% 37% 11% 4	270
	11th to 20th	Day	15% 13% 36% 24% 11% 1	270
	21st to end	Day	13% 20% 36% 15% 14% 2	270
December	1st to 10th	Day	21% 16% 37% 19% 7% 1	270
	11th to 20th	Day	20% 15% 35% 23% 7% 1	270
	21st to end	Day	20% 21% 34% 18% 7% 1	297
January	1st to 10th	Night	21% 14% 32% 27% 5%	950
	11th to 20th	Night	21% 14% 33% 26% 7%	950
	21st to end	Night	23% 14% 33% 27% 4	984
February	1st to 10th	Night	22% 11% 35% 28% 5%	760
	11th to 20th	Night	24% 15% 31% 25% 5%	743
	21st to end	Night	24% 17% 37% 21% 1	628
March	1st to 10th	Night	17% 14% 32% 30% 6%	707
	11th to 20th	Night	15% 10% 38% 29% 7% 1	570
	21st to end	Night	17% 9% 36% 29% 8%	615
April	1st to 10th	Night	14% 11% 35% 28% 12% 1	540
	11th to 20th	Night	14% 8% 36% 29% 12% 1	533
	21st to end	Night	10% 6% 34% 36% 14% 1	540
May	1st to 10th	Night	11% 4 30% 37% 16% 2	540
	11th to 20th	Night	8% 4 23% 40% 22% 3	531
	21st to end	Night	7% 1 16% 37% 32% 7%	584
June	1st to 10th	Night	8% 1 11% 41% 32% 7%	540
	11th to 20th	Night	4 1 9% 35% 43% 10%	540
	21st to end	Night	5% 2 10% 25% 44% 14%	540
July	1st to 10th	Night	5% 1 6% 28% 46% 13%	525
	11th to 20th	Night	5% 1 5% 24% 46% 19%	522
	21st to end	Night	4 1 4 28% 50% 14%	591
August	1st to 10th	Night	3 1 4 23% 49% 21%	537
	11th to 20th	Night	6% 1 5% 23% 50% 15%	534
	21st to end	Night	11% 2 6% 24% 40% 18%	594
September	1st to 10th	Night	8% 1 9% 31% 44% 8%	540
	11th to 20th	Night	8% 2 9% 28% 44% 8%	569
	21st to end	Night	11% 2 11% 33% 37% 6%	720
October	1st to 10th	Night	7% 1 17% 37% 32% 7%	720
	11th to 20th	Night	12% 4 23% 33% 24% 3	720
	21st to end	Night	16% 6% 23% 31% 22% 3	792
November	1st to 10th	Night	13% 6% 20% 37% 20% 3	740
	11th to 20th	Night	13% 8% 29% 33% 15% 1	760
	21st to end	Night	16% 8% 31% 31% 13% 2	760
December	1st to 10th	Night	19% 8% 31% 32% 10%	760
	11th to 20th	Night	20% 10% 31% 31% 9%	783
	21st to end	Night	24% 12% 31% 27% 6%	1045

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