Gulfport
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Gulfport clear sky chart from 2005-11-06 to 2026-07-31.

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% 5% 2 6% 4 5% 5% 4 7% 9% 42%	137179
	Night	11% 6% 2 6% 4 4 5% 4 6% 9% 44%	135831
Transparency	Day	24% 38% 10% 13% 11% 5%	140966
	Night	24% 37% 9% 12% 11% 6%	140121
Seeing	Day	13% 6% 20% 27% 23% 12%	16471
	Night	13% 5% 19% 30% 26% 8%	26334

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	15% 5% 3 6% 4 5% 5% 3 5% 6% 43%	5856
	11th to 20th	Day	11% 6% 2 5% 4 3 4 3 5% 6% 51%	5880
	21st to end	Day	20% 8% 3 7% 4 4 4 4 5% 6% 37%	6436
February	1st to 10th	Day	15% 9% 3 7% 5% 4 3 3 4 5% 42%	2100
	11th to 20th	Day	15% 7% 2 5% 4 4 4 4 5% 7% 42%	2048
	21st to end	Day	16% 8% 2 6% 5% 5% 4 4 7% 6% 37%	1730
March	1st to 10th	Day	17% 8% 3 8% 4 4 4 4 5% 6% 38%	4580
	11th to 20th	Day	13% 6% 2 5% 4 3 4 3 5% 7% 48%	5029
	21st to end	Day	14% 7% 3 6% 4 4 4 4 5% 6% 42%	6023
April	1st to 10th	Day	10% 6% 3 5% 5% 5% 4 4 6% 8% 43%	2520
	11th to 20th	Day	11% 7% 2 5% 5% 3 5% 4 6% 8% 43%	2494
	21st to end	Day	7% 6% 2 4 3 5% 5% 4 6% 9% 50%	2520
May	1st to 10th	Day	18% 7% 2 6% 4 4 5% 4 7% 9% 34%	7021
	11th to 20th	Day	8% 4 2 5% 5% 5% 5% 5% 7% 10% 45%	7031
	21st to end	Day	6% 5% 2 6% 5% 5% 5% 5% 10% 13% 38%	8126
June	1st to 10th	Day	8% 5% 3 7% 6% 5% 7% 6% 8% 10% 35%	2730
	11th to 20th	Day	4 4 2 5% 5% 6% 6% 6% 9% 12% 40%	2730
	21st to end	Day	6% 6% 2 7% 5% 6% 6% 8% 10% 14% 30%	2678
July	1st to 10th	Day	4 4 2 6% 5% 7% 8% 7% 11% 15% 33%	5560
	11th to 20th	Day	4 4 2 6% 6% 6% 6% 5% 9% 13% 40%	5560
	21st to end	Day	3 3 2 8% 6% 6% 7% 7% 11% 14% 32%	6042
August	1st to 10th	Day	3 2 1 4 4 5% 6% 6% 9% 13% 48%	3905
	11th to 20th	Day	5% 3 2 5% 4 5% 6% 6% 9% 13% 42%	3849
	21st to end	Day	6% 6% 3 9% 6% 6% 7% 6% 7% 9% 34%	4312
September	1st to 10th	Day	9% 5% 2 6% 4 5% 7% 5% 9% 10% 38%	2400
	11th to 20th	Day	8% 6% 2 5% 4 5% 5% 5% 8% 10% 43%	2270
	21st to end	Day	7% 4 2 4 4 5% 5% 5% 7% 9% 50%	2200
October	1st to 10th	Day	6% 3 1 4 3 4 5% 4 6% 7% 57%	2200
	11th to 20th	Day	5% 3 2 4 3 4 4 2 6% 7% 60%	2050
	21st to end	Day	9% 4 2 4 3 4 4 2 4 6% 58%	2200
November	1st to 10th	Day	9% 4 1 4 3 2 4 4 5% 7% 58%	2021
	11th to 20th	Day	11% 4 1 4 4 3 3 3 5% 5% 58%	1890
	21st to end	Day	11% 7% 2 5% 4 4 4 4 5% 7% 47%	1890
December	1st to 10th	Day	16% 6% 2 6% 4 4 4 3 5% 6% 43%	3020
	11th to 20th	Day	9% 7% 2 6% 4 4 5% 4 6% 8% 47%	3463
	21st to end	Day	17% 8% 3 7% 4 4 3 3 4 6% 41%	4815
January	1st to 10th	Night	14% 6% 2 6% 4 4 4 3 5% 7% 44%	7037
	11th to 20th	Night	16% 7% 3 6% 3 3 3 2 4 7% 46%	7080
	21st to end	Night	20% 7% 3 6% 4 4 4 3 5% 7% 36%	7745
February	1st to 10th	Night	13% 8% 2 5% 5% 4 4 3 5% 6% 44%	2520
	11th to 20th	Night	19% 7% 3 6% 4 4 3 3 5% 6% 40%	2458
	21st to end	Night	15% 9% 2 6% 4 5% 4 3 5% 6% 40%	2076
March	1st to 10th	Night	19% 10% 3 7% 4 3 4 3 5% 6% 37%	5493
	11th to 20th	Night	11% 6% 2 5% 4 4 4 3 5% 7% 48%	5191
	21st to end	Night	13% 6% 2 5% 3 4 4 4 5% 6% 47%	5134
April	1st to 10th	Night	11% 7% 3 7% 4 4 4 3 6% 6% 45%	2100
	11th to 20th	Night	10% 5% 2 6% 4 4 5% 4 5% 7% 47%	2075
	21st to end	Night	6% 4 2 4 3 3 4 4 6% 8% 55%	2100
May	1st to 10th	Night	18% 7% 3 7% 4 3 4 4 5% 8% 37%	5832
	11th to 20th	Night	10% 5% 2 6% 4 4 5% 4 7% 9% 43%	5829
	21st to end	Night	4 5% 2 7% 5% 5% 6% 6% 8% 14% 38%	6003
June	1st to 10th	Night	7% 6% 2 6% 5% 5% 7% 5% 8% 10% 40%	1890
	11th to 20th	Night	3 4 2 5% 4 4 6% 6% 9% 14% 43%	1890
	21st to end	Night	6% 5% 2 7% 5% 5% 5% 6% 9% 12% 38%	1932
July	1st to 10th	Night	3 4 2 6% 5% 6% 7% 6% 9% 15% 38%	4618
	11th to 20th	Night	1 3 2 6% 5% 5% 5% 5% 9% 12% 48%	4617
	21st to end	Night	3 4 2 6% 6% 7% 7% 7% 11% 15% 33%	5029
August	1st to 10th	Night	2 3 1 3 3 3 4 5% 7% 14% 55%	3244
	11th to 20th	Night	3 2 2 5% 4 4 6% 6% 9% 15% 43%	3200
	21st to end	Night	5% 4 2 7% 6% 7% 7% 6% 8% 10% 39%	3586
September	1st to 10th	Night	7% 5% 3 7% 6% 5% 6% 6% 7% 9% 38%	2000
	11th to 20th	Night	8% 6% 2 5% 4 4 4 4 7% 10% 45%	2107
	21st to end	Night	6% 5% 2 5% 4 4 4 3 7% 9% 52%	2200
October	1st to 10th	Night	7% 4 2 6% 3 3 4 3 5% 7% 56%	2200
	11th to 20th	Night	6% 3 1 4 3 3 3 3 5% 7% 62%	2345
	21st to end	Night	9% 5% 2 5% 3 4 3 3 5% 6% 56%	2640
November	1st to 10th	Night	9% 4 2 5% 3 4 4 3 5% 6% 55%	2492
	11th to 20th	Night	11% 5% 2 5% 4 3 3 3 5% 5% 55%	2730
	21st to end	Night	9% 6% 2 6% 3 5% 4 3 5% 7% 49%	2730
December	1st to 10th	Night	13% 6% 3 6% 5% 5% 4 4 5% 6% 44%	4380
	11th to 20th	Night	11% 6% 2 5% 4 3 4 4 4 6% 51%	4952
	21st to end	Night	17% 8% 4 7% 4 4 3 3 4 4 42%	6376

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	31% 23% 9% 14% 18% 5%	5857
	11th to 20th	Day	27% 21% 4 15% 23% 10%	5880
	21st to end	Day	38% 24% 6% 9% 12% 10%	6436
February	1st to 10th	Day	20% 59% 3 5% 9% 5%	2100
	11th to 20th	Day	17% 59% 5% 9% 8% 2	2058
	21st to end	Day	17% 60% 4 6% 9% 4	1730
March	1st to 10th	Day	37% 29% 6% 13% 8% 7%	4580
	11th to 20th	Day	25% 30% 5% 12% 16% 11%	5029
	21st to end	Day	32% 30% 9% 13% 9% 7%	6025
April	1st to 10th	Day	18% 60% 4 7% 8% 3	2520
	11th to 20th	Day	16% 60% 4 8% 9% 3	2494
	21st to end	Day	13% 60% 6% 10% 7% 3	2520
May	1st to 10th	Day	38% 25% 13% 13% 8% 3	7056
	11th to 20th	Day	23% 26% 17% 21% 11% 2	7035
	21st to end	Day	29% 29% 17% 19% 6% 1	8140
June	1st to 10th	Day	16% 62% 8% 9% 5%	2730
	11th to 20th	Day	17% 63% 8% 7% 4	2730
	21st to end	Day	17% 61% 11% 8% 3	2678
July	1st to 10th	Day	24% 35% 24% 15% 2	5500
	11th to 20th	Day	23% 36% 32% 8%	5497
	21st to end	Day	26% 35% 19% 18% 1	5872
August	1st to 10th	Day	11% 39% 11% 21% 18% 1	3893
	11th to 20th	Day	14% 41% 16% 21% 8% 1	3885
	21st to end	Day	27% 42% 10% 11% 9% 1	4311
September	1st to 10th	Day	16% 60% 9% 8% 5% 2	2400
	11th to 20th	Day	10% 59% 10% 11% 9% 2	2270
	21st to end	Day	12% 59% 7% 14% 6% 2	2200
October	1st to 10th	Day	17% 36% 6% 8% 11% 22%	3590
	11th to 20th	Day	5% 36% 2 13% 19% 25%	3316
	21st to end	Day	10% 36% 3 6% 30% 15%	3538
November	1st to 10th	Day	16% 54% 5% 11% 9% 5%	2021
	11th to 20th	Day	17% 54% 4 9% 12% 5%	1890
	21st to end	Day	17% 54% 5% 9% 8% 6%	1890
December	1st to 10th	Day	31% 35% 5% 9% 17% 4	3020
	11th to 20th	Day	20% 32% 7% 15% 17% 9%	3460
	21st to end	Day	33% 26% 5% 11% 19% 5%	4815
January	1st to 10th	Night	33% 22% 9% 12% 17% 7%	7038
	11th to 20th	Night	32% 21% 4 13% 21% 9%	7080
	21st to end	Night	39% 23% 5% 11% 15% 7%	7745
February	1st to 10th	Night	17% 59% 3 7% 9% 4	2520
	11th to 20th	Night	19% 59% 3 8% 8% 3	2459
	21st to end	Night	18% 60% 5% 6% 8% 4	2076
March	1st to 10th	Night	39% 29% 6% 9% 11% 5%	5493
	11th to 20th	Night	26% 29% 6% 10% 15% 14%	5191
	21st to end	Night	29% 30% 8% 15% 11% 7%	5134
April	1st to 10th	Night	18% 60% 4 5% 8% 5%	2100
	11th to 20th	Night	15% 61% 3 9% 9% 3	2075
	21st to end	Night	14% 60% 5% 10% 8% 3	2100
May	1st to 10th	Night	39% 25% 11% 12% 10% 3	5862
	11th to 20th	Night	29% 26% 12% 22% 10% 1	5830
	21st to end	Night	29% 28% 20% 18% 5%	6014
June	1st to 10th	Night	15% 61% 8% 10% 5% 1	1890
	11th to 20th	Night	15% 62% 10% 9% 4	1890
	21st to end	Night	14% 62% 12% 7% 4	1932
July	1st to 10th	Night	22% 33% 27% 15% 3	4570
	11th to 20th	Night	20% 34% 37% 9%	4560
	21st to end	Night	25% 38% 15% 21% 1	4885
August	1st to 10th	Night	9% 38% 13% 22% 16% 1	3232
	11th to 20th	Night	14% 40% 19% 22% 6%	3230
	21st to end	Night	23% 43% 12% 14% 7% 2	3586
September	1st to 10th	Night	16% 59% 9% 9% 6% 2	2000
	11th to 20th	Night	11% 58% 10% 9% 9% 3	2107
	21st to end	Night	13% 57% 9% 14% 5% 2	2200
October	1st to 10th	Night	21% 37% 7% 8% 13% 15%	3590
	11th to 20th	Night	6% 35% 3 13% 18% 24%	3818
	21st to end	Night	10% 35% 3 5% 30% 16%	4252
November	1st to 10th	Night	19% 53% 5% 9% 9% 5%	2492
	11th to 20th	Night	17% 54% 3 8% 12% 6%	2730
	21st to end	Night	16% 55% 4 10% 10% 5%	2730
December	1st to 10th	Night	30% 35% 5% 9% 14% 7%	4380
	11th to 20th	Night	21% 32% 5% 17% 15% 10%	4954
	21st to end	Night	35% 27% 5% 11% 18% 5%	6376

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% 13% 36% 23% 7% 1	330
	11th to 20th	Day	17% 14% 35% 24% 8% 2	330
	21st to end	Day	22% 11% 38% 23% 5%	363
February	1st to 10th	Day	22% 12% 36% 22% 7% 1	330
	11th to 20th	Day	25% 14% 34% 18% 8% 1	330
	21st to end	Day	18% 12% 48% 18% 4	273
March	1st to 10th	Day	18% 14% 34% 28% 7%	330
	11th to 20th	Day	18% 14% 38% 21% 8% 1	330
	21st to end	Day	18% 8% 33% 29% 11% 1	557
April	1st to 10th	Day	17% 9% 35% 26% 12% 1	540
	11th to 20th	Day	17% 11% 31% 26% 13% 2	532
	21st to end	Day	9% 6% 30% 31% 19% 4	540
May	1st to 10th	Day	16% 6% 27% 31% 17% 4	543
	11th to 20th	Day	10% 5% 21% 33% 22% 9%	567
	21st to end	Day	8% 3 17% 35% 27% 11%	617
June	1st to 10th	Day	11% 2 12% 32% 27% 16%	570
	11th to 20th	Day	9% 3 11% 30% 30% 17%	570
	21st to end	Day	9% 2 7% 28% 31% 23%	570
July	1st to 10th	Day	9% 1 3 22% 35% 30%	565
	11th to 20th	Day	9% 3 3 17% 35% 33%	564
	21st to end	Day	6% 1 3 26% 39% 25%	616
August	1st to 10th	Day	6% 2 2 20% 40% 31%	526
	11th to 20th	Day	8% 2 2 20% 35% 34%	519
	21st to end	Day	9% 2 8% 22% 35% 25%	583
September	1st to 10th	Day	10% 3 4 24% 36% 23%	530
	11th to 20th	Day	12% 2 8% 24% 37% 18%	530
	21st to end	Day	8% 4 8% 31% 32% 16%	530
October	1st to 10th	Day	8% 3 16% 36% 27% 9%	530
	11th to 20th	Day	5% 2 22% 36% 23% 12%	380
	21st to end	Day	15% 6% 21% 31% 20% 6%	363
November	1st to 10th	Day	14% 4 24% 34% 20% 4	330
	11th to 20th	Day	17% 5% 29% 29% 15% 5%	330
	21st to end	Day	16% 8% 33% 26% 13% 4	330
December	1st to 10th	Day	21% 6% 31% 29% 11% 3	330
	11th to 20th	Day	19% 10% 34% 26% 11% 1	330
	21st to end	Day	25% 8% 28% 24% 12% 3	363
January	1st to 10th	Night	18% 10% 32% 33% 7%	840
	11th to 20th	Night	17% 8% 30% 35% 9%	840
	21st to end	Night	23% 9% 32% 31% 5%	924
February	1st to 10th	Night	18% 9% 33% 33% 8%	840
	11th to 20th	Night	23% 11% 29% 27% 9%	823
	21st to end	Night	20% 11% 34% 29% 6%	692
March	1st to 10th	Night	19% 9% 30% 33% 9%	840
	11th to 20th	Night	15% 6% 30% 32% 16% 1	679
	21st to end	Night	15% 6% 26% 36% 16% 1	693
April	1st to 10th	Night	16% 7% 27% 34% 15% 1	630
	11th to 20th	Night	14% 5% 29% 30% 21% 2	623
	21st to end	Night	10% 3 21% 39% 24% 2	630
May	1st to 10th	Night	12% 3 18% 39% 26% 2	630
	11th to 20th	Night	8% 2 15% 39% 30% 6%	621
	21st to end	Night	5% 2 9% 34% 41% 9%	683
June	1st to 10th	Night	9% 2 8% 26% 43% 12%	630
	11th to 20th	Night	4 2 5% 26% 47% 16%	630
	21st to end	Night	7% 1 5% 22% 44% 21%	630
July	1st to 10th	Night	6% 1 2 14% 51% 25%	615
	11th to 20th	Night	4 1 1 9% 46% 39%	612
	21st to end	Night	4 2 2 17% 48% 26%	687
August	1st to 10th	Night	3 1 1 11% 49% 35%	597
	11th to 20th	Night	5% 1 1 10% 49% 34%	594
	21st to end	Night	8% 2 4 16% 45% 25%	660
September	1st to 10th	Night	10% 1 5% 17% 45% 23%	600
	11th to 20th	Night	10% 2 7% 24% 46% 12%	707
	21st to end	Night	8% 2 7% 32% 41% 9%	800
October	1st to 10th	Night	8% 2 14% 37% 34% 5%	800
	11th to 20th	Night	8% 4 15% 35% 30% 7%	800
	21st to end	Night	12% 4 18% 38% 26% 3	880
November	1st to 10th	Night	12% 5% 16% 39% 25% 3	820
	11th to 20th	Night	15% 4 24% 37% 18% 2	840
	21st to end	Night	12% 7% 26% 36% 17% 2	840
December	1st to 10th	Night	18% 6% 28% 30% 16% 1	840
	11th to 20th	Night	18% 6% 25% 36% 13% 1	840
	21st to end	Night	26% 7% 27% 29% 11% 1	924

Page generated at 2026-07-28 02:25:24. Version ac07

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