Lemon Bay Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lemon Bay Park clear sky chart from 2005-11-06 to 2026-09-29.

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	6% 4 2 5% 4 5% 5% 5% 7% 11% 46%	148519
	Night	7% 5% 2 6% 5% 5% 5% 5% 7% 10% 43%	142895
Transparency	Day	22% 35% 17% 15% 8% 3	152278
	Night	25% 36% 13% 15% 9% 3	147207
Seeing	Day	7% 3 15% 26% 29% 20%	18131
	Night	8% 3 15% 33% 30% 11%	28137

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	6% 5% 2 5% 3 3 4 3 6% 10% 53%	5258
	11th to 20th	Day	17% 8% 3 7% 4 4 4 4 5% 7% 35%	5280
	21st to end	Day	12% 5% 2 5% 3 4 4 3 6% 8% 48%	6394
February	1st to 10th	Day	9% 4 3 5% 4 4 4 4 6% 7% 52%	2100
	11th to 20th	Day	5% 5% 2 4 3 3 4 3 5% 8% 59%	2048
	21st to end	Day	6% 5% 1 4 3 3 4 4 6% 9% 56%	1809
March	1st to 10th	Day	6% 4 2 6% 4 5% 5% 4 5% 7% 53%	5045
	11th to 20th	Day	4 3 1 5% 3 3 3 3 5% 8% 62%	5090
	21st to end	Day	6% 3 1 4 4 4 4 4 5% 8% 55%	5586
April	1st to 10th	Day	5% 3 1 4 3 3 5% 3 7% 11% 56%	2310
	11th to 20th	Day	5% 3 2 5% 3 4 4 4 6% 8% 56%	2286
	21st to end	Day	4 2 1 3 3 3 5% 4 6% 9% 59%	2457
May	1st to 10th	Day	2 2 1 3 2 3 3 3 6% 10% 63%	7552
	11th to 20th	Day	6% 4 1 4 4 4 4 3 6% 9% 54%	7626
	21st to end	Day	3 3 1 3 3 3 4 4 7% 12% 57%	8391
June	1st to 10th	Day	10% 7% 3 7% 5% 5% 5% 6% 8% 12% 33%	2730
	11th to 20th	Day	6% 5% 2 6% 5% 5% 6% 6% 11% 13% 35%	2730
	21st to end	Day	6% 5% 2 7% 7% 6% 6% 5% 10% 14% 33%	2730
July	1st to 10th	Day	3 4 2 6% 5% 6% 8% 7% 11% 16% 32%	7680
	11th to 20th	Day	3 3 2 8% 7% 7% 9% 7% 12% 15% 28%	7680
	21st to end	Day	2 3 1 6% 5% 6% 8% 7% 11% 15% 36%	8340
August	1st to 10th	Day	5% 4 3 8% 6% 7% 8% 7% 10% 14% 29%	5860
	11th to 20th	Day	3 3 1 4 4 4 6% 5% 9% 14% 48%	5417
	21st to end	Day	4 3 2 7% 5% 6% 7% 6% 11% 14% 34%	5566
September	1st to 10th	Day	6% 5% 3 7% 7% 7% 9% 6% 9% 13% 29%	2310
	11th to 20th	Day	8% 6% 3 7% 5% 7% 7% 6% 9% 10% 34%	2310
	21st to end	Day	5% 4 2 7% 7% 6% 7% 6% 9% 11% 36%	2288
October	1st to 10th	Day	9% 5% 3 7% 5% 6% 5% 5% 6% 10% 39%	2200
	11th to 20th	Day	5% 4 2 6% 4 3 6% 4 6% 8% 51%	2052
	21st to end	Day	8% 5% 2 5% 4 4 4 3 7% 10% 50%	2200
November	1st to 10th	Day	6% 4 1 4 4 4 3 4 6% 8% 55%	2057
	11th to 20th	Day	7% 4 2 5% 5% 4 4 4 6% 9% 50%	2100
	21st to end	Day	6% 4 2 5% 3 5% 4 4 7% 8% 53%	1989
December	1st to 10th	Day	3 3 2 4 3 3 3 4 6% 8% 62%	3020
	11th to 20th	Day	7% 5% 2 6% 4 5% 5% 4 6% 8% 49%	3463
	21st to end	Day	10% 6% 3 8% 5% 5% 5% 4 6% 9% 38%	4565
January	1st to 10th	Night	5% 4 2 5% 4 4 4 4 6% 9% 52%	7635
	11th to 20th	Night	15% 8% 4 9% 5% 5% 5% 4 5% 7% 33%	7680
	21st to end	Night	11% 5% 2 6% 4 4 5% 4 6% 8% 45%	7769
February	1st to 10th	Night	9% 6% 3 6% 4 4 4 4 5% 7% 49%	2520
	11th to 20th	Night	8% 4 2 5% 4 3 4 4 6% 8% 52%	2458
	21st to end	Night	6% 5% 2 4 3 4 4 4 6% 8% 54%	1996
March	1st to 10th	Night	5% 5% 2 6% 4 4 4 3 6% 9% 52%	5028
	11th to 20th	Night	4 3 1 4 3 4 4 4 7% 9% 56%	5090
	21st to end	Night	8% 5% 2 6% 4 4 4 3 5% 9% 49%	5588
April	1st to 10th	Night	4 3 1 5% 4 3 5% 4 7% 10% 54%	2310
	11th to 20th	Night	4 4 1 5% 4 3 4 4 7% 8% 54%	2283
	21st to end	Night	4 3 2 5% 4 4 4 3 6% 8% 56%	2163
May	1st to 10th	Night	5% 3 2 6% 4 4 5% 4 7% 10% 51%	5343
	11th to 20th	Night	6% 4 2 6% 4 5% 4 4 6% 8% 51%	5234
	21st to end	Night	5% 3 2 6% 5% 5% 5% 5% 7% 10% 48%	5761
June	1st to 10th	Night	10% 6% 3 7% 5% 5% 5% 5% 7% 11% 35%	1890
	11th to 20th	Night	5% 5% 2 7% 6% 6% 6% 6% 9% 12% 36%	1890
	21st to end	Night	6% 5% 2 6% 6% 6% 6% 5% 10% 14% 34%	1890
July	1st to 10th	Night	4 5% 3 8% 8% 8% 9% 7% 10% 14% 25%	5278
	11th to 20th	Night	4 5% 3 9% 8% 8% 9% 7% 12% 13% 23%	5277
	21st to end	Night	4 5% 3 9% 7% 7% 8% 7% 10% 14% 27%	5736
August	1st to 10th	Night	4 6% 3 10% 7% 7% 8% 6% 9% 14% 26%	4268
	11th to 20th	Night	3 3 1 4 4 4 6% 5% 9% 16% 44%	4582
	21st to end	Night	5% 4 2 8% 7% 7% 10% 7% 11% 15% 24%	5559
September	1st to 10th	Night	6% 5% 2 8% 7% 6% 7% 6% 9% 14% 28%	2310
	11th to 20th	Night	8% 5% 3 7% 6% 6% 7% 6% 10% 10% 31%	2310
	21st to end	Night	8% 6% 3 9% 7% 6% 6% 5% 8% 10% 33%	2289
October	1st to 10th	Night	9% 5% 3 8% 5% 5% 6% 4 8% 10% 38%	2200
	11th to 20th	Night	6% 6% 2 6% 4 5% 4 4 7% 8% 48%	2345
	21st to end	Night	8% 5% 2 6% 4 5% 4 4 6% 9% 47%	2640
November	1st to 10th	Night	7% 5% 2 6% 5% 4 4 3 6% 8% 49%	2461
	11th to 20th	Night	8% 4 2 6% 5% 3 5% 3 5% 8% 51%	2520
	21st to end	Night	7% 5% 2 5% 4 4 4 4 6% 9% 49%	2627
December	1st to 10th	Night	4 3 1 3 3 3 3 3 5% 8% 63%	4380
	11th to 20th	Night	9% 6% 2 5% 4 4 4 4 6% 8% 50%	4952
	21st to end	Night	10% 7% 3 7% 5% 5% 6% 5% 7% 10% 35%	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	20% 22% 7% 22% 23% 5%	5259
	11th to 20th	Day	43% 21% 8% 13% 11% 5%	5280
	21st to end	Day	28% 22% 6% 25% 12% 7%	6394
February	1st to 10th	Day	10% 60% 6% 9% 9% 5%	2100
	11th to 20th	Day	7% 58% 4 14% 13% 4	2058
	21st to end	Day	11% 61% 6% 8% 10% 4	1809
March	1st to 10th	Day	25% 33% 9% 16% 14% 4	5045
	11th to 20th	Day	13% 31% 9% 16% 16% 16%	5090
	21st to end	Day	21% 29% 8% 22% 15% 6%	5586
April	1st to 10th	Day	8% 60% 8% 14% 7% 3	2310
	11th to 20th	Day	9% 60% 7% 7% 11% 7%	2286
	21st to end	Day	8% 60% 6% 12% 13% 1	2457
May	1st to 10th	Day	14% 24% 23% 28% 9% 2	7586
	11th to 20th	Day	21% 25% 19% 23% 12% 1	7630
	21st to end	Day	15% 25% 27% 26% 7%	8405
June	1st to 10th	Day	19% 63% 11% 7% 1	2730
	11th to 20th	Day	18% 64% 11% 7%	2730
	21st to end	Day	13% 62% 16% 8%	2730
July	1st to 10th	Day	32% 27% 35% 6%	7615
	11th to 20th	Day	35% 25% 33% 7%	7611
	21st to end	Day	29% 26% 30% 14% 1	8156
August	1st to 10th	Day	35% 31% 26% 6% 2	5847
	11th to 20th	Day	19% 29% 25% 23% 5%	5453
	21st to end	Day	27% 31% 33% 9%	5566
September	1st to 10th	Day	18% 61% 16% 5%	2310
	11th to 20th	Day	17% 59% 13% 8% 2	2310
	21st to end	Day	16% 59% 10% 10% 4 1	2288
October	1st to 10th	Day	38% 39% 13% 7% 3 1	3590
	11th to 20th	Day	15% 37% 7% 18% 21% 2	3318
	21st to end	Day	16% 36% 4 20% 18% 5%	3538
November	1st to 10th	Day	11% 55% 10% 13% 7% 4	2057
	11th to 20th	Day	16% 55% 5% 10% 8% 5%	2100
	21st to end	Day	14% 56% 5% 11% 9% 5%	1989
December	1st to 10th	Day	11% 35% 12% 19% 16% 7%	3020
	11th to 20th	Day	23% 31% 7% 14% 16% 8%	3460
	21st to end	Day	33% 28% 11% 17% 9% 1	4565
January	1st to 10th	Night	22% 23% 7% 23% 21% 4	7636
	11th to 20th	Night	44% 22% 9% 12% 9% 5%	7680
	21st to end	Night	28% 23% 9% 21% 12% 7%	7769
February	1st to 10th	Night	13% 59% 5% 11% 8% 4	2520
	11th to 20th	Night	10% 58% 4 11% 12% 5%	2459
	21st to end	Night	12% 60% 4 8% 13% 3	1996
March	1st to 10th	Night	24% 32% 10% 16% 11% 6%	5028
	11th to 20th	Night	15% 31% 10% 16% 15% 14%	5090
	21st to end	Night	25% 29% 8% 19% 15% 3	5588
April	1st to 10th	Night	10% 59% 7% 15% 7% 2	2310
	11th to 20th	Night	8% 61% 7% 9% 11% 5%	2283
	21st to end	Night	9% 61% 7% 12% 11% 1	2163
May	1st to 10th	Night	23% 26% 19% 23% 7% 2	5370
	11th to 20th	Night	23% 25% 16% 27% 9% 1	5235
	21st to end	Night	25% 25% 18% 21% 10%	5771
June	1st to 10th	Night	18% 60% 11% 10% 1	1890
	11th to 20th	Night	19% 63% 12% 6%	1890
	21st to end	Night	14% 61% 17% 8% 1	1890
July	1st to 10th	Night	38% 30% 28% 4	5235
	11th to 20th	Night	41% 27% 25% 6%	5226
	21st to end	Night	38% 26% 24% 12%	5606
August	1st to 10th	Night	38% 31% 21% 5% 4	4257
	11th to 20th	Night	16% 29% 27% 24% 3	4612
	21st to end	Night	33% 35% 27% 6%	5559
September	1st to 10th	Night	19% 62% 12% 7%	2310
	11th to 20th	Night	18% 59% 12% 9% 2	2310
	21st to end	Night	18% 59% 10% 10% 3	2289
October	1st to 10th	Night	42% 38% 12% 6% 3	3590
	11th to 20th	Night	18% 38% 6% 19% 18% 1	3818
	21st to end	Night	20% 37% 5% 20% 15% 3	4252
November	1st to 10th	Night	14% 55% 7% 13% 9% 3	2461
	11th to 20th	Night	16% 55% 5% 10% 10% 4	2520
	21st to end	Night	14% 55% 5% 11% 10% 4	2627
December	1st to 10th	Night	11% 35% 12% 23% 9% 11%	4380
	11th to 20th	Night	22% 31% 9% 14% 17% 7%	4954
	21st to end	Night	35% 29% 14% 12% 8% 1	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	8% 8% 32% 37% 14% 2	330
	11th to 20th	Day	10% 11% 31% 28% 16% 4	330
	21st to end	Day	13% 9% 38% 32% 8% 1	363
February	1st to 10th	Day	8% 7% 25% 38% 17% 5%	330
	11th to 20th	Day	4 5% 31% 38% 19% 4	330
	21st to end	Day	6% 5% 25% 39% 21% 4	352
March	1st to 10th	Day	4 4 32% 38% 19% 2	540
	11th to 20th	Day	6% 7% 27% 34% 24% 2	540
	21st to end	Day	5% 4 24% 39% 24% 4	594
April	1st to 10th	Day	5% 5% 25% 41% 21% 3	540
	11th to 20th	Day	7% 4 20% 39% 25% 5%	532
	21st to end	Day	5% 3 18% 35% 36% 4	540
May	1st to 10th	Day	3 1 17% 36% 33% 10%	543
	11th to 20th	Day	8% 2 16% 30% 28% 15%	567
	21st to end	Day	7% 2 7% 22% 39% 22%	617
June	1st to 10th	Day	13% 2 9% 21% 33% 22%	570
	11th to 20th	Day	6% 2 6% 19% 32% 34%	570
	21st to end	Day	5% 2 2 13% 30% 48%	570
July	1st to 10th	Day	6% 1 3 10% 27% 53%	565
	11th to 20th	Day	5% 1 4 10% 30% 50%	564
	21st to end	Day	8% 1 5% 14% 27% 45%	620
August	1st to 10th	Day	6% 1 3 11% 31% 47%	566
	11th to 20th	Day	5% 1 1 9% 33% 49%	559
	21st to end	Day	9% 1 5% 16% 31% 38%	627
September	1st to 10th	Day	6% 2 4 11% 36% 41%	570
	11th to 20th	Day	8% 2 4 18% 36% 33%	570
	21st to end	Day	5% 2 5% 19% 40% 29%	562
October	1st to 10th	Day	11% 3 9% 28% 39% 10%	530
	11th to 20th	Day	5% 3 11% 30% 38% 12%	530
	21st to end	Day	8% 3 15% 32% 32% 9%	583
November	1st to 10th	Day	7% 4 16% 31% 34% 8%	535
	11th to 20th	Day	10% 4 16% 36% 28% 6%	540
	21st to end	Day	7% 4 22% 33% 26% 7%	429
December	1st to 10th	Day	5% 6% 30% 34% 18% 7%	330
	11th to 20th	Day	8% 6% 24% 36% 20% 6%	330
	21st to end	Day	6% 4 25% 33% 25% 6%	363
January	1st to 10th	Night	8% 5% 23% 43% 19% 2	840
	11th to 20th	Night	11% 5% 25% 41% 17% 1	840
	21st to end	Night	13% 5% 29% 40% 13%	924
February	1st to 10th	Night	11% 4 27% 38% 19%	840
	11th to 20th	Night	9% 4 22% 45% 19% 1	823
	21st to end	Night	9% 4 20% 45% 23%	692
March	1st to 10th	Night	4 6% 25% 46% 17% 1	840
	11th to 20th	Night	7% 5% 22% 45% 21% 1	840
	21st to end	Night	6% 3 22% 46% 21% 1	924
April	1st to 10th	Night	5% 4 21% 46% 23% 1	840
	11th to 20th	Night	5% 4 22% 46% 22% 1	831
	21st to end	Night	6% 2 19% 48% 24% 1	840
May	1st to 10th	Night	4 2 8% 47% 36% 3	671
	11th to 20th	Night	7% 2 8% 44% 34% 5%	621
	21st to end	Night	7% 3 4 32% 46% 8%	683
June	1st to 10th	Night	11% 2 5% 25% 41% 16%	630
	11th to 20th	Night	4 2 4 12% 53% 24%	630
	21st to end	Night	7% 1 2 10% 44% 37%	630
July	1st to 10th	Night	8% 1 2 4 42% 43%	615
	11th to 20th	Night	4 1 1 8% 40% 44%	612
	21st to end	Night	5% 1 8% 43% 42%	690
August	1st to 10th	Night	6% 1 2 7% 47% 37%	627
	11th to 20th	Night	6% 1 1 7% 38% 47%	633
	21st to end	Night	10% 2 4 14% 42% 28%	924
September	1st to 10th	Night	8% 2 3 14% 47% 26%	840
	11th to 20th	Night	10% 2 5% 19% 43% 22%	840
	21st to end	Night	10% 2 6% 23% 42% 17%	833
October	1st to 10th	Night	11% 2 9% 38% 34% 7%	800
	11th to 20th	Night	9% 3 13% 32% 39% 5%	800
	21st to end	Night	11% 2 17% 38% 28% 4	880
November	1st to 10th	Night	8% 2 21% 43% 23% 3	820
	11th to 20th	Night	9% 3 17% 43% 26% 2	840
	21st to end	Night	8% 3 20% 42% 25% 1	840
December	1st to 10th	Night	6% 3 21% 39% 29% 2	840
	11th to 20th	Night	10% 4 20% 41% 23% 3	840
	21st to end	Night	9% 3 22% 40% 24% 2	924

Page generated at 2026-09-26 04:18:41. Version ac07

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