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what temp. is a *light frost*?

Posted by lefleur1 chgo.z5 (My Page) on
Mon, Mar 26, 12 at 20:21

I know 32 degrees is freezing...but at what temp. do we experience a *light* frost? The forecast is for 37 degrees tonight.....

Follow-Up Postings:

RE: what temp. is a *light frost*?

Well, the frost itself only forms when the temp in the water droplets falls to 32 or below. But, a "light frost" can form with an average air temperature somewhere between 33 and about 37/38. Some surfaces radiate heat better than others, which is why you will get frost at times on elevated surfaces such as car windshields, blades of grass, roofs, or mulch when nothing else is frosty.

RE: what temp. is a *light frost*?

Bet you're freaking cuz of this cold front coming in. I'm in a much warmer zone (7b) and I'm concerned, too!! I have weather alerts that text me on my phone and got one tonight, warning about same sort of conditions...and I live in VA, on the east coast by Chesapeake Bay!!!

I AM bringing in all the new plants I JUST bought at KMart today...some annuals, some perennials. Too tender since they just came out of a greenhouse, I'm sure. Also my houseplants I just introduced to outdoors...just to be safe.

There's an earlier post about FREEZING tonight (or something to that effect) from people in your zone. Check it out if that's what your concern is.


RE: what temp. is a *light frost*?

A "light" frost is generally when temps remain above 28 degrees and last only a few hours. A hard or "killing" frost is when it gets below 29 or sub-freezing temps are prolonged (more than 24 hours). Plants are much better able to survive a light frost. Once you get below 28 degrees and beyond 6 hours below freezing, plants are much more susceptible to damage.

RE: above freezing frost

This link explains some of the confusion about why there can seemingly be frost at air temps above 32 degrees.

If you are only scheduled to have surface temps of 37, I would say it is unlikely that you see frost, especially if there is any sort of wind going on.

Here is a link that might be useful: Frost

RE: what temp. is a *light frost*?


if garden could so simply be reduced to scientific certainties ....

IMHO .. there are too many variables to come to any answer with specificity ...

temp is not the only variable ... you must add .. cloud cover .. wind.. micro climate .. and elevation ... and suburbia ...

e.g. .. across my 500 foot wide lot.. which is 8 feet lower in the center 100 feet.. cold air pools as it move from high to low.. since warm air rises.. and many springs.. the forsythia/yoshino cherry ... down there do not bloom in bad years ... due to frost or freezes

so if the forecast is bad.. you have to either go zen.. ala doris day .... what will be will be ...

or you take action.. if you wish ....

but your decision can NOT be made on some precise forecasted temp ... NEVER FORGET ... mother nature is a cruel mistress ... and it brings her supreme delight to mess with our heads ...


Here is a link that might be useful: link

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